Mac restarts when potentiometer reaches MAX. External power 12V DC / 3000mA

Hi guys!

I’m new to this wonderful world of tinkering and until today everything has been going more or less smoothly…

I’ve connected a 12V DC / 3000mA to my Arduino Uno R3 through the external power plug - I need it for running a 5050 led strip. That part works fine, so I’ll leave that out. The problem arises when I connect a potentiometer (as shown on the diagram) and it reaches MAX - then it somehow makes my Mac restart (it is connected through USB).

I thought - with my very limited knowledge about electronics - that it might be some kind of back burst (?) and therefore added a diode (6A6 - http://pdf1.alldatasheet.com/datasheet-pdf/view/58862/DIODES/6A6.html), but this didn’t seem to solve the problem.

I burned a ATMEGA-chip earlier today and I’m down to my last so for once I don’t feel like experimenting toooooo much - any help is warmly appreciated.

Thanks,
Martin

Your pot should be across the 5V, not Vin.

MartinBollerup:
I burned a ATMEGA-chip earlier today and I'm down to my last so for once I don't feel like experimenting toooooo much - any help is warmly appreciated.
Thanks,
Martin

Your circuit is capable of sending up to 12 volts into the Arduino analog input pin when the maximum voltage should only be 5 volts (that's why you're burning out your AVR chips).

Connect the potentiometer to 5 volts and ground (not 12 volts and ground like you have).

Thanks a lot - that helped :wink: