I am currently working on a project that requires a 12V RGB led strip controller. basically this is the controller:
Please note that I am using a raspberry pi 2 and that the pins in this diagram does not exactly match mine, but the principle remains the same.
I built the controller on a breadboard and everything went great. I then transferred the components to a proto board and connected it to my power supply. Nothing was booting.
Upon rechecking, I noticed that I accidentally swapped the input of the 12V power supply applying positive to ground and ground to positive. Hence, I pushed 12V+ into the ground pin of the pi. All my other components are also connected to the same ground pin. These components are:
37.xxx mHz timing crystal, DS1307 chip, MCP3008 ADC chip and Force sensitive resistors
When I fixed the wiring, the Raspberry pi booted as it should and it seems like everything is working except for the Force Sensitive resistors (problem could be with the FSR or the MCP3008 ADC chip or my brilliant soldering skills on the proto board which I think might be the main problem) and the LED strips (problem here can be the transistors or once again my soldering. I already tested the strip and that works). It also seems that my RTC module that I built with the crystal and DS1307 chip works and keeps time. This is also running on the same ground line as what the 12V+ was applied to. So I don't think the ground pin will be damaged.
My question is this: By swapping around the 12 v as in the diagram below, could I have damaged the transistors (which can take up to 16V, but thats when it goes into the right input I guess) or the ground GPIO pin on the PI? I might be wrong but when swapping these two terminals accitentally, is the circuit actually complete for the 12V as it is going into the transistors?
Can I test if the ground pin (or any other pin for that matter) has been damaged by applying an led and resistor between 5V and that particular GND pin and if the GND pin is damaged, will the LED light up? I can also use my DMM to read the voltages.
If anybody has some tips around how I can test this, or know if I certainly did kill my precious ground pin, please let me know. Your valued input is highly appreciated.