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confidential_

9/10/2025

Dedicated CC/CV modules for charging 18650 batteries?

I am not very familiar dealing with 18650 batteries. Its a very simple 3 cell 18650 in series managed by a HX-3S-01 BMS. I am planning to add USB C PD charging functionality along with smart battery charging features like constant current and constant voltage switching because thats how li ion batteries are supposed to be charged. There are readymade solutions like this https://www.amazon.in/Step-Up-Overvoltage-Protection-Charging-Applications/dp/B0FDRCMWT8 but they simply take in 5v3a usb input and boost it to 12v along with the cc/cv switching functionality to charge it which is not usb PD. I also found the XL4015 module that chatgpt sent me but isint that just a buck converter? so I have to manually change the settings instead of it automatically switching between CC and CV? or am i wrong?...

Tamerlan

9/8/2025

Matrix Wiring help

Hey everyone—looking for some advice. I’ve got six 128×64 flexible LED matrices and I want to run them as two channels, with three panels daisy-chained per channel acting as one continuous display. I tried a Raspberry Pi Pico with a HUB75 adapter and also an Adafruit hub, but ran into a bunch of issues. Not sure if it’s my wiring or the software stack. If you’ve done something similar, what hardware/driver stack would you recommend? Any tips on a reliable setup (controllers, level shifting, libraries, examples) would be super helpful. Happy to hop on a quick call if someone’s willing to walk me through it. Links to the exact parts are below—thanks! Full Color LED Panel, 128x64... https://www.amazon.com/dp/B0CH9BQTKW?ref=ppx_pop_mob_ap_share...

. . . AARAV . . .

9/7/2025

ESP 32 over voltage popping sound

so, I plugged my esp 32 into an power source, which is probably slow, the exact wattage is unknown, and then I heard an POP! The circut was on an breadboard, on which the rails were slightly Brocken, the esp 32 was connected to an separate dev board, which smells like an PCB cut in half (I’ve done it before) . So, I want to know, what got fried, if possible, and is it safe to plug in? The esp status led was always . The Esp32 is not hot, or smelly.

LGSNS

9/7/2025

PCA9685 16 Channel Servo Driver Power Supply

I'm planning on doing a project using 8 SG90 servos with the PCA9685. What li-po batteries (or any kind of external power supply) would you guys recommend?

Ryan Bardsley

9/6/2025

Portenta USB-C cable compatibility?

I am trying to incorporate a Portenta H7 Lite Connected as the main processor in a sensor I am building. I was originally placing the H7 in an enclosure with the USB-C connector integrated so a USB-C cable can easily be inserted into it. The sensor would be used by customers, and what I am finding is that there is (well, WAS) only a single combination of cables that I could get to work. The cable that used to work was a USB-C to USB-A adapter connected to a USB-A to USB-C cable that I connect to my new MacBook Pro. Because the Portenta H7 has a USB-C connector on it, any customer that is using my sensor will assume that any USB-C cable can be connected. This is not the case. So, to fix this, I created a USB-C breakout board that fakes a USB-2.0 4-pin connection using VBUS, GND, D+, D− only to communicate with the Portenta H7. This worked, but only temporarily. Having taken a week-long break from this project, the SAME hardware which used to connect my H7 + USB-C-to-2.0 PCB adapter to my MacBook Pro now no longer works. ...

Bananaman

9/6/2025

could anyone help me learn how to use a 8*8 Led matrix?

I looked online, asked chatgpt and other stuff for hours, and it doesn't want to work

Etienne

9/6/2025

Diy speaker

Hey, how can I make this work? I want to turn the earbuds into a speaker.

. . . AARAV . . .

9/6/2025

Relay Pinout

I have this relay, and I can’t seem to figure out the Pinout. The pin header pins are +-/s

vapor

9/5/2025

Need someone with a ESP32-S3 based board to help me debug a bare metal issue

I am working on a project targetting the ESP32-S3 on bare metal, but im having weird issues on real hardware, that don't happen in wokwi. I only have a M5stick s3 on hand, but wokwi is emulating a esp32-s3 devkit-c1. I'd appreciate anyone testing it on any esp32-s3 based board, and I'd love to accept pull requests to add more board support, even though the ESP32-S3 port of my project is extremely early in development. Here is a link to the project (the ESP32-S3 related code is on the "dev" branc...

Magig_33_gamer

9/5/2025

where to search for SMD part names

i got a broken UNO like d1 ESP8266 it just smoke off at a mesurment event the bropen part top right is a smd A6163k as coudt ident is this the DCDC converter 6-pins so23...

santi

9/5/2025

MAX30100 OXIMETER SENSOR PROBLEM:

hi, someone knows about oximeter (30100)? i have a big problem, that sensor gives me problems like: -doesn't recognize it, doesn't show me anything in the serial monitor -recognize it when i disconnect the ground from the sensor, but this doesn't make sense so, is bad...

Penguino

9/3/2025

Need Help Powering a project

Hello. by no means am I an expert in electricity and for my safety I don't want to buy some sketchy Step down module i found on eBay. Im trying to build a robot and he has 4 MG995 servos and 4 TT motors to drive him around using a mecanum drive system. However I am having trouble in two things. Finding a Battery to supply 6 Volts and/or finding a battery with the right Amperage. Now the total collection of Amperage during use is around 8 Amps. But if evrey motor stalls it might be as high as 12...

Stoneware

9/3/2025

problem with A4988 Driver

Hello, I just started playing with Arduino. I’m working on a simple project with a stepper motor. My setup is basically identical to this one: https://lastminuteengineers.com/a4988-stepper-motor-driver-arduino-tutorial/ The wiring is the same. The difference is that in the article they use an Uno, while I’m using a Nano and I am powering it by 12V and my code is simpler....

Tari

9/3/2025

ESP32-S3 Supermini Battery Power. TP4056 Alternatives?

Hi! I'm going to be using an ESP32-S3 Supermini for a Bluetooth game controller. I want to be able to charge the device and play at the same time, and also have the capability to work as a wired controller for devices without BT. Can someone recommend the proper charging circuitry for this? I've seen a few folks recommend TP4056-based units, but I want to avoid them as they can have problems with over-charging, over-discharging, and overheating (see: https://www.reddit.com/r/Gameboy/comments/ouq5by/psa_do_not_use_tp4056based_chargers_to_liion/). Space is limited, as I'm currently basing it around a SNES controller footprint; so I need something that isn't too big. For the battery, I'll most likely go with whatever pouch cell I can fit. I haven't decided on an exact one yet. A nice extra feature would be the ability to monitor the battery life in % on the device (It has a small screen). TLDR: I want to charge a LiPO and power my ESP32 with it, at the same time. How can I do this safely? ...

. . . AARAV . . .

9/2/2025

LM393 mic dev boards be used for Music Visualizer?

I have 2 LM393 mic 🎤 based dev boards, I want to make an 5 led visualizer, by taking the decibel the mic measures, and comparing it to a set threshold to turn on the LEDs. But when I tried the code, the mic was not picking up anything. I tried both modules, the codes de-bug points where not picking up anything displayed in the serial monitor, the connections where fairly secure. I need help determining if these modules can’t be used, or if there is something wrong with my code. Any help would...

hendr1x

9/1/2025

I just melted my ground wires and I don't know why :(

Pretty embaressed honestly. I just tried to create this simple circuit exactly... http://adam-meyer.com/arduino/N-Channel_MOSFET I'm hoping based off my pictures someone can spot what is wrong. I was running the board from usb, left that plugged in, turned on my benchtop power supply which as sending 12v to red, grounded is black rail on breadboard. I made one change in the photos...I disconnected one ground wire which was plugged in to the right side...other than that, everything is is exactly how it was setup when the error occured. Any ideas?...

hendr1x

8/31/2025

Using mosfet for the first time. Found two different approaches. Can someone explain differences?

Hello, I purchased P30N06LE (N-channel) to drive a 12v solenoid with my arduino. I found two circuits to wire it up and I'm not sure which is better/why they are different. Could someone explain so I can learn not just for this task but future projects? Thankyou.

Gabileotank 📎📎📎📎📎

8/31/2025

Troubleshooting Cosmicwatch's Muon Detector

So I recently finished building a muon detector created by Cosmic Watch (http://www.cosmicwatch.lns.mit.edu/), but it doesn't work. I am not getting any output on the OLED screen nor is the LED flashing. There are three main reasons why I think it wouldn't work: 1.) I used slightly different hardware on some occasions, because the original was unavailable (slightly different chip in terms of the name, but it apparently was just a newer version, still I will compare the datasheets to make sure the pin locations are the same); (slightly different resistors/capacitors, same resistance/capacitance, but different voltage or wattage values); ...

SMT_reference.pdf

sen

8/29/2025

dfplayermini is not communicating with arduino uno r3?

connections are right, rx tx are connected correctly, vcc and gnd are connected correctly, speakers are also connected. sd card has files in fat32 format (0001.mp3). #include "SoftwareSerial.h" #include "DFRobotDFPlayerMini.h" ...

daultimateboss

8/29/2025

Hey all,

I want to make a project that uses the Mouse Library. I have seen the following in the official documentation "These core libraries allow the 32u4 and SAMD based boards (Leonardo, Esplora, Zero, Due and MKR Family) to appear as a native Mouse and/or Keyboard to a connected computer". I also see that the arduino micro is based on some 32u4 board....

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Official Arduino Discord - Discuss all things Arduino!

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