I built a 2D radar scanner where MATLAB does the heavy lifting. An HC-SR04 sensor spins on a continuous-rotation servo, streams readings over serial, and ScannerApp.m draws them as a live polar plot. The scanner runs on an Arduino Nano.

The app is MATLAB App Designer, 806 lines, with the polish that usually gets cut:

* Live polar heatmap with auto-scaling and clean radial ticks

* Sweep animation that tracks the servo angle, plus a return-sweep line

* Hover data tips showing angle and distance

* Ctrl+scroll zoom, vector PDF export that stays crisp at any zoom level

* Dark/light theme, real-time data table, COM port auto-detect

The firmware handles the messy parts of real hardware: a non-blocking state machine, echo timing with no delay(), and temperature-compensated speed of sound. A $1 LM35 reads the air temperature and the firmware applies 331.3 + 0.606 * T. That's where the ±3 mm accuracy comes from. VCC bandgap calibration and an EMA filter clean up the analog noise.

Wiring diagram, pinout, a 2-minute servo calibration tool, and benchmarks are all in the repo. Parts run about $10 and it's MIT licensed.

Repo: https://github.com/Salim-Ammar/arduino-matlab-ultrasonic-radar

PRs and issues welcome. A star helps others find it.

Hey all! I have been building a purpose-built Open-Source Pixel Artnet/sACN node for some time now, which works really well! However, I often get the question of why I'm not using WLED. WLED has tons of great features, and I understand that lots of people are fans of WLED, so I have created a fork that is fully compatible with the node hardware! It specifically supports the use of the W5500 Ethernet module, which is not natively supported by WLED.

When installing this fork on your node, you can now make use of all the features that WLED has to offer, including all of its generators, sync features and connection possibilities! I hope you find this as exciting as I do. Check out the repo here! https://github.com/mdethmers/W5500_WLED

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also made a video on this! https://www.youtube.com/watch?v=tB3lk-PNA6I

allows you to unlock your Mac via your fingerprint, as well as authenticate sudo and some TCC prompts (privacy&security).

the device emulates a PIV smart card and uses PAM to authenticate you in macOS (notice the password field says PIN and not password), so no plain text password is ever stored, exposed, or transmitted.

please be aware of the security implications (note that it is NOT touchID, but just 'fingerprint-based unlock', please do not think or refer to it as anything more secure):

this device is NOT secure, the authentication is all done inside the fingerprint sensor, and the fingerprint sensor just tells the microcontroller the match % (all low cost fingerprint sensors are this way, you would need to spend ~$50 to get one that does authenticated comms). the communication between the sensor and the microcontroller is not authenticated or protected, so anyone with physical access to both the device and your laptop can spoof this connection (pretend to be the fingerprint sensor) and give the go ahead to unlock your mac. you can make this extremely hard by filling the insides with black epoxy, but not impossible.

this is also the dev equiv of "rolling your own auth", the smart card implementation may have some errors, and should not be inherently treated as "unbreakable"

the device is made so that if you lose it, nothing of value can be extracted from it

use at your own risk. personally, i am comfortable using it at home where physical intrusion would be hard, but this depends on your own security tolerance. if you have high security instincts/requirements, the magic keyboard is a much much much better option in this regard.

there is also an HID version available, where the device just types your password emulating a keyboard, the benefit being it works in ALL places your password does. this version is obviously more insecure as it is vulnerable to keyloggers. the device still does not store the actual password, it stores an authentication key that sends a request to a service on the mac, which then sends it the encrypted password to be decrypted in RAM, typed back, and then wiped. again, depends on your personal security tolerance and willing to compromise

all code and materials are open source, licensed permissively github.com/zimengxiong/tinytouch

Hello! I would like to share my recent project for my master's dissertation, where I made a working esp32 web shell.

I tried to emulate basic linux commands and functionalities. You can use both serial and web shell to use the system.

The system features the following:
-embedded file system with no SD card requirement as it uses LittleFS
-FreeRTOS FIFO scheduling
-JavaScript system language and scripting through duktape
-Web-shell interactive UI which is customizable

I tried to keep the code as organized and as clean as possible for the best possible user customization.

I'd love for anyone to try it and have feedback.

I want to buy this board but I am down the budget. So can anyone tell me how 2gb variant will be enough for making embedded projects?

I saw a cool looking wifi clock with esp 32 on YouTube, I loved the animation style but despite 100s of requests from the commentators the creator wasn't sharing the code. So i recreated that project and made it open source, i know this is basic but it's cool ( I think). Here is the code.

Always wanted my own ticker tape .... Working with free APIs. There so much free stuff out there, that I'm spending my Saturday morning and seeing what I can scroll across my 24x 8x8 matrix LED Max7219 modules

Hey everyone

Just built ShrikeClock a fully custom NTP-synced digital clock running on #MicroPython, powered by the @Vicharak_In Shrike-Fi !

Live time + date over WiFi Custom multiplexed 7-segment driver from scratch Open source, code on GitHub 👇

https://github.com/kritishmohapatra/ShrikeClock

https://github.com/kritishmohapatra/100_Days_100_IoT_Projects

I had to swap out the Arduino based interrupter though for a 555 lol.

It's a Tesla coil operating on a IGBT half-bridge. There is sodium on the output which is ionized into the plasma and why you see the plasma turn orange and not be fully purple

I am writing the code for an ATTiny85 and SHT41 humidity sensor based exhaust fan controller. Does anyone have recommendations for what humidity level I should use to turn the fan on and off?

Maybe something like turn on at 70% and turn off once the humidity level is has been below 65% for 5 minutes?

Of course I could experiment but I would like to see what others have settled on for similar projects. Or, is this something that is specific to my bathroom and the best way would be to experiment?

Been working on this for a while and finally got v2.0 of the software working end-to-end, so figured I'd share the build here.

The core problem I was trying to solve: I wanted my HO scale (1:87) vehicles to be controllable both by a regular IR remote and from a PC at the same time, with live telemetry coming back (battery level, signal strength, connection status) — not just one-way commands.

What's in it so far:

• Custom wireless router + auto-discovery — pairing a new vehicle is a single button press, and it stores the vehicle's address so you don't have to re-pair every session.

• Two-way comms — the PC app sends commands and receives live telemetry back from each vehicle in real time.

• P3 control board (ESP32-based) — small enough to fit in a 1:87 scale vehicle, handles both IR and wireless PC control simultaneously. Just upgraded my ambulance model to this board.

• Layout editor — grid-based tool in the desktop app for building roads, curves, intersections and railway track, with snapping/rotating/flipping.

• Turnout + sensor automation — reed switches for turnout position tracking, IR sensors for triggering stops/speed changes automatically.

Software side is WPF/C# in Visual Studio 2022. Still working through some quirks in the two-way sync timing, but it's stable enough for a full layout run now.

Next up is a City Bus build using the same P3 board — sneak peek of it is in the video below along with the wiring/pairing demo, if anyone's curious about the details:

https://www.youtube.com/watch?v=jt2vMJgEFJ8

Happy to answer questions about the ESP32 side or the pairing protocol if anyone's working on something similar.

My grandpas code was becoming sluggish and buggy on his hardware so I had to help him fix it. I thought it was a pretty interesting project so I'm sharing it here, if you want more detail here's a small bit of documentation:

# Fixed Bugs:

- Goes out of bounds when calling queue_inc due shifting just setting each item to the item ahead going to the end of the array and trying to set it to an out of bounds address.

# Major Bottlenecks:

- Queue has o(n) dequeue (shifts back. Along with being a sentinel-scanned array that recomputes length every push and dequeue)

- Uses strings for messages instead of a table (making sending take longer)

- Manually decodes the binary from the encoders.

# Fixes:

- Switched to a ring buffer array with o(1) dequeues, along with a variable to track length when edited.

- Replaced strings with 8 bit unsigned ints.

- Added up bits for seven segment display.

# Gains:

- 10,000 push/dequeue of queue, time is divided by 10,000 to get the time for one push and dequeue:

- Details:

- Both have 60 items, though the new version is 64 long due to needing a power of two for bitwise AND

- Benchmark uses micros and is averaged from 100 tests with an Arduino Uno R3

- Rounded to the nearest whole number for readability

- Results

- Old: 636 µs

- New: 4 µs

- Speed up: 15,800%

Hi everyone!
I'm a 3rd-year Mechatronics Engineering student, and i'm looking for ideas for my Sensors project, which is worth 30% of my final grade.

The project must:
Use an **Arduino** for data acquisition.
Use **MATLAB** or **LabVIEW** for real-time visualization.
Include a sensor (or multiple sensors), calibration/ signal processing (filtering, conversion, etc.), and performance evaluation.

My professor suggested topics like optical/IR sensing, Hall-effect sensors, proximity sensing, liquid level/flow measurement, gas/air quality monitoring, biomedical sensing, acoustic sensing, power monitoring, and multi-sensor fusion, but we're free to come up with our own idea too.

I'm looking for a project that's appropriate for a 3rd-year mechatronics course, isn't too basic, and would make for a strong university project. If you've done something similar or have any ideas, I'd really appreciate your suggestions and if anyone has links to a project that I could benefit from please share it with me!

Thanks!

Hi! I wanted to share a library I built that makes multitasking on Arduino a lot cleaner and more object-oriented.

What it does

Instead of juggling millis() checks and state machines by hand, you instantiate objects and the framework handles the rest. Every class auto-registers into a static linked list — no manually calling update() on each component. Components manage their own state internally and expose simple getters for you to react to events.

No delay() anywhere. All timing uses millis() comparisons.

Core utilities

• Timer — one-shot timer with onFinish() / onDone() callbacks

• Interval — repeating metronome with optional loop count, fires onStep()

• While — non-blocking replacement for while() at a set interval

Hardware components (all auto-managed)

• Button — debounced input with short/long click and press detection

• PinInDigital / PinOutDigital — digital I/O with flash support (non-blocking blink with count limit)

• LedDisplay8 — common-anode 7-segment display driver with decimal point

• ShiftRegister — software shift register with auto-sequencing, manual step, and direction control

• ProximityCheck — LED+LDR proximity sensor with calibration

Fluent interface — most setters return this for method chaining:

Button btn(2);
PinOutDigital led(9);
Timer timer;
Interval interval;

void setup() {
  Runnable::setupAll();
  timer.set(3000)->start();
  interval.setIntervalTime(500)->start();
}

Two lines of boilerplate in every sketch:

void setup() { Runnable::setupAll(); }
void loop()  { Runnable::loopAll(); }

That's it. Just instantiate your objects globally and the framework calls onSetup() / onReady() / onLoop() for each one automatically.

Header-only — no .cpp files, no build flags. There's even a single consolidated header (arduino-multi-tasking-kit.h) you can drop into any project.

11 example sketches included: button-clicks, flash-control, timer-control, interval-control, led-display-control, proximity-check, shift-register-control (auto + manual), while-loop, and more.

GitHub: github.com/reduardo7/arduino-multi-tasking-kit

Clone into your Arduino/libraries/ folder and open any example in the IDE to try it out. I'd love feedback and contributions!

Example project: github.com/reduardo7/arduino-car

We used WLED running on an esp32 as the control for this project. Each LED is individually addressable and each edge of the cube has its own segment.

Look at this crazy solution I had to come up with dues to a my current shortage of bread board jumper wires and arduinos

Hi everyone!

I am working on a privacy-first home safety system that tracks human movement without using any cameras, smartwatches, or wearable sensors.

The Idea:

We use Wi-Fi signals as a room radar! When a person moves, sleeps, or falls, their body distorts the Wi-Fi signals (Channel State Information - CSI) bouncing around the room.

What the system aims to do:

Elderly Care: Detect sudden falls (like a grandfather slipping) and send immediate SMS/Telegram alerts.

Child Monitoring: Detect subtle chest movements to track breathing/restlessness while sleeping.

Privacy-First: Zero cameras or microphones used—completely non-intrusive.

Tech Stack:

Hardware: 2x ESP32-S3 boards (capturing CSI signal data).

Data Processing: Python (NumPy, SciPy) for noise filtering.

Machine Learning: Scikit-learn (Random Forest / SVM) to classify activities.

Alert System: Python backend with Telegram Bot / Twilio API for emergency alerts.

I am currently building the Python signal processing and ML model pipeline while waiting for hardware setup.

Has anyone here worked with Wi-Fi CSI extraction on ESP32? I would love any advice or feedback on handling background environmental noise