I am a complete beginner and have a project with an Arduino Nano that controls a DF player and a small led strip. A bunch of buttons activate different functions and a potentiometer act as volume knob.
All was working fine, then i soldered it on a board and cased it, it worked fine until my second battery re-charge, then it started acting weird (the led strip lit up when charging) and the project stopped working - when plugging in the Nano to the computer to troubleshoot, the response i got on serial is 'Sh' so i believe it might not work anymore.
I had to cut the board wires, used a developement board so it is easier to plug in wires to the nano without solder, and re-did the wiring of the ground line through the buttons as it was previously soldered to the main board.
After powering it, it was acting weird, plugging in to the computer via a usb cable in addition to the power supply made it work fine, but then it got really hot and now when plugging the nano alone to the computer with USB, the chip heats up quickly so i believe i killed the nano too (serial output is fine but the chip heating up is worrying).
As i don't want to burn a 3rd nano, i did a schematic of the whole project (attached) to get help on what i should change on my wiring/overall electronics.
There are few things i am really unsure about
Is the ground line through the buttons a valid option? (i checked with the multimeter and both side of the buttons pins seems to be connected)
I noticed on the behaviour of the project that i inverted polarity on the potenciometer (i fixed it in the code to invert the reading and have volume up when turning right, but wonder if it might have negative effect on the eletronics)
I moved the switch, it was between the battery + and the TP4056 before, now it is between the out of the TP4056 and my step up module, so the whole circuit is not connected when i re-charge the battery (i am wondering if this is what might have killed the first nano during charing)
Note : it is my first time using easyeda , the component are mostly accurate but the MT3608 might be unclear, it is a DC_DC step up 1A that i configured to output 5V (i checked the output with a multimeter).
Any help on what i did wrong / should change would be greatly appreciated
Thanks a lot, so in that case, if i re-write like below would it be ok?
All grounds to one line that connects to pin 24
Step Up module tuned to deliver 7V (or should i rather put it higher?)
Power for LED strip and DFplayer from the 5V pin of the Nano
With that setting, can i have the whole setup powered by the battery and plug it to the computer via usb at the same time if i have to troubleshoot code (as it will also be powered via USB in that case) , will it be dangerous for the nano?
What about the inversion of polarity on the potentiometer, is it ok to keep as-is and to invert the reading value in the code as i did?
Finally, you said the nano might still be ok , it seems like it when plugged to the computer as i have the correct serial log messages, however i am a bit concerned by the way the chip heats up (after 15 sec i can't touch it with my finger without burning myself) is it fine for the nano chip to get that hot?
Step Up module tuned to deliver 7V (or should i rather put it higher?)
At least 7.5V
With that setting, can i have the whole setup powered by the battery and plug it to the computer via usb at the same time
NO. Is this a classic Nano?
Finally, you said the nano might still be ok , it seems like it when plugged to the computer as i have the correct serial log messages, however i am a bit concerned by the way the chip heats up (after 15 sec i can't touch it with my finger without burning myself) is it fine for the nano chip to get that hot?
Is that with nothing else connected to the Nano?
If yes, then there is a problem with the board.
Ok so what should be the right way to power the whole thing, battery with step up to 7.5v to power the nano and then a step down module to bring it to to 5v to power both the dfplayer and the led strip?
It is a nano clone, so i believe if i can't have battery and usb for troubleshooting code, i ll just need to power the nano via usb and the other modules via battery for troubleshooting.
Finally the nano heats up without anything connected (just the laptop usb) that's why i think it might be damaged.
Use two boost converters, one to 7.5V or 9V for the nano Vin and one to 5V for the LEDs and DFPlayer.
For the nano boost, try to find one that is rated for 1A or 2A at the most A regulator rated for 5A or 10A won't regulate as good at the lower currents.
How many 18650's are there, wired in series?
Did you charge the batteries while in this circ uit or in a seperate charger?
The heat is the Voltage Regulator wasting energy in the form of heat.
When you say two boost converter, that would be something like this correct?
I have one spare, so i should be able to re-wire all up like this, they are rated for 1A and hae adjustment for output voltage (2-24V) so it would be fine with the settings you mentioned.
there is only one 18650 cell of 3000mAh, and the TP4056 module has circuit has several protection (against discharge, overcurrent / short cirtuit, and overvoltage)
I would connect the pot to the 5V output of the Nano, it's safer then the output of the buck. Also I think the DFplayer need a resistor in the TX line.
The DFplayer need a 1K resistor in the RX line.
A 220 ohm resistor in the Din line to the LED strip is usually recommended as well as a 100uF capacitor from 5V to ground.
