Open Panzer

Developer's Forum => Scout Dev => Topic started by: Ncartmell on September 19, 2017, 03:17:22 PM

Title: Home Build
Post by: Ncartmell on September 19, 2017, 03:17:22 PM
I have just received some PCB's for the Scout and OP Sound from china (SEEED). Very good boards, 10 boards @ $4.90 plus $10 shipping, so total cost of $20. That is effectivelly $1 each and the boards have also been electrically tested.

You can also order a solder stencil but I wanted to see the quality of the boards.

The question, can I vary from the BOM.

For instance will non surge 1/10W resistors be ok?

The flash memory is W25Q128FVSG acceptable?

What parts can't be changed?

It also may be of interest that SEEED will manufacture fully populated boards.

I tried to get a price but was unsure if it was complete as there was a warning that all parts were not recognised.

It may be worth pursuing for a production run.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on September 19, 2017, 04:46:24 PM
Yes, you can substitute many components with comparable parts, especially the passives such as resistors and capacitors. Obviously some substitutions are not good, as Hobby King discovered, if you have questions about specific components just ask.

W25Q128FVSG should work just fine, but note the sound card doesn't presently implement the flash memory at all. You can choose to leave it off along with R8 and C3. The flash memory was an idea I was playing with but so far it doesn't seem we will need it.

The important parts on the Scout are the thermistor, diodes, MOSFETs, motor driver, microcontroller and crystal, and the LDO (voltage regulator). Even among those, if you were careful and knew what you were doing you could substitute the thermistor, diodes  and LDO but just use the parts specified to be safe if you can.

The important parts on the Sound card would be the LDO, the micro-SD socket (get the wrong one and the footprint won't line up), and obviously the amplifier IC as well as the Teensy.

I agree SEEED is a great supplier. As for manufacturing, lots of places will manufacture boards but they all seem to want to be paid for it. :) Production runs are extremely expensive and I am not rich. I also don't believe there is any substantial profit to be made from selling RC tank electronics given the size of the market so I don't feel it makes economic sense for me to invest in this financially beyond what the development costs have been (which were considerable). So for manufacturing that really only leaves us with entities willing to shoulder the financial burden themselves... which is a small list indeed.
Title: Re: Home Build
Post by: LukeZ on September 19, 2017, 04:47:21 PM
Also as you build your boards please post over in the Assembling Boards by Hand (http://openpanzer.org/forum/index.php?topic=66.0) thread to ask questions or share your experience.
Title: Re: Home Build
Post by: johnnyvd on October 05, 2017, 06:37:52 AM
I have just received some PCB's for the Scout and OP Sound from china (SEEED). Very good boards, 10 boards @ $4.90 plus $10 shipping, so total cost of $20. That is effectivelly $1 each and the boards have also been electrically tested.

Hi Neil, i'm very curious on how the boards look from Seeed. i have some experience with them because i ordered my flow controller boards with them. I solved this by changing some layer names..

I also tried to order the TCB from them, but as i had to convert Eagle to Gerber files i started losing the bottom silkscreen.

When i look at the price of the boards i guess you did not order with ENIG coating on the pads? OSHpark does that when you order the TCB with them.. Would it matter if we used the standard HASL coating instead?

Could you share some pictures with us? And could you share the Gerber files so ordering them would become easier?

I attached my version of the TCB in Gerber format. I have to remark that the file was never ordered OR reviewed & tested!

(Maybe someone could take a look at it?)

Cheers, John
Title: Re: Home Build
Post by: LukeZ on October 05, 2017, 12:54:01 PM
I haven't gone through the SEEED process so I haven't verified this information. But in the case of OSH Park, they provide an Eagle CAM file for creating the Gerbers. I see that SEEED does as well at the bottom of this page (http://support.seeedstudio.com/knowledgebase/articles/422482-fusion-pcb-order-submission-guidelines).

They give their Gerber files different names than OSH does, and arrange the files somewhat differently. I've gone through each layer and most of the default SEEED selections are fine, except for the silkscreens (as John discovered). But you can always adjust the layers yourself before generating the Gerbers.

In Eagle board view, go to File -> CAM Processor, then File -> Open -> Job and select the SEEED CAM file. Now you will see a bunch of tabs on the CAM Processor form that represent each Gerber to be exported. On each tab you are able to modify which layer belongs to that Gerber file.

For the Silk top we need to add layer 121 _tsilk

For the Silk bottom we need to add layer 122 _bsilk

All the other layers should be fine as-is.

For simplicity, I have attached SEEED Gerbers for all three Open Panzer projects to this post (the Scout is an odd case that removes layer 25 tNames from the top silkscreen because there isn't room for them, but we still need 121 _tsilk).

Again - I've not ordered these from SEEED so I can't promise the results. But they should be correct.

EDIT: I've removed the attachments from this post and put the SEEED Gerbers on the Downloads page (http://www.openpanzer.org/downloads/) instead. This way they are all in one place and I can keep them up-to-date. For those that can I still recommend buying boards from OSH Park, that will be easiest (OSH Park links are also on the Downloads page).
Title: Re: Home Build
Post by: Ncartmell on October 26, 2017, 06:20:08 AM
Hello John,

Sorry for the delay but I have not logged on for a while.

As far as uploading to SEEED I just got the zip files from OSH and then uploaded them to SEEED.

The boards seem ok and I just used all the default settings as this was the first time I have ever ordered boards.


I showed them to someone at work and they were impressed with them.

He says they have been electrically tested as well as he can see the small indentations from the probes.

Apparently they have to pay extra for testing when they buy their boards from another supplier.


I did notice the silkscreen was slightly out.

The only issue I had was getting the stencils made.

If you try and get SEEED to do the stencils then the postage goes through the roof, I think it is a fault with their system.

So I got the stencils made by OSH.

There is an issue with sourcing the parts, the H Bridge is now obsolete VNH2SP30.

There is a replacement VNH3SP30 however it does not have the CS pin, is this an issue Luke?

Ali-express still has the original chip available but only from limited sources.

I will take photos of the boards and upload them.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on October 26, 2017, 10:03:11 AM
There is an issue with sourcing the parts, the H Bridge is now obsolete VNH2SP30.

There is a replacement VNH3SP30 however it does not have the CS pin, is this an issue Luke?

Ali-express still has the original chip available but only from limited sources.

The VNH3SP30 is a pin-compatible part but in function is inferior to the VNH2SP30. If you already have the PCBs and are unable to find the 2SP30 anywhere then you can use it, but the PWM frequency will need to be lowered to 10kHz in code (so it won't be completely silent) and the current-sensing function will be disabled.

The functional replacement for the VNH2SP30 is actually the VNH5019 (https://www.digikey.com/product-detail/en/stmicroelectronics/VNH5019ATR-E/497-13073-1-ND/3455763) however the pins are in a slightly different order so minor alterations to the board must be made. I have intended to do this but the last time I checked the original chip was still widely available so I have not got around to it. It does look as though now the supply is dwindling so I will post a new version of the board soon.

In the meantime as Neil says the original chips are still available on AliExpress and eBay.
Title: Re: Home Build
Post by: Ncartmell on October 27, 2017, 01:33:41 AM
Hello,

Pictures of the SEEED boards
Title: Re: Home Build
Post by: Ncartmell on October 27, 2017, 01:36:08 AM
Second picture
Title: Re: Home Build
Post by: LukeZ on November 01, 2017, 11:36:54 AM
The functional replacement for the VNH2SP30 is actually the VNH5019 (https://www.digikey.com/product-detail/en/stmicroelectronics/VNH5019ATR-E/497-13073-1-ND/3455763) however the pins are in a slightly different order so minor alterations to the board must be made... I will post a new version of the board soon.

I've posted Revision 11 of the Scout ESC board to the Downloads page (http://www.openpanzer.org/downloads/), the only difference is the replacement of the VNH2SP30 with the new VNH5019 chips. Some minor re-routing had to be done so Rev 10 and 11 PCBs and stencils are not compatible with each other, but other than the two motor driver chips the bill of materials is exactly the same.

I've left the Rev 10 files up for those who are building it, but for anyone contemplating a new design go with the new version so you don't have a problem sourcing chips.

I have parts on order to build a Rev 11 board myself just to make absolutely sure the design works, but the changes are so minimal I'm not expecting any issues.
Title: Re: Home Build
Post by: LukeZ on November 01, 2017, 07:01:56 PM
Also FYI, I've started posting Gerbers specifically for SEEED PCBs for all designs on the Downloads page (http://www.openpanzer.org/downloads), and I will keep them up-to-date. For those that can I still recommend ordering from OSH Park so you don't have to mess with Gerbers and you will get a known good, and very purple, board. I believe OSH ships overseas as well. But for those that want to go through SEEED, this should help.
Title: Re: Home Build
Post by: Ncartmell on November 02, 2017, 02:37:33 AM
Hello Luke,
I was purchasing parts for the Scout and OP Sound from DigiKey and several were out of stock.

OP Sound D2 is out of stock so I was going to use the blue LED kitted from the Scout but change the current limit resistor to 560R.
Also a few resistors are out of stock
10K swapped for 11k
2k2 swapped for 2k
1k swapped for 1k1
100k swapped for 110k
Also
BZT52C15S-FDICT-ND swapped for BZT52C15S-TPMSCT-ND
Several caps out of stock but used exact value replacements.

Are these changes acceptable I do not know how critical some of the resistor values are?

Is there a reason why they are Automotive Anti Surge 1/4W?

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on November 02, 2017, 12:41:14 PM
Neil, sorry these parts are hard to find. I typically select parts based on the stock quantity a Digikey, the idea being that if DK has 300,000 units in stock it is probably a part that is going to be around for a while. But even so it surprises me how much changes in a short period of time.

You can use the Blue LED from the Scout on the sound card just fine but you will want to change the resistor R2 on the Sound Card. Since the Blue LED on the Scout operates at 3.3v and the Sound Card also operates at 3.3v, you really don't need a resistor, but put in a 1 ohm so there is something to bridge the pads:
1 ohm resistor (https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNCP0603FTD1R00/RNCP0603FTD1R00CT-ND/2240411)

As for the resistors the "automotive anti-surge" is meaningless, any 0603 replacements will work just fine. On the Scout and Sound Card the resistors don't even have to be 1/4 watt. The values in most cases are not exactly critical but they are all standard values so there is no reason to change them:
1k (https://www.digikey.com/product-detail/en/rohm-semiconductor/ESR03EZPF1001/RHM1.00KADCT-ND/1983752)
10k (https://www.digikey.com/product-detail/en/yageo/RC0603FR-0710KL/311-10.0KHRCT-ND/729827)
100k (https://www.digikey.com/product-detail/en/rohm-semiconductor/ESR03EZPF1003/RHM100KADCT-ND/1983754)
2.2k (https://www.digikey.com/product-detail/en/rohm-semiconductor/ESR03EZPJ222/RHM2.2KDCT-ND/1762929)

Your BZT diode replacement is perfectly fine, looks like the exact same part with a slightly different number.

And yes, caps can be replaced with equivalent value parts, they are not critical either.

Also recall that for now there is no need for the W25Q128 flash chip on the Sound Card, you can leave it off along with the 10k resistor R5. It doesn't look like we'll be implementing any functionality based around that chip.
Title: Re: Home Build
Post by: Lotuswins on November 12, 2017, 08:44:16 PM
Hi Luke,

Okay, we are just back from vacation so now I'm ready to start assembly of the board.  I have the hot plate you recommended, and have checked off all the parts from digitech and others.  I found the board layout finally that shows where to put which part (initially I thought I'd have to trace back from the schematic...yikes!).  So my first question is how much of the solder paste do you put on? and how is it normally applied, manually?  I was thinking of using a small screwdriver to put the paste on each tang of the part and set it down on the board though not much would be needed (the pads are awfully close together!). 

Thanks...obviously my first time at this!   Jerry
Title: Re: Home Build
Post by: LukeZ on November 12, 2017, 09:13:55 PM
Jerry, you certainly can apply the paste "manually" but that would be quite the task and thankfully human resourcefulness has given us shortcuts. But if you were to do it by hand, I would apply the paste to the board using a toothpick, and then place the parts down. I wouldn't apply paste to the parts first, that would be too tricky. Pasting a board with a toothpick is fine for small circuits, but for the Scout I think the effort would be excessive.

What you really need to do is buy a stencil from OSH Stencils. I recently added links to these on the Downloads page (http://www.openpanzer.org/downloads), they probably weren't there when you first started your project so I apologize for that (be sure to buy the correct version, there are two revisions of the Scout now listed on the Downloads page, you no doubt have Rev 10).

The stencil will cost about $15. On checkout you can also buy a "jig set" for an extra 5 dollars, which are probably a worthwhile investment. Eventually you end up with a drawer of spare PCBs and those work just as well as the pre-made jigs but when you are first starting you won't have anything so the jigs are necessary.

Included for free with every stencil is a little spreader, which is basically just a credit card piece of plastic. You could also use a real credit card, or a regular spreader from the hardware store.

Here is a video tutorial that basically shows the process. Practice will make perfect, and also different people have different techniques. For example the guy in this video doesn't tape down his stencil while scraping, he just holds it by hand. In my view this is sheer madness, I always tape mine down (you only need to tape it along one edge, then scrape from that edge and away). If you don't like your paste job you can always wipe all the paste off your board and do it again, so you can practice as many times as you want (using rubbing alcohol for cleanup of your board, stencil, spreader, fingers, whatever).

A good spread will leave a thin film of paste on the board no taller than the thickness of the stencil. You really don't need much, less than you'd probably think. You might find it difficult on the ATmega processor to get the pins pasted cleanly so that the paste isn't smeared across multiple pins - don't worry, the paste will separate onto each pin individually during reflow, provided you didn't put too much on. Watching the solder re-flow is a magical experience. But remember not to burn it!

Feel free to ask questions as you go along.


Title: Re: Home Build
Post by: LukeZ on November 12, 2017, 09:30:07 PM
For placing components on the board curved tweezers work best in my experience, I've been using a cheap set I got from Harbor Freight but you can probably find even a nicer curved tweezer in the beauty aisle at Walgreens or the like.
Title: Re: Home Build
Post by: LukeZ on November 12, 2017, 09:35:34 PM
I found the board layout finally that shows where to put which part (initially I thought I'd have to trace back from the schematic...yikes!).

For others reading this later, here is the Scout placement guide Jerry mentioned, from this thread (http://openpanzer.org/forum/index.php?topic=66.0).

Placement is the same for Rev 10 and 11.
Title: Re: Home Build
Post by: Lotuswins on November 12, 2017, 11:15:51 PM
Thank you so much Luke, you are the man!!

So I just ordered the stencil, 3 mils since I thought the thinner, the better.  Plastic, with a frame to ease the pain 8^).    Its getting easier already. 

I'll try out the heat plate tomorrow using my handy dandy Duratrax RC IR temp monitor while waiting for the stencil to arrive.  The paste bottle doesn't say its recommended melting point (the Mechanic Solder Paste from ebay/China I think you recommended), I assume its 200C, right?

Thanks again!!   Jerry
Title: Re: Home Build
Post by: LukeZ on November 12, 2017, 11:32:12 PM
Yes, the 3 mil plastic is what you want. And yes, I try to keep the temperature to 200* C. I think the actual melting point of the paste is something like 183* Celsius but you need to go a little higher than that of course. If you keep it to 200* C you will have a very nice result.

If you go a few degrees over, don't sweat it, it's not the end of the world. But if you hit 210* C you are probably going to see discoloration of the bottom of the board including the silkscreen, and beyond that you risk delaminating the bottom copper and damaging the ICs.

OSH Stencils ship quickly, not like waiting for PCBs to be made. You will probably get the stencil this week.
Title: Re: Home Build
Post by: LukeZ on November 13, 2017, 12:28:59 AM
Another thing you can prepare for while you are waiting, if you haven't already, is the equipment you will need to program the microcontroller on the Scout. I haven't really posted about this because I assume people going through the trouble of assembling an SMD board at home probably already know this stuff, but for everyone's benefit here is a quick primer:

The ATmega chip on the Scout needs firmware, which you can flash to the chip using OP Config (or the Arduino IDE) and a standard FTDI cable (basically a USB-to-serial converter). BUT, before you do that, the chip will need a bootloader installed. Without the bootloader the chip can't even communicate yet over serial so to get the bootloader on requires a special one-time programming using a different device called a "programmer" connected to the ISP port on the Scout (ISP stands for "in-system programmer").

There are lots of compatible programmers but the cheapest that works well is the USBasp (actually Chinese knockoffs of it). These only cost a few bucks. I have used this one (https://www.aliexpress.com/store/product/1PCS-USBasp-H6-USB-ISP-5V-AVR-Programmer-USB-ATMEGA8-ATMEGA128-New-1PCS-6PIN-Wire-Support/223246_2036401781.html?spm=2114.12010612.0.0.37a0fb60V9q69u) but they are sold all over the place including AliExpress, Banggood, eBay, etc... Note that many of them come with a 10 pin plug and you actually need a 6-pin, so be sure to get one with an adapter (such as the one linked) or buy an adapter separately (like this (https://www.aliexpress.com/store/product/1PCS-10Pin-to-6Pin-Adapter-Board-for-AVRISP-MKII-USBASP-STK500-High-Quality-BTE13-006/223246_2036402715.html?spm=2114.12010612.0.0.37a0fb60E9EaqX)).

You will probably need drivers for the USBasp device, try these (http://zadig.akeo.ie/).

Ok, now you have your USBasp and your assembled Scout. The USBasp plugs into a standard USB port on your computer. The ribbon cable on the other end you need to connect to the ISP connector on the Scout which is the 6-pin rectangular connector in the corner of the board (shown in the image below). Align the red stripe on the ribbon cable with the little white triangle on the Scout board. You can either solder headers in those holes and just plug in the USBasp connector, or you can leave the board bare (as shown in the photo) and use a pogo-adapter like this one sold by SparkFun (https://www.sparkfun.com/products/11591) (just hold it on the holes in the board and press down tight). Note that you also need to power your Scout with a battery while performing this operation. Now you are connected, open up the Arduino IDE (you don't need to load any kind of sketch). Under the Tools menu:
- Select "Arduino Nano" as the Board
- Select "ATmega328" as the Processor
- Select "USBasp" as the Programmer
- And finally click on "Burn Bootloader"

If all goes well the bootloader will be installed (Arduino will tell you whether it was successful or not). If it works, you can put away your USBasp, you will never need it again.

Now you need to load firmware. This is much easier. You need an FTDI adapter (like this one (https://www.adafruit.com/product/284) or this one (https://www.sparkfun.com/products/9716)) or just an FTDI cable (like this one (https://www.adafruit.com/product/70) or this one (https://www.sparkfun.com/products/9718)), or any others that are legit "FTDI" cables/adapters (buy these from a reputable source or you will have driver issues). I prefer the adapters but you will need to supply your own USB cable then. The FTDI adapters/cables use the same drivers as the TCB so you probably already have them on your computer but if not you can get them from the Downloads page (http://www.openpanzer.org/downloads).

Once you have the FTDI drivers installed the rest is easy. One end plugs into your computer using standard USB, the other 6-pin wide plug connects to the Scout on the header shown in the image below. Note that one side of the FTDI connector will be labelled "Green" and the other end "Black", make sure these are aligned with the words "Green" and "Black" printed on the Scout board. For this operation it is not necessary to power your Scout with a battery, it will get power from the FTDI cable (though it doesn't hurt if a battery is connected). One thing you do need to make sure of is that you disconnect your Scout from the TCB if you had it plugged in there, because that will cause the firmware update to fail. Now just open up OP Config, select the correct COM port for your FTDI cable, go to the Firmware tab, select Scout ESC and "Get Latest Release", once that is downloaded click the Flash button and your Scout will be programmed. If you are really a glutton for punishment you could download the Scout source code from GitHub, open the sketch in Arduino, then program it from there.

Note that all this rigmarole is the same for the TCB if you are building one of those by hand, except there is no point in doing that since we can now purchase them. For the Open Panzer Sound Card none of this is necessary - the Teensy processor used on the Sound Card already comes with a bootloader pre-installed, and furthermore it requires no special Windows drivers. To load/update firmware for the Sound Card just plug it into your computer with a USB cable, then use OP Config to flash the latest firmware, should take five seconds.
Title: Re: Home Build
Post by: pandknz on September 01, 2018, 11:54:49 PM
Hi all

I have just placed an order with Digi-Key for the components, with a bit of their help I have added some alternative parts and these are all available.
If you see something wrong please let me know

Cheers
Title: Re: Home Build
Post by: LukeZ on September 02, 2018, 01:54:33 PM
The BOM looks fine to me.
Title: Re: Home Build
Post by: LukeZ on December 17, 2018, 01:56:35 PM
Quote from: Ncartmell
Hello Luke,

I am finally going to test the TCB, Scout and OP Sound together.

Just a quick question on the serial link wiring.

Looking at the schematics I was going to wire basically pin to pin, as follows:-

TCB Pin 2 (Tx) to Scout/OP Sound Pin 2 (Rx)

TCB Pin 3 (Rx) to Scout/OP Sound Pin 3 (Tx)

I assume Pin 1 (GND) is not required if all powered from the same battery.

Is there any chance of continued firmware support for R10 of the Scout?

Best Regards

Neil

That's correct, except because the sound card has two connectors, the typical approach would be to connect the TCB to one of the connectors on the sound card, then use the second connector on the sound card to go to the Scout. In this case the connection to the sound card is just as you've described:
TCB TX -> Sound Card RX-I
TCB RX -> Sound Card TX-O

Then from the Sound Card to Scout:
Sound Card RX-I -> Scout RX-I
Sound Card TX-O -> Scout TX-O

That second connection is slightly confusing due to the nomenclature on the board, but just treat the Sound Card as a straight pass-through of the TCB signal.

You are also correct that if all three boards share a common ground, then the GND pin of the serial connector is not required, but it would not be a bad idea to include it anyway.

As for R10 of the Scout - I am not planning to continue firmware development for it, however as of right now it possesses all the same features as R11 firmware. In other words, R11 does nothing that R10 doesn't, it just uses different chips.
Title: Re: Home Build
Post by: Ncartmell on December 18, 2018, 02:34:34 PM
Hello Luke,

Mixed results on testing the Scout, I will test Op Sound later.

All firmware appeared to load correctly.

After playing with TCB for a while I got forward movement and left forward turns on M1.

Scout has solid Blue LED so serial connection appears Ok.

No other motor control was available (M2 nothing, no reverse and No right turns).

Could you email a .opz file for just basic control with no triggers/events so that I can eliminate my inexperience with setup.

I am also suspecting my Radio, Graupner MX12 with a Corona RP6D1 (I modified for serial PPM O/P). However Red/Green LED's seem to show correct motor control on the TCB.

Neil
Title: Re: Home Build
Post by: LukeZ on December 19, 2018, 12:40:56 AM
Almost certainly the issue is a short on the motor driver chip M2 during reflow. This is not hard to do, and I have done it myself on occasion.

The fact you are getting correct lights, and correct functioning of M1, tells me the firmware and your radio setup is working as it should. There is nothing different from the software's point of view, of controlling motor 1 versus motor 2. If you had an issue with your radio or your receiver, you would also not be able to get motor 1 working at all. The fact that so much works, but one thing does not, tells me the problem is almost certainly a physical issue with your Scout.

Because the motor driver chips have large pads on their underside, it is very easy for them to short if you put too much solder paste on them before reflow. You can check the visible pins of the M2 chip for shorts, and if you see a short you can try to correct it with a soldering iron. But more than likely the short is on the underside where you can not see it and can not fix it. You really almost can't have too little solder paste when assembling these. The thinnest layer possible is what you want, anything more can cause problems.

There's no need to send you a "basic" opz. You can reset all values to default yourself within OP Config (look in the Tools menu). And you can easily delete the four standard triggers that come with the default settings (select each one on the Functions tab then click "Remove Selected Row"). But really the most important thing is that you have radio setup completed correctly, but it sounds like you do.

I'm afraid you're looking at building another Scout. Unfortunately without special equipment you are not likely to get the motor chip off and replaced, without destroying the rest of the board.
Title: Re: Home Build
Post by: Ncartmell on December 19, 2018, 12:30:01 PM
Hello Luke,

I looked at the board today with a magnifier and I could see a tiny amount of solder that has squeezed from under M2, so I think your assessment is spot on.

I am glad this has happened with my first build as I will now  use the mask for applying solder paste to the board but not for under the IC's.

I will attempt to remove the IC's.

At work I have access to a desoldering station to remove the connectors, I will then take advice if the Hot Air Station will be able to remove the IC's.

If this is not possible I will try the hot plate and try to lift off the IC's when the solder melts, nothing to lose as the board is non functional.

Many thanks.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on December 19, 2018, 01:25:18 PM
The hot air rework station is probably your best bet, since it should be able to remove the chip without melting too many other components around it. Good luck, and keep us posted.
Title: Re: Home Build
Post by: Ncartmell on December 30, 2018, 12:15:26 PM
Hello Luke,

I have completed the build of two more Scout's and I just used a very small amount of paste on the pads under the IC's.

I examined them under a magnifier and I checked for "shorts" prior to powering them up, everything looked good.

Bootloader and firmware loaded ok.

Both however did not work perfectly, both motors ran but not correctly and I am puzzled.

If I number the positions on the throttle/steering joystick as follows to make explanation easier and then say which motor ran.

1 Full Forward left
2 Full Forward
3 Full Forward right
4 Left Neutral
5 Centre
6 Right Neutral
7 Full Reverse left
8 Full Reverse
9 Full Reverse right

Scout 1 (Impedance min 200k, Motor O/P's wrt to Bat +ve)
1 M1
2 M1 & M2
3 M2
4 M1
5 None
6 M2
7 M1
8 M2
9 M2

Scout 2 (Impedance min 200k)
1 M1
2 M1
3 None
4 M1
5 None
6 None
7 None
8 M2
9 M2

Scout 3 (first build, I have done continuity check and lowest impedance was 200k)
1 M1
2 M1
3 None
4 M1
5 None
6 None
7 M1
8 None
9 None

Since both motors ran for TCB's 1 & 2, the Motor IC's should be ok, could there be a component failure, wrong value, dry joint or ?
Any suggestions?

Can you monitor the serial stream to see if the correct information is being sent by the TCB.

Currently I do not have a gnd connected for the serial lead but I have a Blue led.

Regards

Neil
Title: Re: Home Build
Post by: LukeZ on December 30, 2018, 02:14:44 PM
The Scout can be connected to OP Config in Snoop mode, but I can't remember how much information it gives out. I think at this point however we are safe in assuming the firmware is operating correctly, and we need to look elsewhere for the problem.

The first thing I would do is connect the ground on the serial connection. Your results appear to be somewhat random and this could indicate a poor communication link.

Secondly, what version of the Scout board have you built and which ICs are you using? Hopefully not, but it could be possible you have put the wrong IC on the wrong board.

Also, note that it is possible to short a motor IC such that it will work in one direction but not the other. Excessive heat on the motor IC is also a good signal that something is wrong. This may be the case on your Scout 2.

Third, you can eliminate the TCB and serial communication entirely by running the Scout in RC mode. A servo tester is convenient for this purpose but you can also just hook it up to a standard RC receiver. This is a simple and straightforward way of testing the hardware. If the motors don't move in forward and reverse with a basic RC signal, the likelihood is that you have a short or some other physical problem.

Your Scout 1 seems to have the most functionality. I almost wonder if maybe you have an issue with Radio Setup, possibly inadvertent trims set on your transmitter, or the like. Run it in plain RC first to verify the motors are working, and if so, re-do radio setup and try it again with the TCB (with ground connected on the serial port).

Title: Re: Home Build
Post by: Ncartmell on January 26, 2019, 08:13:08 AM
Hello Luke,

I couldn't find my servo tester so I have ordered another, put it away safely 😂.

Whilst browsing for some more VNH2SP30 motor IC's I noticed you can buy them pre made for use as single motor boards or as a twin Arduino shield.

So I bought two singles, the shield, a micro Nano and an R3 UNO.

On Intstructables website they have a tutorial on the Nano and Shield setup with code.

So I thought if I modified your code to run on this it would be an "alternative" Scout.

Although no temp monitoring/ fan control, I will add volt sense.

However on Github I cannot see the code for the R10 scout, could you let me have a copy?

Also I will modify the "Instructables" code to run on the Scout, as you can then control it using the USB from your computer.

I have never used these "Arduino" things before also the last time I wrote code was in the late 70's and it was Fortran77, so this will be a good learning exercise.

If it all works ok I will post the build with results.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on January 26, 2019, 11:33:21 AM
Hi Neil, I also used those cheap VNH2SP30 carrier boards when I was first testing. At some point the money you spend will equal what it would have cost you to just buy the Pololu Qik 2s12v10 (http://) which is very similar to the Scout! But then you wouldn't have the fun of coding and frying things.

The last version of the Rev 10 firmware can be found on this page (http://openpanzer.org/forum/index.php?page=old_scout) (it's just a hex, use OP Config to flash it to your Arduino). You can also see the Rev 10 schematic on that page, which you will want to follow.

But, you can actually still use the code on GitHub, which will let you see how it all works. You just need to change the line at the top of the OpenPanzerScout.ino file, around line 30:

Code: [Select]
    // Motor Chip Selection
        const uint8_t MotorChipVersion =    2;          // 1 - VNH2SP30, used on Scout boards through Rev 10
                                                        // 2 - VNH5019,  used on Scout boards from    Rev 11

Set MotorChipVersion = 1 to revert to the VNH2SP30 version. In fact the only real difference is in the way it reads current draw since the two versions of the chips report it slightly differently.

Have fun testing and keep us posted on your results!
Title: Re: Home Build
Post by: johnnyvd on February 06, 2019, 01:20:23 AM
Wow, i just found a good source for the Polulu in Europe: https://www.tme.eu/nl/details/pololu-1112/modulaire-motorcontrollers/pololu/qik-2s12v10-dual-serial-motor-controller/# (https://www.tme.eu/nl/details/pololu-1112/modulaire-motorcontrollers/pololu/qik-2s12v10-dual-serial-motor-controller/#) only 66 euro's if you buy three or more..
This even comes close to building my own scouts..
Title: Re: Home Build
Post by: Ncartmell on February 20, 2019, 04:12:23 PM
Hello Luke,

Making slow progress, I have managed to modify the Instructables code to drive a Scout using USB.

Only basic Forward, Reverse, Left, Right, Speed Up/Down and LED's On/Off.

Enough so you can test the functionality without TCB and/or Servo Tester.

Hopefully I will then be able to get my Scout's working.

I have a rough idea what is wrong with each of them.

I have made a small Vero board interface adaptor with LED's so the TCB can work with the UNO/Motor Shield.

Now to modify your code.

On Github you have a main file and then some individual smaller files.

The main file seems incomplete without the others.

So do I need all the files?

If so how are they linked?

Sorry for the dumb questions, software was my weak point and the last time I did any coding was 1987.

The total cost for the UNO, Motor Shield and Vero board will be $10

It is interesting playing with these bits.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on February 20, 2019, 06:43:09 PM
Browsing back through the last few posts, it seems as if you are trying to create your own Scout from off-the-shelf parts with a UNO as processor and some code you found on Instructables. It sounds as if you have gotten the Instructables code to work, and now you have whatever functionality it gives (apparently control from your computer), but obviously it does not have the functionality that would be found in the Scout code. Therefore it will not interface with the TCB. 

From your comments and questions I do think there is a large amount of basic programming knowledge that you would need to acquire first before it would be worth discussing specific firmware issues.

Does your Instructables project allow control via standard RC signals? If so, you might be able to use it with the TCB without any firmware changes since the TCB is also able to drive standard RC speed controllers, and you would have essentially built yourself a standard RC speed controller.

Title: Re: Home Build
Post by: Ncartmell on February 21, 2019, 06:43:10 AM
Hello Luke,

My plan was to only use the Modified Instructables code to test the UNO/Shield I have bought and also test the Scouts I made.

I also bought a Servo tester which proved the Scouts were faulty and not the Radio/TCB setup.

The Scouts perfom as expected with the Modified Instructables code.

My aim was to modify your code to work on the COTS UNO/Shield setup.

All I need to do is remove the Fan/Address/Thermistor sections from your code and re-allocate the pin assigments.

The pin assignment is done.

The code in GITHUB appears to have been split into different files and I assume needs putting back together into one file.

OpenPanzerScout.ino
FAN.ino
INPUT_RC.ino
INPUT_SERIAL.ino
SENSORS.ino
MOTOR.ino

If it works I will put the code in GITHUB (with your permission) so that other people who wish to use a SCOUT but cannot build one can go down the COTS route.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on February 21, 2019, 02:09:36 PM
Ok, it is more clear now. Yes I will be interested to hear if you can adapt the code for COTS use. If you do get it working, feel free to post it to GitHub, I will be interested to take a look at it. It may be possible to integrate the two versions into one with a flag being set to select which hardware it runs on (similar to the Rev 10 / Rev 11 flag).

Yes, the Arduino project is split into multiple files and no, they do not need to be combined.

The best way to edit the source is to clone the project from GitHub to your own computer, but if you are having challenges with Arduino 101 then I suspect it may not be worth learning the intricacies of GitHub of which even I am but a novice.

Alternatively just download the project (you can click the download button on the GitHub page, or go to the Open Panzer Downloads page (http://openpanzer.org/downloads#scout) and under the Scout Firmware section click "Download Zip"

Unzip the folder on your computer. At the root you will see two folders and some text files, for your purposes you only need the folder called "OpenPanzerScout." Copy that folder to your Arduino sketches directory (if you are unclear of where this is at, open Arduino, click the File menu, then Preferences, then look for the entry called "Sketchbook location").

After you copy that folder to your Sketches directory, double-click on any of the ".ino" files inside it and Arduino should open the project. Yes there are 7 distinct files, and Arduino will open all 7 and array them as tabs in your editor. Arduino knows to treat them as one project, but having multiple tabs is handy for organizing the code into various sections.
Title: Re: Home Build
Post by: Ncartmell on April 30, 2019, 06:49:27 AM
Hello Luke,

It has been a while but I have slowly gone through the code and I have modified to suit the COTS installation.

Pin assignments changed, fresh values for Timer0 registers and code commented out.

It compiles ok and now needs checking.

However as part of doing the changes and with references to the 328 datasheet it appears that the best (highest) PWM frequency that can be achieved from Timer0 that will work with the VNH2SP30 chips is 4KHz.

I will see what happens.

If it does not work I have a plan "B", which involves cutting 4 tracks on the UNO board and adding 4 wires which will effectively re-wire the Timer1 pins to the Timer0 pins.
I have already changed the code to accomodate Plan "B".
This will bring it back into line with the SCOUT PWM output wiring.

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on April 30, 2019, 02:35:06 PM
It's true. The Monster Moto Shield (https://www.sparkfun.com/products/10182) (and Chinese clones) route the two VNH2SP30 PWM lines to pins D5 and D6 on the UNO, which are mapped to the 8-bit Timer 0 on the ATmega328. The Scout hardware uses pins D9 and D10 which are mapped to the 16-bit Timer 1. The 16-bit timer allows us greater flexibility in the selection of PWM frequency. On the Scout the frequency is set to ~21KHz which is ultrasonic.

With the 8-bit Timer 0 you have fewer options but you can do better than 4KHz. I assume you derived 4KHz by using Phase-Correct PWM with a prescaler of 8 and a TOP value of 255 (the max that you can go with an 8-bit timer). However, you can use Fast PWM mode instead, again with a prescaler of 8 and a max TOP of 255 and you will end up with ~7.8KHz. That is still well within the range of human hearing but the motor whine will not be quite so annoying as 4KHz. I'll let you look at the datasheet and figure out the registers, but also make sure to change the MOTOR_PWM_TOP definition to 255.

Note that you will also have to change the function that translates the serial commands to speed commands, this is at the bottom of the INPUT_SERIAL tab. With the 16-bit Timer 1 we use a custom TOP value of 381 which we selected both because it gave us a perfect PWM frequency but also because it is exactly 3*127 and our speed signal comes in as a value from 0-127. So we multiply the incoming value by 3 and use that to set our pulse-width.

If you use an 8-bit timer with a max TOP of 255 you will have to scale the incoming value by 2 instead of 3.

Code: [Select]
int16_t getSpeedCommand_fromSerial(uint8_t val)
{
    // Serial speed commands should be 0 to 127.
    val = constrain(val, 0, 127);

    // MODIFIED VERSION FOR 8-BIT TIMER
    // Multiply by 2 to scale our speed value (from 0 to 127) to our PWM duty cycle range (0 to 255)
    if (val == 127) return 255;
    else            return val * 2;
}

As for RC the code will adjust automatically.

Anyway you are getting a good look under the hood, and it becomes clear why certain design decisions were made. I too looked at the motor shields early on but sadly the way they are wired is not ideal for our purposes.
Title: Re: Home Build
Post by: Ncartmell on May 02, 2019, 07:13:56 AM
Hello Luke,

I did consider the FAST PWM but thought as you used Phase Correct I would stick with that.
Since you now mention using Fast PWM,  am I correct in assuming the Phase Corect was only chosen so that you could more precisely set the PWM frequency?

I noticed the Motor_PWM_Top definition but I have commented this out as you only seemed to use this for setting ICR1 and as this is not used with Timer0 and the value of TOP is predefined as 255.
Am I correct with this?

The multiplcation of the speed I did change to 2 but I am confused with the code you have shown.
I had changed the code as below

{
    // Serial speed commands should be 0 to 127.
    val = constrain(val, 0, 127);

    // Now multiply by 2 to scale our speed value (from 0 to 127) to our PWM duty cycle range (0 to 255)
    return val * 2;       
}


You have an extra line which is not in the code from Github and checks for the max value
if (val == 127) return 255;

Is it necessary?

It takes a while for me to understand code but I normally get there, however writing from scratch is a complete no no.

Going through all the routines is interesting as I am learning quite a bit.

Cheers

Best Regards

Neil
Title: Re: Home Build
Post by: LukeZ on May 02, 2019, 05:11:21 PM
Since you now mention using Fast PWM,  am I correct in assuming the Phase Corect was only chosen so that you could more precisely set the PWM frequency?
Yes that's correct. Either type of PWM will work fine for driving the motor but we can have different frequency options with each one. My goal was to get to 20Khz or above because the whiney-motor phenomenon really bothers me.


I noticed the Motor_PWM_Top definition but I have commented this out as you only seemed to use this for setting ICR1 and as this is not used with Timer0 and the value of TOP is predefined as 255.
Am I correct with this?
Actually MOTOR_PWM_TOP is also used in the function "getSpeedCommand_fromRC" on the INPUT_RC tab and your sketch shouldn't even compile if you commented out the definition, but maybe you have re-moved all the RC code I don't know. If you intend to leave the RC stuff in then you need to leave that defined (and set it to 255) because that is used to auto-scale the signal from the RC radio to an accurate PWM speed command.


The multiplcation of the speed I did change to 2 but I am confused with the code you have shown.
I had changed the code as below ...

You have an extra line which is not in the code from Github and checks for the max value
if (val == 127) return 255;

Is it necessary?
Right, I did add a little bit there. You can just multiply it by 2 as you have done, but note that 2*127 = 254 so you will never actually be able to get to full on which is 255. I doubt you'd notice it but that is why I threw in that extra line.

We didn't need to do any tricks like that in the stock code because I picked a custom TOP value that is exactly 3*127 (381). To do the equivalent thing here we'd want to pick a custom TOP value of 254 instead of 255, but when using the 8-bit Timer 0 the options for custom TOP values are not as convenient so just set it to the fixed value of 255 (WGM0 2:0 = 3, this requires setting bits in both TCCR0A and TCCR0B).

Actually, here is what I have for the new 8-bit setup, you can compare with yours and see if we match:
Code: [Select]
// TIMER 0 - MOTOR PWM
// ---------------------------------------------------------------------------------------------------------------------------------------------->   
    // We use Timer 0 to generate ~7.8KHz PWM on Arduino pins 5 & 6 (PD5 and PD6). Ken Shirriff has a good tutorial on the various types of PWM possible: http://www.righto.com/2009/07/secrets-of-arduino-pwm.html

    // We want:
    // - Waveform Generation Mode bits (WGM0 2:0) - split across TCCR0A and TCCR0B. These set the PWM modes, we want Mode 3 - Fast PWM with a fixed TOP value of 0xFF (255). See page 109
    // - Clock Select (CS0 2:0) - last three bits of TCCR0B which set the prescaler, we want prescaler of 8. See page 111.
    // - Compare Match Output A & B bits (COM0A, COM0B): Two bits each, in TCCR0A register, these enable/disable PWM on the associated pins. See page 107.
    //   The pins we are using are Arduino pins 5 & 6 or in other words, Atmega port D pin 5 and 6.
   
    // To control the duty cycle (set the motor speed), we write to OCR0A or OCR0B a value between 0-TOP (0-255)
    //OCR0A = 0-TOP;    // To set duty cycle on Arduino pin 6
    //OCR0B = 0-TOP;    // To set duty cycle on Arduino pin 5
   
    // The frequency is determined by the PWM mode (Fast PWM mode in our case), the clock frequency, the prescaler, and our TOP value.
    // Formula for Fast PWM is (Clock/Prescaler/TOP) = 16,000,000 / 8 / 255 = 7,843 Hz
    // Low frequencies result in "motor whine" which is annoying and doesn't sound realistic on a model. The VNH2SP30/VNH5019 motor drivers used on this device have a maximum PWM frequency input of 20Khz, though this
    // is not absolute. Higher frequencies cause less efficient operation and create more heat. Human hearing typically extends to about 20Khz, so above that the PWM should be inaudbile.
    // When using the 8-bit Timer 0 the best we can do is ~7.8KHz, which will still be audible but not terrible.
    // When controlled via serial the speed is passed as a 7-bit speed number (meaning values from 0-127), so we must multiply them by 2 to scale them to the PWM range of 0-255 for OCR0A and OCR0B.

    TCCR0A = 0xA3;              // COM0 A1:A0, COM0 B1:B0 = 10 (connect non-inverted PWM to pins), WGM0 2:0 = 011 (Mode 3, Fast PWM with TOP = 0xFF)
    TCCR0B = 0x02;              // CS1 2:0 = 010 (Prescaler = 8)
    TIFR0 =  0x07;              // Start off with all Timer 0 flags clear (by setting bits to 1 in TIFR0 register)
    TIMSK0 = 0x00;              // Disable Timer 0 interrupts (by clearing TIMSK0 bits). PWM is generated in hardware and we won't need interrupts enabled for it.
    TCNT0 = 0;                  // Reset TCNT0
    OCR0A = 0;                  // Start off with duty cycle for both motors at 0 for safety.
    OCR0B = 0;                  //


Note we won't be doing anything with ICR1 in this case, because TOP is fixed and anyway our 8-bit Timer 0 doesn't have a corresponding ICR0.


It takes a while for me to understand code but I normally get there, however writing from scratch is a complete no no.

Going through all the routines is interesting as I am learning quite a bit.
Frankly I learned everything I know from looking at what others had done, I don't have a degree or training in programming or electronics. Eventually you see enough you can put the pieces together yourself in new ways, and you also get pretty familiar with component data sheets, but still, the original foundation of everything came from somebody else. That's why open source is so great, none of us have to start from square one. Your project is a perfect example!
Title: Re: Home Build
Post by: johnnyvd on February 11, 2020, 04:07:44 PM
Hey luke, i recently reflowed an older version of the Scout. Everything looks fine, but i'm not able to get bootloader/firmware installed.

I used an Arduino UNO as ISP to Burn the Bootloader to the Scout. ArduinoISP says "Done Burning Bootloader" with no further info.
But when i try to upload the firmware with a FTDI i get a "programmer not responding" error..:

avrdude : stk500_recv(): programmer is not responding
avrdude : stk500_getsync() attempt 1 of 10: not in sync: resp=0x3e


Also, no leds on the Scout are flashing.. I guess this is normal with only the bootloader on it?
Something wrong with my FTDI programmer? Or are there suspects on the board that could cause this?

Cheers, John
Title: Re: Home Build
Post by: LukeZ on February 12, 2020, 04:25:32 AM
If the bootloader process doesn't give an error then we would expect it has worked, though I seem to recall the confirmation being somewhat more verbose than you describe.

The bootloader is flashed using the 2x3 ICSP header so it is a different set of pins than the FTDI used for firmware. Therefore it is possible you could have a shorted pin on the latter that would prevent it from working, even though the ICSP pins are fine. The most probable place to check is on the processor itself, the legs are close together and sometimes there might be a bridge between them, try to look at it with a magnifying glass if you have one.

It's true that prior to loading the sketch the LEDs will not behave in the normal Scout manner, however, the red LED is connected to the same pin as the default LED on stock Arduinos, and this typically will blink even with only the bootloader, at the very least when first powered up, but I seem to recall it blinks at about a rate of once per second. So if the red LED does nothing at all it may be that the bootloader install was not successful.

I would go through the bootloader process again, making sure that you provide battery power to the Scout during the process, and making sure you have selected Arduino Nano as the target board.

It is also possible to load the sketch using the ICSP connection rather than FTDI, in the Arduino IDE go to Sketch -> Upload Using Programmer. This will over-write the bootloader if it is on there, so subsequent firmware loads will have to be done using the programmer unless you put the bootloader back on. But it might be something to try.

I suppose another possibility depending on where you got the ATmega 328P chips is that they could be counterfeits, this has been known to happen...
Title: Re: Home Build
Post by: johnnyvd on February 18, 2020, 01:46:38 PM
Well, i tried to burn the bootloader several times, but my guess was that the Atmel was not genuine (well, i could not trace back the source).
I ordered several from Farnell so i have a trustworthy source. Also ordered some new SMD LED just to be sure that i have the specification of the cathode side.

Desoldered the old Atmel and soldered the new one back (hail the desoldering station!) and even desoldered an soldered the SMD Led's to check polarity..
Turned on verbose in ArduinoISP and burned the bootloader. Got some errors, but then with magnifying glasses it found some pins where not soldered right.

Second time Bootloader burning Logging say's everything went ok.. But no flashing leds? Maybe they burned out from reversed polarity?
Also i still get the same error when i try to flash the Firmware.. Still not responding..

Loading the sketch using the ICSP is not completely clear to me.. What sketch should i upload? Do you have a Firmware Sketch available?

Title: Re: Home Build
Post by: LukeZ on February 19, 2020, 06:59:14 AM
Hi Johnny,

A few other things to check - when loading the firmware over FTDI, the Scout can not be connected via Serial to your TCB, otherwise it will fail. I should have mentioned this earlier. The Scout does need battery power during programming, but be sure to unplug the serial cable to the TCB during the programming operation. It won't damage anything if it is connected, but the programming won't work.

Also be sure to select the correct COM port for your FTDI adapter, and double-check that you are connecting your FTDI adapter in the correct orientation to the board. Out of curiosity what FTDI adapter are you using? These adapters can also be a source of problems, especially the Chinese ones. You may want to confirm the FTDI adapter itself is actually functional. 

Out of curiosity, I wonder also what ICSP programmer you are using to flash the bootloader?

As for loading the sketch using ICSP and the Arduino IDE, you can download the Sketch from GitHub, here is the link (https://github.com/OpenPanzerProject/Scout-ESC).

Click on the green "Clone or Download" button and select "Download ZIP." Unzip the file, there will be a few folders and files in there, you only need the "OpenPanzerScout" folder which you should place in your Arduino Sketch directory, wherever that is (you can find the location in the Arduino IDE by going to the File menu, selecting Preferences, and you will see the path to "Sketchbook Location" near the top of the popup form).

Now open this sketch in the IDE, select "Arduino Nano" for the board and select the correct Port. Now typically from here you would program the sketch on to your device using the right arrow button at the top of the IDE (via your FTDI adapter), but if you want to program the sketch using the programmer go to Sketch menu -> Upload Using Programmer (in this case you also of course need to specify what programmer you are using in the Tools menu, same as for doing the bootloader).

Let me know what happens...
Title: Re: Home Build
Post by: johnnyvd on February 20, 2020, 03:18:33 PM
Hi Luke,

Thanks for your help. I got the Sketch loaded by using a Arduino UNO on ICSP. Red light, blue light. everything works..
Guess my FTDI adapter is a cheap copy.. Any suggestions on a good brand/type to buy?

Only problem i have now is that my M2 channel is not working like in one of the previous posts. It seems i have a short on the lower pads (i guess)..

Almost certainly the issue is a short on the motor driver chip M2 during reflow. This is not hard to do, and I have done it myself on occasion.

If i manage to remove the chip, is it still usable after the short?
Title: Re: Home Build
Post by: LukeZ on February 21, 2020, 03:34:08 AM
Guess my FTDI adapter is a cheap copy.. Any suggestions on a good brand/type to buy?
I usually recommend the Adafruit FTDI Friend (https://www.adafruit.com/product/284) or the SparkFun version (https://www.sparkfun.com/products/9716), but I don't know how easy it would be to obtain them in Europe. It looks like Farnell has an adapter too, here is the UK site (https://uk.farnell.com/ftdi/ttl-232r-5v/usb-to-serial-converter-cable/dp/2419945).


Only problem i have now is that my M2 channel is not working like in one of the previous posts. It seems i have a short on the lower pads (i guess)..

Almost certainly the issue is a short on the motor driver chip M2 during reflow. This is not hard to do, and I have done it myself on occasion.

If i manage to remove the chip, is it still usable after the short?
Good question, and I don't actually know. When I have done this I have not wanted to risk more work so I replaced it with a new chip.