I'm working on a project to create an arduino-controlled turbidostat, based upon the design found here: Evolvinator - OpenWetWare. (Though with many tweaks and changes of my own for the particular setup I need). I'd finalized the circuit and gone ahead to make a shield for my circuit. The shield stacked on top of the Arduino Mega, with a 12v external power source (through the barrel jack) works perfectly fine. However, when I try to stack an Ethernet shield in between the Mega and my pcb, the voltage regulator on the Mega massively heats up; I've searched around and seen that this is a known issue when using the Mega and Ethernet shield on a 12v power supply. The pinch valve and heaters I am using both need 12v, and in my pcb they draw this power from the VIN pin. I'm aware that I could create a new pcb that has a power jack on it and simply use a 9v adapter to power my Mega, but I'm wondering if there's any way to make this work without having to make a new shield. So could anyone help me with one of the below solutions?
- I know I can power the Arduino by bypassing the regulator and plugging a regulated 5v into the 5V and GND pins, but what I don't know is if I can still plug 12v into the power jack after doing that and just run the 12v through the VIN pin without regulating it. In short, bypass the regulator but still run a raw 12V through VIN?
- I'm using an aluminum metal housing, do you think I could wire it to the regulator casing to act as a heat sink?
- I'm reluctant to but I suppose wire a lead each from my pinch valve and heater to the wall adapter itself instead of plugging them into my pcb for power, think this could work?
- any other more elegant solution?
Thanks again for all the help, I'd never have gotten this far without this forum, and sorry about the wall of text.