Oh and i forgot to link the 2s BMS:
https://www.amazon.com/gp/product/B07KSQY67X/ref=ox_sc_act_title_2?smid=A323VFV6W4CN1S&th=1
Rather than read 21 posts
Hi, @cringymikolo
Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.
Thanks... Tom... 
2 Likes
That is a big problem, without the basics you will never understand what you are doing and that is apparent by your questions. Simple a but similar question if I have a rocket pointed at the moon will it get there?
1 Like
@cringymikolo - While waiting for parts... you can practice some simple sketches on wokwi.com - a simulator for Arduino and many devices, like servos, stepper motor, stepper driver.. . If you have questions, just ask.
1 Like
That seems really handy! I'm gonna check it out later.
Hi,
Still not a hand drawn schematic, but it will do for the moment.
Forget about the 9V converter and use a 5V type and feed it into the 5V pin.
This is more efficient and does not load the UNO WiFi down.
Tom..
Hi, @cringymikolo
This may help, I can't do a hand drawn schematic due to neuropathy, but a simple CAD produces this.
I hope it helps with how you layout your schematic.
Not seeing your code I just guessed about the step and dir pins.
Tom...
3 Likes
Thanks @TomGeorge that is a big improvement.
There seem to be a lot of different supplies; Wont the PCA9685 run from 5V?
Would it work if I take the 7.4V from the BMS and feed it into the VIN pin?
This looks way better than my paint sketch haha. Thanks for making it. I am questioning if I should buck down to 6v for the servo board like I planned or 5v, since I know the servos can handle 6v, but I'm afraid of voltage spikes. Also, maybe I should bms -> 12v -> stepper driver, bms-> 5/6v -> servo board, bms -> arduino (vin/barrel); or what I planned already, bms-> 12v -> stepper, 6v, and 5v
It should run from the batteries being bucked down to 5/6v, not the 5v pin from the arduino, right? Thats what I assumed since all the servo tutorial videos on YT warn to not power the servos from the 5V pin, only the board.
- Free
- Online
- pre-made Uno device
- image save
- remembers where you left off if you do not clear your chache
1 Like
Thanks for linking this, it'll be much better than using MS Paint for my sketches.
They all recently arrived. I can't power anything though because one of my batteries came defective, so in the meantime, I planned out the connections with the parts. I just used jumpers to represent the connections, but some will be soldered on (the BMS board, and the converters). Also, since the stepper came with just a regular wire, I think just splicing it with a jumper cable should work, like in the picture? This circuit hasn't been powered or tested, and the power to the Arduino isn't shown(neither is bms->convertor) because I don't know whether to use the 5v pin, VIN pin, or the barrel jack.
Thank you for getting and showing your lovely parts. Check one peripheral at a time using PC and Arduino. At the end, power your Arduino from 7V -12V Battery through barrel jack.
I'm currently trying to power just the Arduino, but my BMS board is only outputting 2.4V instead of the 7.4V I need. I've made the connections right, the batteries are full (~3.8v and ~4.1v), and I am providing an 8.4v charging supply to the P+ P- pins. Any idea why this isn't working?
(I haven't soldered the charging connection on yet, as I am not sure about that part of the circuit)
Hi, @cringymikolo
Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.
Thanks.. Tom...
Hello! I'd be happy to help you with your Arduino project. Unfortunately, you didn't provide the sketch or parts list in your message. Please share the details, and I'll do my best to review and provide feedback on your plan. If you have any specific questions or concerns, feel free to mention them, and I'll address them as well.