Comment by craghack
3 days ago
Well built and a great write up!
Addressing some of the comments/concerns in your documentation:
* To protect the ultrasonic mister from bad firmware frying it, you could probably replace R6 with a sufficiently sized capacitor to make an effective DC block
* I've also had issues with a thermal sensor just reading board temp, best solution is to make the sensor a separate board. Short of that, one can mill slots around it and reduce copper pour to reduce thermal conductivety from the PCB.
Thanks!
> To protect the ultrasonic mister from bad firmware frying it, you could probably replace R6 with a sufficiently sized capacitor to make an effective DC block
That is an excellent idea - I'll definitely keep that in mind for a future version.
> I've also had issues with a thermal sensor just reading board temp, best solution is to make the sensor a separate board. Short of that, one can mill slots around it and reduce copper pour to reduce thermal conductivety from the PCB.
I ended up just moving the sensor offboard and as far away from the heat source as I reasonably could. I did consider the milled slots + reduced pour option, but given the amount of heat generated by the LEDs, it seemed best to move the sensor further away.
Most of my time designing hardware is spent trying to find ways to prevent the doofus writing the firmware from releasing the magic smoke. I am that doofus