Home Build
« on: September 19, 2017, 01:17:22 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

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Offline LukeZ

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Re: Home Build
« Reply #1 on: September 19, 2017, 02:46:24 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.
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Offline LukeZ

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Re: Home Build
« Reply #2 on: September 19, 2017, 02:47:21 PM »
Also as you build your boards please post over in the Assembling Boards by Hand thread to ask questions or share your experience.
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Re: Home Build
« Reply #3 on: October 05, 2017, 04:37:52 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
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OpenPanzer_TCB_Mk1.zip
(153.68 kB ~ Downloads: 21)
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Offline LukeZ

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Re: Home Build
« Reply #4 on: October 05, 2017, 10:54:01 AM »
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.

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.

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OpenPanzer_TCB_v1_r23_SEEED_Gerber.zip
(203.93 kB ~ Downloads: 18)
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ScoutESC_v1_r10_SEEED_Gerber.zip
(127.68 kB ~ Downloads: 20)
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OP_Sound_v1_r1_SEEED_Gerber.zip
(54.09 kB ~ Downloads: 20)
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