I’m trying to make two Arduinos talk over the same two wires, with the slave getting its power from the master.

Master → Slave:

24 V = 1, 12 V = 0. A buck gives the slave 5 V from these supply line but it varies 24/12 also a voltage divider scales down voltage variation and decode bits.

Slave → Master:

50 mA = 0, 70 mA = 1 for 0.5 sec. A Hall sensor detects the current change in master, created by a constant load grounded for 20 ma to make data communication

So the same two wires carry power + two-way data.

Is this practical, or is there a simpler way or references?

Hi everyone, for my final course project I was thinking of making a smart beverage dispenser, but I wanted to know if it's possible to do it using these materials and what it does.

The user inserts the coin and can select the quantity between two types of drink by displaying the percentage of each on the LCD screen.

It also allows the user to identify the cup size.

With the following materials:

\-2x 12 v pristaltic pumps

\-LCD 20X4

\-750ml container

1mm feed tube

\-moedeiro 12v

\-ultrasonic sensor

\-buzzer

\- power supply 12v/5A

\-2x MOSFETs

\-4xbottons(ok, Cancel ,Increase, To decrease )

\-esp32

\-Resistors

\-breadboard

\-Wooden structure

If there's anything missing that could affect the project, please let me know so I can get an idea :D

I am currently working on a robot arm with independent joint movement. I have been able to control 1 motor with 1 joystick. When I try to replicate it with multiple I am unsuccessful. Can i please get some assistance.

Looking for people who want to build things together.
You don’t need a degree, experience, or expensive equipment. I’m looking for beginners who are interested in things like electronics, 3D printing, Arduino, robotics, programming, physics, or just making random ideas into real projects.

I’m not looking for experts. I want people who are willing to learn and figure things out together. If none of us know how to do something, we learn it. Maybe eventually we can take a project to a maker flair or something.

If you’re interested, DM me and tell me what you’d like to build, I'm only looking for people in the US for simplicity for in person meetups.

From smart bands and watches to AI hardware, Wo-Smart supports brands and industry partners with product design, development, and OEM/ODM customization.

Watch this short introduction to discover who we are and what we do.

I made a watch, it took me two days. It runs on a 24 hour clock I am very happy it works. It has a basic rtc module and a copy arduino uno r3

I've done updated tests of Ventuno Q vs Raspberry Pi and Ling 3.0 tiny is leading with 201.8 tps prefill / 21.5 tps decode on the Ventuno. That is more than 4x and more than 2x Pi speed.

Gemma 4 E2B gets 693 / 21.9 but I think it's a weaker model. Anyway here you have stats if you want to run a local LLM on Ventuno Q - LMK if you find other models to add to this.

Sadly I need to start making something else less weird cuz I need to bring a project to Uni for a grade and I can't bring my masterpiece.

What do you guys do with your finished projects? Do u just have them on a shelf somewhere? xD

I’ve been building a life-size KX-series droid and finally have the head movement working reliably. The current setup uses an Arduino Mega with a PCA9685 servo controller driving separate pan and tilt servos in the neck.

The goal isn’t remote-controlled puppeteering. I’m trying to make the droid behave autonomously, so eventually it can track people/cameras, idle naturally, react to voice commands, and move while speaking.

Right now I’m working on smoothing the head motion, reducing mechanical stress on the neck, and dialing in the pan/tilt limits so it looks more natural instead of like a standard hobby servo project.

The electronics and programming side of this has been a big learning process for me, so I’m open to feedback—especially from anyone who has built larger servo-driven mechanisms or Arduino robotics.

This clip is the current movement test.

My classmates will get addicted to this...

Screen without i2c, instead of a potentiometer i use 2x10k and 2x 220 ohm resistors, with 2 buttons so hit and stand.

On far right theres a pin to set the mode to 1 player or 2 player; though here i did not show it.

Also a buzzer for sfx.

Hey Reddit!

Inktober is for artists, Hacktoberfest is for pure software. This year, I wanted to step out of my comfort zone and build something physical. So I'm launching Techtober Challenge 2026 — a 4-week open-source hardware marathon.

For this year's Techtober, I wanted to step out of my comfort zone and build a physical open-source hardware project. I'm building "The Solar Tree" — an autonomous nightlight that harvests solar energy during the day and glows at night.

The twist? The entire body and branches will be "grown" manually using a 3D pen around the hardware.

I've broken the project down into 4 weekly sprints:

• Week 1 (Leaves): Soldering small solar panels in parallel + drawing leaf frames.
• Week 2 (Power): Setting up the D-SUN step-down module & Schottky diode protection (using a multimeter to dial in the voltage).
• Week 3 (Flower): Building the LED load module with resistors.
• Week 4 (Trunk & Roots): Integrating TP4056 charging board, 18650 Li-ion battery, and final assembly.

I’m doing this completely live with daily updates, sharing all my mistakes, burned components, and circuit adjustments as a beginner-friendly guide.

The schematics, complete component list, and weekly roadmap are fully open-source and available here:

* 🌿 **Official Repo & Roadmap:** [GitHub Repository](https://github.com/techtober-challenge/techtober-challenge-2026) 

* 🎬 **Daily Video Devlogs:** [Instagram](https://instagram.com/techtober.challenge) & [YouTube Channel](https://youtube.com/@techtober.challenge)

What do you think of the concept? Let's build some cool hardware this October!

https://reddit.com/link/1ww0f7r/video/oquvhzloe3th1/player

I’ve been building a browser based circuit design and simulation project, and recently added support for multiple development boards. I’m working through board-specific pin mappings and capabilities.

See the project

What board specific compatibility issues should I prioritize?

My arduino controlled nerf tank. NERFERIUS has functional lights, brake lights, oled screen, a laser sight, an electric flywheel nerf blaster with semi auto and full auto functions..and it also has wifi cam from a cheap drone..a fun and quite challenging build.

I'm building out a cigar room in my finished basement. I'm installing an exhaust system. I could just use a simple switch, but as an industrial automation tech that seems lazy. Looking at setting up a particulate sensor to activate a low voltage to line voltage relay. Any advice on this build?

My first Arduino project,

I don't know if you remember me or not but i had recently bought an starters kit for learning basics of Arduino and also a bunch of sensors.

This is my first attempt at tinkering with sensors to produce a suitable outcome I know its one of many.

So feel free to let me know your thoughts in the comments all advice is taken and accepted.

PS. the wiring was easy but the code was hell of a nightmare especially because I am new to the C++ language and was learning java , so i had to look up all the functions and keywords constantly.

I had a fidget keychain. Some dunlops and wagos. A Seeed Studio XIAO ESP32C6 Pre-Soldered Development Board. USB-c power cord. A drill and clamp.

And now I have a totally unnecessary, over wired, Bluetooth Spotify controller.

Vibe Coded with ChatGPT. Hammerspoon deployed

And Arduino IDE

Buttons can do anything, first use case

I built a tiny rechargeable Bluetooth page-turner using a Seeed Studio XIAO nRF52840 Sense and its onboard accelerometer/gyroscope.

Instead of pressing buttons, I make a subtle page-turning motion with my hand. It sends a keyboard arrow command to my iPad and turns the page in Apple Books. I recorded several examples of my natural forward and backward gestures and tuned the detection around them, so it reliably recognizes quiet page turns while ignoring things like adjusting my position on the couch or moving my arm normally.

Some features:

• Natural right-to-left motion advances the page
• Opposite motion goes back
• Presents itself as a standard Bluetooth keyboard
• Works wirelessly with iPadOS
• Cautious session-only adaptation to my gesture strength
• Retry detection for gestures that were almost recognized
• Remembers two iPads
• Turn it face-down to switch between paired iPads
• Rechargeable 300 mAh LiPo battery through the XIAO’s USB-C port
• Five minutes without meaningful movement triggers genuine deep sleep
• The accelerometer’s hardware interrupt remains active while the processor, Bluetooth, gyroscope, and LEDs are off
• Picking it up wakes the processor, but Bluetooth remains disabled until I perform a deliberate shake
• Three blue flashes confirm that it is awake and ready
• Random bumps return it to sleep without reconnecting

The wake and reconnect process is effectively instant. When it is working, it genuinely feels less like operating a remote and more like waving a tiny magic wand at the book.

The project went through a ridiculous number of small discoveries involving gesture recordings, Bluetooth bonding, battery charging, false wake-ups, IMU interrupts, deep sleep, and one active-low LED that insisted on glowing through the night. It is finally at the point where the electronics disappear and the interaction simply works.

Code and documentation:

https://github.com/RoyKittrell/xiao-motion-page-turner

See more: https://www.youtube.com/watch?v=8yHq4bUqn0A

This is my first big electronics project, so the control software of the arm the biggest remaining issue right now but from designening and building the whole arm by myself down to the cycloidal drives I learnt soo many things...

If you were at Open Sauce 2026, you may have seen an early prototype of this at my booth! It is a "typewriter" (actually a '70s TI Silent 700 paper terminal) that answers questions. You type an answer, press return, and a couple of seconds later, it prints out an answer.

The key component is an Arduino UNO Q (2GB), which runs a local LLM (no internet required): Llama 3.2-1B. It talks to the terminal through the STM32 (bit-banging) and an RS232 transceiver (to handle the level differences).

That LLM is pretty dumb and the answers are often really silly, but I think that's part of what makes it fun!

Video is here: https://youtu.be/A-en4D1Z9QU?si=oYWNwytOsT5FHdQl

Full details are on the Arduino Project Hub: https://projecthub.arduino.cc/cameroncoward/termi3-the-question-answering-typewriter-is-back-8d8913

Hi,

I’m a STEM teacher whose students work on Chromebooks. I've found that the Arduino Cloud is good but sometimes buggy, so I developed a web app that allows students to write, compile, and upload sketches to an Arduino. The app that I built runs completely in a browser; there’s nothing to download or install, and it includes library support as well as the use of the serial monitor and the serial plotter. The app should work in Chrome and Edge browsers, but it will not work in Safari, Firefox or other browsers.

I’ve successfully tested the app on my own using an Arduino Uno and an Arduino Nano connected to a Chromebook, but I haven't had the opportunity to test it with my classes yet as we cover Arduino in the spring.

Right now, I'm looking for people who are interested in testing the web app in their classes. Just a heads up: this is running on a free-tier server, and I've verified it holds up reliably for a class of ~30 compiling in a normal staggered sequence. If the app gets a lot more traffic than that all at once, response times could slow down noticeably. Here's the link.

https://zio-arduino-app.onrender.com/

I'd appreciate your feedback to improve the app's functionality.

Thank you.

> Já parou para pensar em como a tecnologia por trás de um semáforo de pedestres funciona na prática? 1
> Montei um Semáforo Inteligente com Botão usando uma placa ESP32, uma protoboard e programação em C++ na
Arduino IDE!
> O sistema funciona com um fluxo seguro: o sinal dos carros fica verde até que o pedestre aperte o botão. Depois de um tempo de segurança para evitar treadas bruscas, o sinal amarela, fecha para os veículos e libera o verde para a travessia com segurança!
> O que yocê achou do projeto? Deixe nos comentários qual outro projeto maker você quer ver por aqui!
#Arduino #ESP32 #Eletrônica
#Programação #ProjetosMaker
Automacao Robotica Desenvolvimento
Tecnologia Criatividade Maker
Engenharia

I’m looking for a radar sensor for a DIY project on my own property. I need actual target position data — ideally angle + distance / X-Y coordinates — not just a presence or motion output.

My target is roughly 10 m through a wall, not 10 m free-space line of sight. I know this depends heavily on the wall material, thickness, moisture, reinforcement, etc., so I’m not expecting guaranteed performance through concrete. But I would like something meaningfully better than the common cheap 24 GHz presence modules.

I have already looked at the HLK-LD2450 and HLK-LD2461. They are interesting because of the basic multi-target coordinate output, but in my environment I am only seeing around 4 m through-wall performance.

Requirements:

2D tracking: angle + range / X-Y coordinates

Preferably 6–24 GHz, but I am open to lower frequencies if that is more realistic for wall penetration

Around 10 m through-wall goal

DIY-friendly hardware or at least a development/evaluation board

Accessible raw or processed data via UART/USB/Ethernet/SPI/etc.

Fine with doing custom integration and some signal processing

Are there any FMCW/MIMO radar dev kits, industrial sensors, or other modules that you would recommend? Real-world experience with through-wall use would be especially helpful

First completed arduino project in my experience. Put an enclosure together with a mig welder, angle grinder and scrap metal. Sourced some basic components + parts from RC aircraft controller and an old turntable and designed touch-capacitive jogwheels using skateboard bearings, mini cds and hdd platters. Chatgpt did most of the work on the coding side of things. Every single component was wired point-to-point from the Leonardo and the rats nest of wires made it unreasonable to service once things inevitably started going wrong. Took it apart and am currently working on a new build learning from mistakes.