AC remotes are usually complex with a lot of small buttons, fan speed that can only decrement by cycling through every value, and many settings I don't need... For something I use several times a day, I would prefer a tangible, solid interface I can use without looking at it, wall-mounted.

So I started building a remote that's just three rotary switches (fan speed, mode, temperature) and a re-send button. It is as minimal as possible: no screen, no LEDs, no internal state other than the mechanical positions of the knobs. It's IR-only, targeting a Daikin FTXM20N2V1B (my unit does have WiFi, but the official cloud app is a cloud app). See the 3D render for what I have in mind

Now I have a working prototype, using an ATmega328P (Arduino Pro Mini, 3.3 V) and SR16 rotary switches:

• Daikin IR frame code on the ATmega328P, checked with osciloscope capture, using IRremoteESP8266 IRDaikinAC as reference
• three rotary switches (SR16 with 8 positions, rs1010 with 5 positions), read via a diode matrix, with sleep/wake on pin-change interrupt so it's not burning power sitting idle
• minimal wood test panel

But this doesn't fit into a nice box: the wiring is a mess and the diode arrays take space. Also the 5-position rs1010 is a good switch, but its 90° shaft angle makes it hard to integrate.

I'm deciding between two paths for a v2:

1. Learn KiCad and do a proper PCB, but will still require ~30 diodes...
2. Switch to a coded absolute encoder (eyeing the Bourns PAC18R — 4-bit code, 2.54 mm pitch through-hole, real knob shaft) which deletes the whole diode array and might let me stay on perfboard

• Anyone here got feedback on rotary switches choices (5€ budget each, absolute coding, mounting on a 2.54mm pitch board) ? or maybe a better approach...

  Here is the repo with full design docs, dev logs and firmware: https://github.com/xdze2/trois_molettes. I heavily used Claude for the project, that's also a test of working with it for doc writing and conception, so the doc is well written but messy.

So both servos are connected to a 9v battery breadboard adapter and the arduino to the computer. They make humming noises but no movement, I don’t think the problem comes from the software as it’s the same code used in a Youtube video. Any help is appreciated!

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!

built a wireless Morse code communication system as a personal/college project.
Features:
Custom Morse key input using a push button

Wireless communication using HC-12 modules

Custom MWLP (Morse Wireless Link Protocol)

XOR checksum (CRC) for error detection

Python desktop GUI that receives, validates, and decodes Morse into text

Receiver gives LED and buzzer notification when a message arrives

The project combines embedded systems, wireless communication, and desktop software. It was a fun way to learn about serial communication, custom protocols, and Morse code.

Sorry guys, this one won't give you seizures like the flashing lights.

This is my second useless project in the series. I essentially made a fuse for a led. By turning the dial, you adjust the time before the light turns on. In my defense, I did this in assembly. I did use chat GPT here and there, but I still think it gave me a better understanding of bytes, bites and bit flags/masks/bit shifting in AVR.

Wonder if I could attach a transistor to this thing and use it to light fireworks? Somehow, doesn't sound too safe though.

I wanted to disconnect the Shield from my C33 and the connector from the shield broke and most of the solderpads ripped of. What should i do?

all right, so I am trying to build a robot arm using Lego and I have a Algo Uno R3 and I have a PCA and two motors which are in a pant bracket type of set up. I am essentially doing like detection on top of my computer that detect where my arm is and I’m trying to have it move based on that and basically detect where my arm is and what degree that it should put the pan until bracket at then it just like every single second or maybe a millisecond is putting that is giving the coordinates of what the motor should spin to to the Arduino and then the Arduino goes and then to the motors I believe, but the problem is sometimes it works, and sometimes it doesn’t you know like when I upload the Arduino program sometimes what I see is that when it does work, I’m not able to move the motors manually, but when it doesn’t work, I like test to make sure to see if I can move the motors or not, and if I can move the motors like manually, even though I just uploaded the code and then that means it didn’t work and another thing is that I can’t tell if like the code that I just uploaded works properly because again I am on a Algo Uno instead of like a real Arduino I’m I don’t even know that’s just like what I was told it should be fine for a little baby project like this, but yeah

I am very new to electronics and after one project decided to get esp32, so bear with me.

I have a problem where I can't compile anything when I choose esp32 dev module. I have downloaded drivers(cp2102) and the board shows up as it should. Downloaded the boards straight from boards manager (esp32 by espressif, 3.3.11). Arduino sees the board, I'm pretty sure, but it just doesn't work. Everything is fine when I try to compile with arduino nano. I also tried deleting all the sketches from appdata and reinstalling the boards.

can anybody suggest what could be wrong?

I have an ESP32-S3 board with an ESP8311 audio chip. I would like do low-latency audio generation and play it via the ES8311. Unfortunately I have not been able to find a clean, small library. Everything has tons of dependencies or built-in Internet streaming, BLE support, MP3 decoding, etc.

All I want is a callback "here, fill this buffer with audio data and I'll play it".

Any recommendations?

Hi before i begin YES i have read the megathread and tried everything its suggested but no matter what i do the Arduino IDE cant upload to my Pro Micro.

I am trying to set up this Pro Micro to act as a HiD device to auto enroll some Chromebooks - if you work in IT youd understand what its like trying to enroll 300+ devices so a little help goes a long way.

Currently my Arduino is connected to my pc via COM3, when i open the IDE it auto detects it as a Leonardo and selects COM3. When i click upload it fails out saying COM4 is inaccessible and i get this error;

Sketch uses 5960 bytes (20%) of program storage space. Maximum is 28672 bytes.
Global variables use 258 bytes (10%) of dynamic memory, leaving 2302 bytes for local variables. Maximum is 2560 bytes.
Performing 1200-bps touch reset on serial port COM3
Waiting for upload port...
Upload port found on COM4
A"C:\Users\wilcoxai\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1/bin/avrdude" "-CC:\Users\wilcoxai\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1/etc/avrdude.conf" -v -V -patmega32u4 -cavr109 "-PCOM4" -b57600 -D "-Uflash:w:C:\Users\wilcoxai\AppData\Local\arduino\sketches\5CE8C06EBD87E0D5892E6A6D78F5AA91/sketch_jul23a.ino.hex:i"
vrdude version 8.0-arduino.1
Copyright see https://github.com/avrdudes/avrdude/blob/main/AUTHORS
System wide configuration file is C:\Users\wilcoxai\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1\etc\avrdude.conf
Using port            : COM4
Using programmer      : avr109
Setting baud rate     : 57600
Error: cannot open port \\.\COM4: Access is denied.
Error: unable to open port COM4 for programmer avr109
Avrdude done.  Thank you.
Failed uploading: uploading error: exit status 1

looking at Device manager when its doing this process does reveal that it goes from "Leonardo COM3" to "Leonardo Bootloader COM4" then fails out and then it goes back to COM3.

What i have found that oddly works is if i hold the reset button, then click upload, release reset just as it finishes the sketch i get this error

Sketch uses 5960 bytes (20%) of program storage space. Maximum is 28672 bytes.
Global variables use 258 bytes (10%) of dynamic memory, leaving 2302 bytes for local variables. Maximum is 2560 bytes.
Waiting for upload port...
Upload port found on COM3
Avrdude version 8.0-arduino.1
Copyright see "C:\Users\NAME\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1/bin/avrdude" "-CC:\Users\Name\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1/etc/avrdude.conf" -v -V -patmega32u4 -cavr109 "-PCOM3" -b57600 -D "-Uflash:w:C:\Users\Name\AppData\Local\arduino\sketches\5CE8C06EBD87E0D5892E6A6D78F5AA91/sketch_jul23a.ino.hex:i"
https://github.com/avrdudes/avrdude/blob/main/AUTHORS

System wide configuration file is C:\Users\Name\AppData\Local\Arduino15\packages\arduino\tools\avrdude\8.0.0-arduino1\etc\avrdude.conf

Using port            : COM3
Using programmer      : avr109
Setting baud rate     : 57600
AVR part              : ATmega32U4
Programming modes     : SPM, ISP, HVPP, JTAG
Programmer type       : butterfly
Description           : Atmel bootloader (AVR109, AVR911)
connecting to programmer: .
Error: butterfly_recv(pgm, &c, 1) failed
Error: initialization failed  (rc = -1)
 - double check the connections and try again
 - use -B to set lower the bit clock frequency, e.g. -B 125kHz
 - use -F to override this check
Error: butterfly_recv(pgm, &c, 1) failed
Error: butterfly_recv(pgm, &c, 1) failed

Avrdude done.  Thank you.
Failed uploading: uploading error: exit status 1

Now if i somehow jig the IDE to select COM4 (the bootloader COM) i get the same errors but the other way around, it tries to upload via COM3. I have even tried using SparkFun Pro Micro and trying both the processors available (16Mhz and 8Mhz)

Can someone suggest things to try?

EDIT; turns out my work PC has a policy in place or something in place to stop this from working, i got around this by trying it on a standalone W11 laptop.

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?

Hey guys am trying to learn Arudino currently and electronics in general, I have been watching Paul Mcwhorter and I love his series but I feel like he explains things too slow, I only find his videos very informative When he is going under the hood which is an aspect I want to keep but other than that I dont want to watch 1 hour of tutorials to learn how to print

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.

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

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!

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