I'm working on a basic application with a microcontroller controlling several components including a:
- 12V DC pump (Darlington array)
- 12V PWM fan (Darlington array)
- humidity sensor (I2C)
- and LED controllers (SPI)
Online circuit can be found here.
I've setup and tested each component individually to ensure they work given my circuit. From there, I transitioned from breadboard stage to a more intermediate stage using a protoboard along with various wires soldered in the right place.
After placing everything into a small housing, I recently went to connect everything only to end up frying the microcontroller and the UBEC. Since all the components were previously working, I'm not certain exactly what caused it except for perhaps a short caused by my mess of wires on the protoboard.
I know general questions like this are generally not within guidelines, but I'm just looking for insight into whether I'm completely off the mark somewhere.
Per the comments I added:
- diode to protect the PWM pin on the fan (although I'm not certain I actually need this - I figured the circuit built into the fan would already have this type of protection; unfortunately their datasheets don't share the circuit)
- fuse on the +5V & +12V rail
- power description on fan & pump
- added link to schematic