Hey everyone,

Like many of you, every time I wanted to deploy a remote LoRa sensor node, I ended up with a bird's nest of wires. You know the drill: an Arduino or ESP32, a separate LoRa module, a buck converter to handle 12V/24V industrial power, and a bunch of discrete components just to read a 0-10V sensor.

To fix my own frustration, I spent the last few months designing ArduLora – a compact, ultra-low-power development board that puts everything you need for industrial IoT onto a single piece of hardware.

It’s completely open-source (MIT license), and I’ve just released the latest revision along with 3D-printable enclosure files.

What’s packed inside:

• The Brain: It runs on a RAK3172 module (STM32WLE5CC @ 32MHz). This means you get full LoRaWAN (Class A, B, C) and LoRa P2P right out of the box.
• Power That Makes Sense: It accepts anywhere from 5V to 24V DC via a terminal block (or 5V USB-C). No external step-down modules needed.
• True Deep Sleep: I added a hardware power gate pin (PB5). You can use it to completely cut off power to external sensors when the MCU goes to sleep, saving a ton of battery life.
• Industrial-Ready: There's an onboard RS485 transceiver for hardware Modbus RTU, plus two high-voltage analog inputs configured for 0-10V measurements.

The Software Side:
You don't have to learn a whole new toolchain. It programs natively in the Arduino IDE using standard functions mixed with the RAKwireless RUI3 APIs. I also published a helper library to the official Arduino Library Manager—just search for ArduLora and hit install.

Everything is up on GitHub, including schematics, pinout maps, and step-by-step example codes (covering everything from GPS integration and Modbus to deep sleep timers):

GitHub Link: https://github.com/NamNamIoT/ArduLora

I’m currently looking for ways to improve the hardware design for the next revision.

• How do you feel about the power gating implementation?
• Are there any other industrial interfaces or specific sensors you wish were broken out on a board like this?

Would love to hear your thoughts, critiques, or any feedback you have!

I made a super simple graphics editor as a weekend project. It runs right in your browser with no login required, generating u8g2 or XBM code for you. I hope it helps anyone using mono displays with Arduino.

https://github.com/niklauslee/empix

Has anyone had problems with Waveshare's 5.79" display specifically, or a similar problem with any Waveshare product?

Each partial refresh of the display only updates the bottom-left quadrant. A full screen refresh is possible, but only with the attendant flash pattern which isn't workable for a reader application.

When I run through Waveshare's test sequence, only the bottom-left quadrant responds to the partial refresh segments of the test (like the running clock) - when the display goes for a full refresh (like the black screen + test fields, the manga image) it updates correctly (at the end of the cycle, only the bottom-left quadrant again refreshes as you can see below).

I'm currently trying to figure this out for a Raspberry Pi so it's not an Arduino project, but I'm hoping someone here might have found a transferable solution.

I'm not a good enough coder let alone display-understander yet so I used Claude Code to test what might be going on (after eliminating mechanical/electrical user error).

The diagnosis from Claude Code - paraphrased - is that it might be something to do with the OTP waveform which fails to update the display fully. It wrote some code to test a substitute waveform table ("via command 0x32, then refreshing with 0x22=0xC7 or 0x22=0CF") which updated the full display successfully with a custom test image, but also with the flashing that comes with a full update.

Setup: Raspberry Pi Zero W 1.1, Pisugar S Plus, Waveshare 5.79" raw panel, 792×272, B/W + 4-grey; Waveshare e-paper HAT Rev2.3 connected with the wire loom to GPIO headers. Driver is waveshare_epd.epd5in79 - current as per Waveshare's github.

I've seen and tried to adapt some fixes which I found via search - such as this which hypothesises that it's a buffer update https://thoughts.gohu.org/posts/2025/epaper-partial-updates/ or the GxEPD2 library for Arduino, but neither has worked.

Any help would be very welcome, thank you.

I can't find pinout for this touchpad. I want to connect it to Arduino. Please help me find +5V, CLK, DATA pins.

So im buliding a GPS collar using a NEO-6M , im using a SIM800L for connection so its functional in rural areas as well where there is no wifi. im running on a 3.7v lip battery, my sim800l needs 5v sl im running it through a mt3608 stepup converter. But when i power it on the SIM800L fast blinks. And it says “NO SIM DETECTED “ Through ardiuno IDE can someone help?

Our school is teaching how to use arduino uno using c++ as the language. Thank you 😁

The frame rate extends to 72 FPS upon deactivation of the FPS limit.

# Hardware:

ESP32-WROOM-32 520kb RAM

ST7789 display (salvaged from keypad phone)

MicroSD card for ROM

# Firmware:

Anemoia-ESP32 (open-source NES emulator for ESP32)

# GitHub (my fixes): https://github.com/rkindustriesYT/Anemoia-NES-Emulator-fixes

# Shim06/Anemoia-ESP32:

https://github.com/Shim06/Anemoia-ESP32

Can anyone tell me a general road map of how to learn an Arduino? I decided to punish myself and picked a robotic experiment for my capstone but I have absolutely ZERO experience in anything electrical and Arduino stuff. Could you guys help me with a roadmap on what to learn first? I'm honestly so lost since I've been watching YouTube videos and I still ain't getting it.

I wanted to use the transistors as switches to turn the motor on and off. But when I actually tested this out it didn't work. I am aware that the second transistor is unnecessary and the circuit works perfectly fine when I connect the motor directly to ground. However, I wanted a way to cut the motor's connection to ground as well so I could make another similar circuit but in reverse to revert the rotation of the motor.
I am using:
A 9V battery as the power supply
BC547 transistors
Arduino UNO R3
3V DC motor
1k ohms resistors
I am new to electronics and still don't understand much about transistors so I would appreciate an explanation to why my circuit isn't working. Thanks!

(I’m aware some wiring may be wrong in this photo)

I’m making a simple robot that only drives and is not at all autonomous. It uses 2 dc 12v motors connected to screw terminals in a l298n motor driver( which does not say 5v-EN although the description said it is fully functional) The MCU I’m using is an unbranded uno r3 which only has one 5v header and 3 GND. The only 5v header is being used by a hc-05 used to make it wireless so none are free. The 11.1v battery will connect into the 12v and GND on the motor driver.

How can I power the rest of the parts without extra soldering or extra parts/batteries (not including splitters etc. as I have some of those already)?

I have been working on a button box project for a while but hit a wall when it came to programming. I wanted to keep it only in Arduino IDE seeing that there was more control on it. Somehow the base library doesn't work on my PICO as it only gives a 1 non stop even when other buttons are pressed, any help ?

Code:

#include <Keypad.h>

const byte ROWS = 2;

const byte COLS = 6;

char keys[ROWS] [COLS] = {

{'1','2','3','4','5','6'},

{'7','8','9','A','B','C'}

};

byte rowPins[ROWS] = {0,1};

byte colPins[COLS] = {2,4,5,6,7,8};

Keypad customKeypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup(){

Serial.begin(115200);

}

void loop(){

char customKey = customKeypad.getKey();

if(customKey) {

Serial.println(customKey);

}

}

Hello everyone, first post here.

Over the past few weeks, I've been working on my first ESP32-S3 project: a standalone RFID access control system. Once it's set up, it runs entirely on its own and only needs Wi-Fi occasionally to synchronize the time over NTP.

It uses an ESP32-S3, a PN532 RFID reader, a 16×2 I2C LCD, and a buzzer. I also wrote a Python CLI to manage the user database from a PC.

Some of the things it can do:

- Store up to 70,000 RFID users in a fixed-width binary database on LittleFS

- Import, export, and synchronize the database from the Python CLI

- Sync only the records that changed instead of retransferring the whole database

- CRC32 integrity checks for every record and for the entire database

- Badge expiration based on NTP time

- Admin badges for management tasks

- Automatic lockout after repeated failed badge scans

- Interactive CLI with batch operations and binary transfers

One of the biggest challenges wasn't the RFID hardware itself, but designing the storage layer and synchronization protocol. I wanted database updates to scale well even with tens of thousands of users, so I ended up implementing a binary database format, integrity verification with CRC32, and a sync mechanism that transfers only the records that actually changed instead of rewriting the entire database.

It's fully open source if anyone wants to check it out or build something similar:

https://github.com/Hyacinthe-primus/RFID_Access_Control

I'd love to hear any feedback or suggestions. If you spot something that could be improved, or if there's a feature you think would make the project better, let me know.

Here is the screen that will be used for my next project: the Megaplay! It is controlled by an Arduino Mega2560, which imposes significant constraints in terms of RAM and pixel transmission speed via SPI.

Regarding RAM, I couldn't use a second framebuffer. Only the textures are stored in memory. This made transparency handling more complex. For example, when a character has transparent pixels, the program needs to determine what is behind those pixels. Since the previous image is not stored in a framebuffer, it has to retrieve this information from the objects present in the scene, such as the position and texture of the trees.

I also implemented a palette system containing 16 colors. The colors are stored as 4-bit indices, and their 16-bit RGB565 value is then retrieved from the palette. This significantly reduces the amount of memory required to store the textures.

Finally, the limited SPI bandwidth makes it impossible to refresh the entire screen every frame. The solution I chose was therefore to update only the necessary areas and to adapt the games to this limitation.

Is it possible to salvage a Thermo printer like this one depicted here to use with an Arduino Uno to print unformarted plain text?

I made this a few years ago but now it is no more.. want to make another but improved version maybe.. share your projects and ideas. cheers!

Can anyone give me ideas on how to win this, and make a striking ideas on this Arduino project? Because I am expecting other countries that is better than us, and it is freaking me out... Thanks!

I made a gripper and xz axis for automating a record player like a jukebox. I'm using my LP60X turntable and servos to push the buttons. There's space for 30 records when the stack is on and it can flip the records too. I have a sensor to add in to detect when the tonearm returns to signal end of record.

Some bits need strengthening and the gripper leadscrew a bit of a lube. Could do with speeding it up and working on the noise too.

I'm only trusting a record I dont like with it at the moment 😅

Arduino mega

2x NEMA 23s with brakes on DM556 for CoreXZ movement

2x NEMA 17s on TMC2209s for gripper and rotate

4x servos for turntable buttons

This device detects motion and sends instant messages to a Telegram bot. (You can find tutorials on how to create a Telegram bot on YouTube).

GitHub source code: https://github.com/nixnika17/room.security-telegram.bot

• Code: C++ / Arduino Framework (ESP32)
• Assembly details (YouTube): www.youtube.com/@nixvaslgen
• Wokwi interactive simulation: https://wokwi.com/projects/470166740657591297

Hi, I am trying to use the Nano ESP32 to record audio, but I can't get the mic to work.

I have tryed fixing it by doing what was suggested on Arduino forums (like this one), but no luck. Attached is the code I have been trying to run, as well as an image of the connections.

The main issue is that I am getting a noisy plot that does not react to noise. I have tryed using 3 different mics and non of them work, I am guessing this is either an Arduino or a software issue. Any help is appreciated :).

#include <driver/i2s.h>


#define I2S_SD GPIO_NUM_21
#define I2S_WS GPIO_NUM_17
#define I2S_SCK GPIO_NUM_10
#define I2S_PORT I2S_NUM_0


#define bufferCnt 10
#define bufferLen 1024
int16_t sBuffer[bufferLen];


void i2s_install() {
  const i2s_config_t i2s_config = {
    .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX),
    .sample_rate = 44100,
    .bits_per_sample = i2s_bits_per_sample_t(16),
    .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
    .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_STAND_I2S),
    .intr_alloc_flags = 0,
    .dma_buf_count = bufferCnt,
    .dma_buf_len = bufferLen,
    .use_apll = false
  };


  i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
}


void i2s_setpin() {
  const i2s_pin_config_t pin_config = {
    .bck_io_num = I2S_SCK,
    .ws_io_num = I2S_WS,
    .data_out_num = -1,
    .data_in_num = I2S_SD
  };


  i2s_set_pin(I2S_PORT, &pin_config);
}


void setup() {
  Serial.begin(115200);
  delay(1000);


  xTaskCreatePinnedToCore(micTask, "micTask", 10000, NULL, 1, NULL, 1);
}


void loop() {
}


void micTask(void* parameter) {
  i2s_install();
  i2s_setpin();
  i2s_start(I2S_PORT);


  size_t bytesIn = 0;
  while (1) {
    esp_err_t result = i2s_read(I2S_PORT, &sBuffer, sizeof(sBuffer), &bytesIn, portMAX_DELAY);
    
    if (result == ESP_OK) {
      int samplesRead = bytesIn / sizeof(int16_t);
      
      for (int i = 0; i < samplesRead; i += 4) {
        Serial.println(sBuffer[i]);
      }
    }
  }
}

I consistently get one of the following upload errors:
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt X of 10: not in sync

This happens on both of my Arduino Uno boards.
Initially, I thought my old board was defective, so I purchased a new one from an online store. The new board uses an ATmega328P-PU microcontroller and an ATmega16U2 USB-to-serial interface. Unfortunately, both boards produce the same upload errors.

I'm only trying to upload either the built-in Blink example or a blank sketch, so the sketch itself shouldn't be the problem.

I've spent several hours searching online and trying different troubleshooting steps, but nothing has worked. I'm honestly running out of ideas and would really appreciate any help.

System information
Operating System: Windows 11

Arduino IDE versions tested:
1.8.19

2.3.4

2.3.10

What I've already tried
Used different USB data cables.

Tried different USB ports.

Tried another laptop.

Verified that Arduino Uno is selected under Tools → Board.

Verified that the correct COM port is selected (e.g., COM7 showing as Arduino Uno).

Changed the Windows-assigned COM port number (e.g., COM7 to COM9, COM10, COM11).

Reinstalled the Arduino AVR Boards package.

Performed a loopback test, which passed.

Confirmed that no Serial Monitor or other application is using the COM port.

Pressing the RESET button causes the built-in L LED to blink three times.

Tried manually pressing RESET immediately after compilation finishes and uploading begins.

Attempted to burn the bootloader using one Uno as the programmer for the other, but I couldn't complete the process because neither board can communicate successfully.

Is there anything else I can try? Since the exact same issue occurs on two different Arduino Uno boards—even on two different laptops—I'm starting to wonder if I'm overlooking something or if there's another possible cause.

ps: I can't confirm whether the old Arduino Uno was ever able to upload sketches successfully, as it was simply given to me. However, the other board is brand new and exhibits the exact same issue.

Update: The problem was the ATmega328P IC chip. Burning the bootloader didn't work, but replacing the chip fixed the issue completely. Thanks to everyone who commented and helped me troubleshoot. I really appreciate all the advice!

So I was making a SMARS robot, and I am having issues with the HC-05 module. So when I connected the module to my arduino(without the l293d shield) and connecting the TXD and RXD pins, it works fine, the text I am inputting in the bluetooth serial monitor is returning, meaning the module is working fine. However, when I connect the TXD to Servo-2 pin on the l293d and RXD to the Servo-1 pin on the l293d shield, the HC-05 pairs but does not connect and remote control does not work. I am using an actual Adafruit L293d, so can someone help? Have tried lots of things.
Mainly following this tutorial for the robot with some modifications btw(followed it for HC-05 wiring)
Thank you, and please help.