I'm working on moving my breadboard "prototype" to a more permanent setting, aka a box. In order to do so, I soldered my components on a solderable breadboard then connected it to my NodeMCU. When I ran my program, pin D2 on my NodeMCU seems like it wasn't giving out any signal because when I measured the voltage from that pin it was giving out a negative voltage (which I interpreted it as not actually giving out anything..).
When I ran the program on my breadboard "prototype" instead of my permanent setting, pin D2 gave out a signal of around 3 ish voltage. Now granted it's a different NodeMCU.
Do you guys have any idea of what I might be doing wrong? Or is it just that pin not working. I tried pin D1 and D3 too, they didn't work either..
If you have read a negative voltage, re do the test again. Make sure the -Lead is on circuit common. If you get the same reading, again, then you have crossed wires/connection. Track down where the voltage turns from +V to -volts and do not discard minus voltage readings when dealing with +voltages. Those -volts tell a story.
Oh, and be ready for the MCU to be fried if a -V got into the MCU.
Updated: it's not the MCU problem. I took it out and use it on my breadboard prototype and it worked fine so it must be my soldering work or as you said, something about crossed wires/connection. Do you know where can I start with tracking?