Mechaduino overheats in minutes...

[Andrey V]

Hello!

I have some issue with my Mechaduino. It is very shaky in close loop mode no matter if PID parameters and A4954 driver overheats in minutes even with const float iMax = 0.3 @12V

Any suggestions? 

[Trampas Stern]

If it is an early revision of the Mechaduino the heat sink under the A4954 was never soldered as the heat sink had solder mask over it.  Some people would take chip off and scrape off solder mask and then solder it on correctly.   Even then the heat sink for the A4954 was not really good. 

The Smart Steppers www.misfittech.net, had a better heat sink. Additionally if needed you could put a thermal pad between motor and PCB to make the motor a heat sink but I have not found that anyone ever needed this option.  

The idea with the closed loop control is that when the motor reaches the desired location it should minimize the current into the motor, and heat on the A4954. Since your units is shaking then it is not converging and you never reach low current state.  This could be that the magnet is not glued well or that the unit is not calibrated well.  The smart stepper firmware has the ability for you to re calibrate and test calibration from LCD and/or USB, I am have not looked the mechaduino in years to recall how it's firmware works. 

Trampas

[Andrey V]

Oh, thanks. I got Mechaduino rev.02. Looks like it newest one. There is Mechaduino hardware support in Smart Stepper firmware. I tried to compile it for Mechaduino but finally it returns "SerialUSB was not declared in this scope" error. Can you point me where I can find any info how to tune Smart Stepper firmware?

[Andrey V]

And "'i2cid_str' was not declared in this scope using Arduino IDE 1.8.9...

[Trampas Stern]

Yea it has been awhile since I tried to compile for Mechaduino.... 

As far as tuning the PID it really depends on what you are trying to do.  A good place to start is just googling how to tune a PID controller:

https://robotics.stackexchange.com/questions/167/what-are-good-strategies-for-tuning-pid-loops

[Andrey V]

At second site it looks like board has some electrical issue. Finally it overheats in-predictably in any modes even in open loop. And looks like issues grown up. It sometimes cant past calibration and does not react on any commands except "s" and "d"...

[Andrey V]

And finally it is totally dead. Just flashing frequently with LED all the time. No firmware upload nor serial monitor... Rest in peace...

Little bit disappointed and unhappy.