Smart Lamp Keeps Students On Track With Image Recognition

June 15, 2025 by 5 Comments

It’s a common enough problem: you’re hitting the books, your phone dings with a notification, and suddenly it’s three hours later. While you’ve done lots of scrolling, you didn’t do any studying. If only there were a quick, easy project that would keep an eye on you and provide a subtle nudge to get you off the phone. [Makestreme] has that project, an AI study lamp that shifts from warm white to an angry red to remind students to get back to work. See it in action in the demo video below.

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Tidy LED Matrix Displays GIFs On Demand

May 30, 2025 by 4 Comments

When it comes to LED matrixes, building one is just the first step. Then you have to decide what to display on it. [panjanek] came up with a relatively flexible answer to this question, building an RGB LED matrix that can display the GIFs of your choice.

The web interface accepts GIFs for display.

[panjanek] grabbed WS2812B addressable LEDs for this project, assembling them into a 32 x 32 matrix that fits perfectly inside an off-the-shelf Ikea picture frame. The matrix is hooked up to an ESP8266 microcontroller, which acts as the brains of the operation. The WiFi-enabled microcontroller hosts its own web interface, with which the project can be controlled. Upon opening the page, it’s possible to upload a GIF file that will be displayed as an animation on the matrix itself. It’s also possible to stream UDP packets of bitmap data to the device to send real-time animations over a network.

It’s a neat build, and one that answers any questions of what you might display on your LED matrix when you’re finished assembling it. Code is on Github if you fancy implementing the GIF features in your own work. We’ve featured some unexpected LED matrix builds of late, like this innovative device for the M.2 slot. Meanwhile, if you’re cooking up your own creative LED builds, don’t hesitate to let us know on the tipsline!

Handheld 18650 Analyzer Scopes Out Salvaged Cells

April 3, 2025 by 10 Comments

You can salvage lithium 18650 cells from all sorts of modern gadgets, from disposable vapes to cordless power tools. The tricky part, other than physically liberating them from whatever they are installed in, is figuring out if they’re worth keeping or not. Just because an 18650 cell takes a charge doesn’t necessarily mean it’s any good — it could have vastly reduced capacity, or fail under heavy load.

If you’re going to take salvaging these cells seriously, you should really invest in a charger that is capable of running some capacity tests against the cell. Or if you’re a bit more adventurous, you can build this “Battery Health Monitor” designed by [DIY GUY Chris]. Although the fact that it can only accept a single cell at a time is certainly a limitation if you’ve got a lot of batteries to go though, the fact that it’s portable and only needs a USB-C connection for power means you can take it with you on your salvaging adventures.

The key to this project is a pair of chips from Texas Instruments. The BQ27441 is a “Fuel Gauge” IC, and is able to determine an 18650’s current capacity, which can be compared to the cell’s original design capacity to come up with an estimate of its overall health. The other chip, the BQ24075, keeps an eye on all the charging parameters to make sure the cell is being topped up safely and efficiently.

With these two purpose-built chips doing a lot of the heavy lifting, it only takes a relatively simple microcontroller to tie them together and provide user feedback. In this case [DIY GUY Chris] has gone with the ATmega328P, with a pair of addressable WS2812B LED bars to show the battery’s health and charge levels. As an added bonus, if you plug the device into your computer, it will output charging statistics over the serial port.

The whole project is released under the MIT license, and everything from the STL files for the 3D printed enclosure to the MCU’s Arduino-flavored firmware is provided. If you’re looking to build one yourself, you can either follow along with the step-by-step assembly instructions, or watch the build video below. Or really treat yourself and do both — you deserve it.

If your battery salvaging operation is too large for a single-cell tester, perhaps it’s time to upgrade to this 40-slot wall mounted unit.

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Low-Resolution Fluid Simulation On An ESP32

February 28, 2025 by 2 Comments

Fluid simulations are a key tool in fields from aerospace to motorsports and even civil engineering. They can be three-dimensional and complicated and often run on supercomputer clusters bigger than your house. However, you can also do simple two-dimensional fluid simulations on very simple hardware, as [mircemk] demonstrates.

This build is almost like a simple toy that displays particles rolling around and tumbling as you turn it one way or the other. Behind the scenes, an ESP32 is running the show, simulating a group of particles responding to gravity in a fluid-like manner. The microcontroller is  hooked up with an 3-axis gyroscope and accelerometer, which it uses to track motion and influence the motion of the particles in turn. The results of the simple fluid simulation are displayed on a screen made up of a 16 x 16 matrix of WS2812B addressable RGB LEDs, which add enough color to make the build suitably mesmerizing.

There’s something compelling about turning the display and watching the particles tumble and flow, particularly when they’re all set to different colors. [mircemk] also gave the build the ability to operate in several different modes, running “sand,” “liquid” and “gas” simulations and with dynamic coloring to boot.

We’ve seen some great videos from [mircemk] before, too, like this sensitive metal detector rig. Continue reading “Low-Resolution Fluid Simulation On An ESP32” →

To Test A (Smart) LED

February 24, 2025 by 14 Comments

Adding LEDs to a project used to be enough to make it cool. But these days, you need arrays of addressable multi-color LEDs, and that typically means WS2812B or something similar. The problem is that while it was pretty easy to test garden-variety LEDs, these devices can be a bit harder to troubleshoot. [Gokux] has the answer, as you can see in the video below.

Testing these was especially important to [Gokux] because they usually swipe the modules from other modules or LED strips. The little fixture sends the correct pulses to push the LED through several colors when you hold it down to the pads.

However, what if the LED is blinking but not totally right? How can you tell? Easy, there’s a reference LED that changes colors in sync with the device under test. So, if the LEDs match, you have a winner. If not… well, it’s time to desolder another donor LED.

This is one of those projects that you probably should have thought of, but also probably didn’t. While the tester here uses a Xiao microcontroller, any processor that can drive the LEDs would be easy to use. We’d be tempted to breadboard the tester, but you’d need a way to make contact with the LED. Maybe some foil tape would do the trick. Or pogo pins.

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Home Depot Lamp Gets A Rainbow Upgrade

February 14, 2025 by 14 Comments

Home Depot has at times sold a neat spiral lamp that relies on LEDs to supply its soothing white glow. When [Craig Lindley] saw some modified versions on YouTube he decided he had to build one himself. The result is a charming rainbow lamp that really lights up a room (pardon the pun).

[Craig] first set about stripping the lamp of its white LED strips, replacing them with addressable WS2812B LEDs. No more would the lamp just output white light—any color in the RGB gamut was now on the table.

A powerful 10 amp 5 volt power supply was then installed to provide the necessary juice. A Wemos D1 Mini was pressed into service as the controller, which was also hooked up to an HC-SR04 infrared motion sensor. This provided the capacity to trigger the lamp when it detects someone moving nearby.

Alternatively, the lamp was given a time-activated mode as well. Either way, when activated, the lamp displays a range of colorful patterns on its elegant spirals, all with the aid of the popular FastLED library.

The final result is impressive—it looks almost stock, except it’s far more colorful and interesting to look at than the original. It’s also amusingly hard to display in our usual image formats because it’s so tall and narrow. In any case, we’ve seen some great lamp builds before, too. If you’re working on your own charming illuminations, don’t hesitate to drop us a line!

Interactive LED Matrix Is A Great Way To Learn About Motion Controls

January 21, 2025 by 4 Comments

It’s simple enough to wire up an LED matrix and have it display some pre-programmed routines. What can be more fun is when the LEDs are actually interactive in some regard. [Giulio Pons] achieved this with his interactive LED box, which lets you play with the pixels via motion controls.

The build runs of a Wemos D1 mini, which is a devboard based around the ESP8266 microcontroller. [Giulio] hooked this up to a matrix of WS2812B addressable LEDs in two 32×8 panels, creating a total display of 512 RGB LEDs. The LEDs are driven with the aid of an Adafruit graphics library that lets the whole display be addressed via XY coordinates. For interactivity, [Giulio] added a MPU6050 3-axis gyroscope and accelerometer to the build. Meanwhile, power is via 18650 lithium-ion cells, with the classic old 7805 regulator stepping down their output to a safe voltage. Thanks to the motion sensing abilities of the MPU6050, [Giulio] was able to code animations where the LEDs emulate glowing balls rolling around on a plane.

It’s a simple build, but one that taught [Giulio] all kinds of useful skills—from working with microcontrollers to doing the maths for motion controls. There’s a lot you can do with LED matrixes if you put your mind to it, and if you just start experimenting, you’re almost certain to learn something. Video after the break.

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