I tried to test my circuit that i put inside the casing, but there was some problems with the step up booster to make the 4v from my 2 parallel18650 into 5v.

However, two of my step ups randomly jump to 20v for a while and then will jump back to exactly 5v, and after a while 20v again. I tried another step up, and that one won’t go down below 10v. I thought that its probably my circuit drawing too less power causing the booster to be unstable, so i added a 470 ohm resistor to the outputs. It still didn’t work after a while.

I was very confused and forgot to pull out the resistor out of the malfunctioning booster that was at 20v…. the parallel 18650s made it even worse. So then I smell something burning. I didn’t know that it was the resistor burning, so I just took the resistor off with my fingers, and I got burnt. D:

But later I found out that its actually so dumb. I wasn’t sure if my step ups were working at first so I didn’t fully secure the battery wires into the terminals, so in case something went wrong I can just immediately pull the power source out. However, the bad connection of the wires with the terminal made the step up really unstable, causing it to jump to random high voltages. So I guess by being more carefull I actually ended up worse…..? Ok I see. :D

Also most of my circuit was connected to the step up (thats even dumber), and the 20v fried my conductivity module, and I think maybe my sensors too but I still need to check (fingers crossed). T_T very cooked