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Offline NS-21

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #165 on: January 09, 2020, 11:58:31 AM »
LukeZ, I can’t imagine what kind of person you are.

I seriously recommend inspecting your back in the mirror.

There should be wings with white feathers.


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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #166 on: January 09, 2020, 01:03:52 PM »
I can assure you there are no such things on my back!  ;D
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Offline Snipah

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #167 on: January 13, 2020, 02:27:54 AM »
Reading all this with interest can I ask a question regarding prototyping boards.
Before you rush off and have them made would 3D printing one to view in your hands help? At least with your dimensions and holes + its relatively cheap?
Just an idea!

Cheers Snipah :-)
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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #168 on: January 14, 2020, 08:24:17 AM »
Interesting question, but in my experience the cost of bare PCBs is probably no more than the cost of 3D printed part, and I'm not sure if the file formats would be the same in any case. Of course if you have a 3D printer laying about already then you could try it!
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Offline NS-21

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #169 on: January 14, 2020, 08:39:10 AM »
It seems to me pointless to prototype using a 3D printer.

My main mistakes in designing my version of TСB are unnecessarily large openings for connectors, and more functionality could be added.

It is only my fault and inexperience as well as inattention when designing a printed circuit board.

Of course, there are still errors from the technical point of view of the wiring of the conductive tracks, but I do not have the education to understand what I did wrong.

Ordering the first 10 boards, at the first registration costs incredibly little, thanks to the discount of the PCB manufacturer.

There are many ways to get this discount more than once ^ _ ^

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Offline NS-21

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #170 on: January 24, 2020, 06:03:08 PM »
Well, I soldered.
I start tests and study the settings.


IMG_1951.JPG
Testing TCB Firmware with Stock Arduino Mega IMG_1951.JPG
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Offline jhamm

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #171 on: January 25, 2020, 06:42:41 AM »
Look excellent!

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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #172 on: January 26, 2020, 06:35:51 AM »
Good job! I see you used a metal stencil, hopefully it wasn't too expensive. I always get the thin plastic ones since I know I'll inevitably change the design. :)

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Offline NS-21

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #173 on: January 26, 2020, 11:59:26 AM »
Stencil cost 7 USD.

Not so much money, and there was a big discount for the first order.
In the future, I am going to assemble a homemade plotter to cut a stencil for myself for free.
I really liked how easy it is to make a printed circuit board for your project, without much difficulty.

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Offline Lotuswins

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #174 on: February 04, 2020, 04:08:09 PM »
Hi Luke,

I'm still working on my home brew TCB, and have it mostly working now.  I just came across an issue though that I need help on. For the high intensity flash I have connected a BC327 transistor for Q9, which has a little lower rating than what the TCB has listed (.8 amp, 45v vs 1.0amp, 60v).  The flash had been working, using the latest LED flasher from Taigen, but stopped yesterday when I was confirming things were all good.  I tested the flasher on another tank, and it works fine.  I tested circuit continuity okay, and then for output but no trigger so I figure the transistor has broken down. 

I noted that this is a unique transistor (PNP) for the board, and am wondering why? and if perhaps the flash is needing a higher rated transistor? Recommendations for a through hole?

BTW, I changed the Q9 resistor too, from 150 to 562 as you recommended for the BC337's, I hope that is correct??

Thanks, Jerry
« Last Edit: February 04, 2020, 06:20:31 PM by Lotuswins »

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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #175 on: February 05, 2020, 06:36:55 AM »
Hi Jerry, you're right, that's the only PNP transistor on the board, the reason being the Taigen flash unit needs a positive trigger. NPN transistors are more common for switching things but the way they work is they switch the ground connection, we have to use a PNP to switch the positive voltage side.

I don't believe the current rating is an issue. I don't know for sure, but my best guess as to how the Taigen flasher works is that it charges a capacitor through the always-connected positive and negative leads. The third wire which we will connect to our transistor, is only the trigger signal that tells the flasher to flash. I highly doubt it carries very much current and it may not even be necessary to use a transistor for it, but we do so in order to protect the TCB processor as a matter of practice.

You checked the output of the transistor, but did you check the output from the processor ATmega2560 (ie, before the transistor)? That would let you know if there is a configuration/software issue rather than a transistor issue.

I have not actually tested this with through-hole components myself, so some experimentation is probably to be expected before we find the right values. With your BC337 I would think the 562 ohm base resistor should be fine, but you can try upping it to something like 1k and see if that makes a difference. The precise value is not critical but the higher the value the more current that can flow through that transistor. I actually don't know what current is required on the trigger pin of the Taigen flasher, but like I say I assume it is quite low.
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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #176 on: February 05, 2020, 06:43:08 AM »
I am just re-reading your post and I see you said "the latest LED flasher from Taigen."

I had not known they had a new kind of flasher! I just went and looked, do you mean this one: TAG120620?

I have never seen that before nor obviously tested it. I can only assume it functions the same way as the previous one, given that it would still need to be compatible with their same motherboard, but this is of course only an assumption. I wonder how it compares in terms of performance, as I rather liked their older camera-flash version...
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Offline Lotuswins

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #177 on: February 05, 2020, 12:24:03 PM »
Hi Luke,

Yes, that is the newer flash unit using LEDs instead of a neon (HV) bulb.  It performs quite well actually, and I was able to fit the LEDs and a 3mm IR emitter in tandem inside my IS3 barrel.  We'll see how it works, once I get the tank up and fully functional.

So on your recommendations, I tested the different resistors to the BC327 transistor on my test rig (I love this breadboard thing...I've been able to test a number of things on it, and with very minimal setup). 

Here are the results:

Resistor       Unloaded Vm      Loaded Vm      Flash (Y/N)

1k                2.85vdc             3.08vdc           YYY

562              3.25vdc             2.6vdc             YYY

380              3.31vdc             2.4vdc             YYY

270              3.34vdc             2.7vdc             YYY

Voltage is from Digital Fluke 115 with Max capture set on, on VDC scale.  Note all triggers flashed, indicating the transistor in the tank is obviously blown.  I perhaps damaged the junction when soldering??  It was working previously.  The strongest trigger is with the 1k resistor.  Captured voltages are not peak values so they are relative.  I guess I'll replace the transistor (ugh, its a tight mess of wires), and see if it will last. 

Yes, I checked the output of the ATmega, and it is at 5vdc and drops on the triggering of the cannon.


Thanks for the insight on the function, I'll let you know the results....Jerry       

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Offline LukeZ

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #178 on: February 05, 2020, 12:46:43 PM »
Well your test results are good, it shows that the circuit works even with the new Taigen device, and also that the resistor values are not critical, which I suspected. And even though you get a stronger trigger with the higher resistor, I'm guessing it makes no difference to the actual flash part, since the LED is powered by the little Taigen circuit. As long as it receives the signal to flash, it will do so with the same intensity.

We can only surmise what happened with your original transistor, but maybe when you dig it out you will notice something (possibly soldered backwards - I have done that many times). I really don't think it blew out due to use because the current it needs to switch is undoubtedly far below what it can actually handle.
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Offline Lotuswins

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Re: Testing TCB Firmware with Stock Arduino Mega
« Reply #179 on: February 05, 2020, 02:30:07 PM »
Hi Luke,

Well, that was painful!!   I replaced the transistor in question, and well, still no go.  So on to more troubleshooting which yielded a 27 ohm resistance to positive.....turned out a cold solder joint to the 5v bus....

Its all back working now, thanks for the help.....I must have jostled things when testing and the source voltage failed to provide a good pulse to the flash card.