Giant LED Matrix Fills Blank Space In The Kitchen

October 9, 2023 by Richard Baguley 8 Comments

We’ve all got one: a blank space somewhere in our home that we don’t know what to do with. [James Miller] had one above his kitchen cabinets, so he filled it with a giant LED matrix. The result is a large but surprisingly attractive LED screen that can send messages, provide illumination, or while away the idle hours of the night playing Conway’s Game of Life.

[James] built the matrix using the usual suspect for these builds: several strings of WS2812 lights . He initially ran this from a Raspberry Pi, but realized that there was no need for such a dizzying amount of computing power, so he switched to an ESP32 instead. The frame is built from wood and foam board.

The first version he built used a fabric diffuser, but after a close encounter with a flaming steak, he switched over to commercial ceiling light diffusers cut down to size. We might have been tempted to keep going and try an “egg crate” style ceiling light panel for a the smaller pixel size, but [James] thinks he has reached the “good enough” point of this project. It’s certainly a fun build, and it looks very cool with minimal materials.

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Electronic Connect 4 Console Doesn’t Use LCD

May 28, 2023 by Al Williams 9 Comments

You might think that making your own electronic games would require some kind of LCD, but lately, [Mirko Pavleski] has been making his using inexpensive 8X8 WS2812B LED panels. This lets even a modest microcontroller easily control a 64-pixel “screen.” In this case, [Mirko] uses an Arduino Nano, 3 switches, and a buzzer along with some 3D printed components to make a good-looking game. You can see it in action in the video below.

The WS2812B panels are easy to use since the devices have a simple protocol where you only talk to the first LED. You send pulses to determine each LED’s color. The first LED changes color and then starts repeating what you send to the next LED, which, of course, does the same thing. When you pause a bit, the array decides you are done, and the next train of pulses will start back at the first LED.

It looks like the project is based on a German project from [Bernd Albrecht], but our German isn’t up to snuff, and machine translation always leaves something to be desired. Another developer added a play against the computer mode. This is a simple program and would be easy to port to the microcontroller of your choice. [Mirko]’s execution of it looks like it could be a commercial product. If you made one as a gift, we bet no one would guess you built it yourself.

Of course, you could play a real robot. You could probably repurpose this hardware for many different games, too.

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Quick And Dirty Microscope Motion Control For Focus Stacking

March 11, 2023 by Dan Maloney 4 Comments

If you’ve spent much time looking through a microscope, you know that their narrow depth of field can be a bit challenging to deal with. Most microscopes are designed to only have a very thin slice of the specimen in focus, so looking at anything above or below that plane requires a focus adjustment. It’s tedious and fussy, and that makes it a perfect target for automation.

The goal behind [ItMightBeWorse]’s microscope mods is “focus stacking,” a technique where multiple images of the same sample taken at different focal planes can be stitched together so that everything appears to be in focus. Rather than twist knobs and take pictures manually, he built a simpler Arduino-based rig to do the job for him. Focus control is through a small stepper motor connected to the fine focus knob of the scope, while the DSLR camera shutter is triggered through a simple relay board. There’s also lighting control, with an RGB LED ring light that can change both the light level on the sample as well as the tint.

The code is very simple, and the setup is quite temporary looking, but the results are pretty impressive. We could do without the extreme closeup of that tick — nasty little arachnids — but the ant at the end of the video below has some interesting details. [ItMightBeWorse] doesn’t mention how the actual stacking is being done, but this CNC-based focus stacking project mentions a few utilities that take help with the post-processing.

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The Curved Nature Of Time Clock

March 3, 2023 by Al Williams No comments

While we’re told that space-time curves, we aren’t sure that was what [andrei.erdei] was going for when he built a great-looking curved LED clock. The LEDs are courtesy of a strip of 84 WS2812 smart LEDs, the curve comes from a 3D printed part, and a Wemos D1 mini provides the brains.

Like all of our favorite clocks, this one has a unique way of displaying the time. If you find the description in the post hard to understand, the video below makes it a bit easier to wrap your head around. Note the time appears in the top left corner of the video in several cases — so you can check to see if you’re reading it correctly.

The secret sauce, of course, is the curved plastic grid that holds the LEDs. Because of the unusual shape, supports are a must and there are notes in the post about the settings used to get the best results. With 84 LEDs, the software has to be careful not to turn them to full brightness at one time, or else the clock would need a 6 amp power supply. Instead, the software limits the brightness to a little less than half of the maximum. No LED is ever white, and not all LEDs are on at once. The clock works easily, according to [andrei], with a 2 A supply. The clock has a WiFi connection where you can set things up easily.

Overall, a nice-looking project that would look at home on a science fiction movie set. We’ve seen color clocks before. If you want to economize on LEDs, we’ve seen a clock with only five!

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A montage of a "death stranding" lamp in two different color modes, purple on the left and blue on the right

Illuminate Your Benched Things With This Death Stranding Lamp

January 29, 2023 by Abe Connelly 4 Comments

[Pinkman] creates a smart RGB table lamp based off of the “Odradek device” robot arm from the video game “Death Stranding”.

[Pinkman] adds a XIAO BLE nRF52840 Sense device, with Bluetooth support, microphone and TinyML capability. The nRF52840 is used to push data to the five WS2812 strips, one for each “blade” of the lamp, and also connects to a TTP223 capacitive touch controller to add touch input detection. The TinyML portion of the nRF52840 allows for custom keyword training to turn on the lamp with voice commands ([Pinkman] uses “Bling Bling”). [Pinkman] has also provided Bluetooth control, allowing the color and pattern to be changed from a phone application.

The lamp is 3D printed with the build being based off of [Nils Kal]’s Printables files. Each of the five blades has a white 3D-printed diffusor plate to help ease out the hot spots for the LED strip. The lamp is fully adjustable in addition to having cavities, channels and access points for “invisible” wiring. [Pinkman] has also upgraded the original 3D files to allow for the three wires needed to drive the WS2812, instead of the two wires that [Nils] had allotted in the original.

[Pinkman] has all of the code, STL files and training data available for download, so be sure to check it out. Lamps are a favorite of ours and we’ve featured our fair share, including 3D printed Shoji lamps and RGB wall lamps.

Video after the break!

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Addressable LEDs From A Z80

January 19, 2023 by Jenny List 3 Comments

If you buy WS2812s under the Adafruit NeoPixel brand, you’ll receive the advice that “An 8 MHz processor” is required to drive them. “Challenge Accepted!“, says [ShielaDixon], and proceeded to first drive a set from the 7.3 MHz Z80 in an RC2014 retrocomputer, and then repeat the feat from a 3.5 MHz Sinclair ZX Spectrum.

The demos in the videos below the break are all programmed in BASIC, but she quickly reveals that they call a Z80 assembler library which does all the heavy lifting. There’s no microcontroller behind the scenes, save for some glue logic for address decoding, the Z80 is doing all the work. They’re all implemented on a pair of RC2014 extension cards, a bus that has become something of a standard for this type of retrocomputer project.

So the ubiquitous LEDs can be addressed from some surprisingly low-powered silicon, showing that while it might be long in the tooth the Z80 can still do things alongside the new kids. For those of us who had the Sinclair machines back in the day it’s particularly pleasing to see boundaries still being pushed at, as for example in when a Z80 was (almost) persuaded to have a protected mode.

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"The Great Resistor" color code illumination project

The Great Resistor Embiggens The Smallest Value

November 5, 2022 by Dave Walker 29 Comments

With surface-mount components quickly becoming the norm, even for homebrew hardware, the resistor color-code can sometimes feel a bit old-hat. However, anybody who has ever tried to identify a random through-hole resistor from a pile of assorted values will know that it’s still a handy skill to have up your sleeve. With this in mind, [j] decided to super-size the color-code with “The Great Resistor”.

Resistor color code from Wikipedia with white background — How the resistor color-code bands work

At the heart of the project is an Arduino Nano clone and a potential divider that measures the resistance of the test resistor against a known fixed value. Using the 16-bit ADC, the range of measurable values is theoretically 0 Ω to 15 MΩ, but there are some remaining issues with electrical noise that currently limit the practical range to between 100 Ω and 2 MΩ.

[j] is measuring the supply voltage to help counteract the noise, but intends to move to an oversampling/averaging method to improve the results in the next iteration.

The measured value is shown on the OLED display at the front, and in resistor color-code on an enormous symbolic resistor lit by WS2812 RGB LEDs behind.

Inside view of the great resistor showing WS2812 LEDs and baffle plates — Inside The Great Resistor, the LEDs and baffle plates make the magic work

Precision aside, the project looks very impressive and we like the way the giant resistor has been constructed. It would look great at a science show or a demonstration. We’re sure that the noise issues can be ironed out, and we’d encourage any readers with experience in this area to offer [j] some tips in the comments below. There’s a video after the break of The Great Resistor being put through its paces!

If you want to know more about the history of the resistor color code bands, then we have you covered. Alternatively, how about reading the color code directly with computer vision?

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