Nice job.👍
Some advice: when routing a board, start with the mounting holes. It looks like the holes were an afterthought, and you needed to place them where there was room left.
Also, put a bypass cap on that poor STM.
You can add the hole as a mechanical part in the schematic, so it gets created immediately once you go to layout.
Yeah the mounting holes are absolutely an afterthought, but as this is going in a custom case and we wanted to get the car running as fast as possible I just threw 2 in where I could and then sent to JLC 😂
There are more caps on the back of the MCU PCB along with the 3.3v regulator. In total it has 3x100nF + 2x4.7uF for decoupling on the 3.3v side
You can export the board as a .stp file and use FreeCAD to design the entire case with electronics. Well worth the effort, as you can spot mistakes before you make them in hardware.
Yeah i would have 3D printed the case, but the car is a family project so my dad hand made a very nice wooden case.
In reality the wooden case fits better with the car, and the tester will follow the car around
The case has a set of points for the spark gap (and a place to put a spark plug to test)
Model T magneto can push 25v+ at high RPM, a couple of places of this being documented linked below
[http://www.mtfca.com/discus/messages/257047/291495.html?1338086883](http://www.mtfca.com/discus/messages/257047/291495.html?1338086883)
[http://www.mtfca.com/discus/messages/331880/373775.html?1373739034](http://www.mtfca.com/discus/messages/331880/373775.html?1373739034)
I would imagine that applying 30v on them for more than a few milliseconds could damage them, but the way the magneto works in these is that it pulses 16 (i think) times each revolution. So the higher the RPM the higher the voltage but the shorter the pulse.
This is also how the ignition system has a kind of auto spark advance, as the engine speeds up the voltage rises. This makes the coils spark faster (and advances the spark in relation to cam position)
model Ts don't have magnetos, a magneto generates the spark for the spark plug. Additionally while the generator of a model T can produce \~25V a resistor is in series to drop the voltage to about 12V at high rev.
depending on the flux it might be much easier to clean it with soap and water.
i found that out myself after struggling to clean a board when ethanol would just make it sticky and more difficult to clean. so i used some hand soap and water (and a toothbrush) and it went away with ease
Not really on this PCB. Here are the graphs I get when running the driver PCB with an Arduino nano
https://imgur.com/gallery/iONpRFM
The graphs are pretty clean, you can even see an unwanted double spark in one test.
As an owner of a 1919 model T who doesn't want to buy the ECCT I'd be interested in knowing more about your project and your car. Do you have a post about this over on MTFCA or a YouTube channel?
Sure, this is based on the FACT tester forum thread here : [https://www.mtfca.com/phpBB3/viewtopic.php?t=9072](https://www.mtfca.com/phpBB3/viewtopic.php?t=9072)
This is my own take on the design, current builds use Arduino (mostly nano).
This version is STM32 based and I am trying to make use of the better ADC that comes with it to get some better data. (i can already have %50 more sample rate vs the nano)
I linked the kicad files for my power / current sense / capacitor sense board at the end of the thread.
Im in the UK so getting a coil tested is problematic enough let alone owning a ECCT :D
Awesome, thanks for sharing those! I'll be sure to follow your progress. I also liked the other 3d printed stuff you did for your T. Keep up the good work!
Nice job.👍 Some advice: when routing a board, start with the mounting holes. It looks like the holes were an afterthought, and you needed to place them where there was room left. Also, put a bypass cap on that poor STM. You can add the hole as a mechanical part in the schematic, so it gets created immediately once you go to layout.
Yeah the mounting holes are absolutely an afterthought, but as this is going in a custom case and we wanted to get the car running as fast as possible I just threw 2 in where I could and then sent to JLC 😂 There are more caps on the back of the MCU PCB along with the 3.3v regulator. In total it has 3x100nF + 2x4.7uF for decoupling on the 3.3v side
You can export the board as a .stp file and use FreeCAD to design the entire case with electronics. Well worth the effort, as you can spot mistakes before you make them in hardware.
Yeah i would have 3D printed the case, but the car is a family project so my dad hand made a very nice wooden case. In reality the wooden case fits better with the car, and the tester will follow the car around
Those coils are designed for 6-12V not 30, if you put 30V you'll burn up the coil, also you need a load (IE spark plug) when your testing.
The case has a set of points for the spark gap (and a place to put a spark plug to test) Model T magneto can push 25v+ at high RPM, a couple of places of this being documented linked below [http://www.mtfca.com/discus/messages/257047/291495.html?1338086883](http://www.mtfca.com/discus/messages/257047/291495.html?1338086883) [http://www.mtfca.com/discus/messages/331880/373775.html?1373739034](http://www.mtfca.com/discus/messages/331880/373775.html?1373739034) I would imagine that applying 30v on them for more than a few milliseconds could damage them, but the way the magneto works in these is that it pulses 16 (i think) times each revolution. So the higher the RPM the higher the voltage but the shorter the pulse. This is also how the ignition system has a kind of auto spark advance, as the engine speeds up the voltage rises. This makes the coils spark faster (and advances the spark in relation to cam position)
model Ts don't have magnetos, a magneto generates the spark for the spark plug. Additionally while the generator of a model T can produce \~25V a resistor is in series to drop the voltage to about 12V at high rev.
depending on the flux it might be much easier to clean it with soap and water. i found that out myself after struggling to clean a board when ethanol would just make it sticky and more difficult to clean. so i used some hand soap and water (and a toothbrush) and it went away with ease
I'll give that a go tomorrow, worth a shot while waiting for the alcohol
Did you have any trouble with electrical noise? I made a tester like this and learned how intense the noise can be from these coils firing.
Not really on this PCB. Here are the graphs I get when running the driver PCB with an Arduino nano https://imgur.com/gallery/iONpRFM The graphs are pretty clean, you can even see an unwanted double spark in one test.
Looks great! PCB probably helps a lot. I haven't ventured into that much.
As an owner of a 1919 model T who doesn't want to buy the ECCT I'd be interested in knowing more about your project and your car. Do you have a post about this over on MTFCA or a YouTube channel?
Sure, this is based on the FACT tester forum thread here : [https://www.mtfca.com/phpBB3/viewtopic.php?t=9072](https://www.mtfca.com/phpBB3/viewtopic.php?t=9072) This is my own take on the design, current builds use Arduino (mostly nano). This version is STM32 based and I am trying to make use of the better ADC that comes with it to get some better data. (i can already have %50 more sample rate vs the nano) I linked the kicad files for my power / current sense / capacitor sense board at the end of the thread. Im in the UK so getting a coil tested is problematic enough let alone owning a ECCT :D
Awesome, thanks for sharing those! I'll be sure to follow your progress. I also liked the other 3d printed stuff you did for your T. Keep up the good work!