Segments light up as a person's step goal is achieved.

Slither: A Visual Pedometer That Sheds Light

January 7, 2022 by Kristina Panos No comments

Have you already broken that New Year’s resolution to get more exercise? Yeah, us too. Maybe the problem is simply that we didn’t gamify the goal. A simple visual aid that shows your progress can help make a goal more achievable and easier to stick to, day after January day. That’s the idea behind [skhackett]’s Slither, the visual pedometer.

Although Slither uses the Fit Bit app, no actual Fit Bit is required — great news for those of us who don’t like to wear accessories. But you will have to carry your phone everywhere if you want your steps to count. By tracking the steps taken each day, the sum of Slither’s segments signifies a weekly total goal of 50,000 steps.

Around back is a Feather Huzzah that receives step data from the phone and drives a strand of side-lit LED strips. There’s a Hall effect sensor in the tail, and Slither is powered on and off with a small, separate piece of wood and acrylic with a magnet embedded inside. Isn’t that a classy way to switch a snake?

We really like the look of the plywood here, though [skhackett] recommends using MDF instead because they experienced a fair amount of chipping. If you just want to watch the snake light up, it shouldn’t be too hard to cheat the pedometer.

Tiny LED Matrix Panels Tile Together Perfectly

January 6, 2022 by Dan Maloney 15 Comments

There’s a lot to admire about LED matrix projects, which more often than not end up looking really cool. But most of them rely on RGB matrix panels sourced from the surplus market, and while there’s nothing wrong with that, building your own tiny, tileable LED matrix panels makes these builds just a little bit cooler.

There’s a lot to admire about these matrix panels, not least of which is the seamless way they tile together. But to get to that point, [sjm4306] had a lot of prep work to do. He started with a much simpler 5×7 array, using the popular WS2812 RGB LEDs on a custom PCB. With a little practice under his belt, it was time to move to the much smaller SK6805 LEDs, which were laid out in an 8×8 matrix. The board layout is about as compact as it can be; [sjm4306] reports that it pushed the PCB fab to their limits, but he ended up with LEDs spaced perfectly on the board and just enough margin to keep consistent spacing in two dimensions when the boards are adjacent to each other.

Assembly of the boards was challenging, to say the least. The video below shows that the design left barely enough room for handling the LEDs with tweezers, and some fancy finagling was needed to get the boards on and off the hotplate for reflow. [sjm4306] says that he’ll be exploring JLC PCB’s assembly service in the future, since each board took an hour for him to assemble. But they look fantastic when daisy-chained together, with no detectable gaps at the joints.

With matrices like these, the possibilities are endless. We’ve even got a whole list of LED matrix projects over on Hackaday.io for you to check out.

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Detail of an LED display made using ping-pong balls

Modular Design Enables Huge Ping-Pong Ball LED Displays

January 4, 2022 by Robin Kearey 22 Comments

Ping-pong balls have many uses: apart from playing table tennis, they have been used for countless art projects, science experiments, and even to raise ships from the bottom of the ocean. As it turns out, they also come in handy as diffusers for LED pixels, allowing the construction of large-size displays without requiring large individual LEDs.

[david] designed an LED ping-pong ball display using 3D printed components, which allows for the construction of arbitrarily-large LED displays thanks to a strictly modular design. The basic unit is a small piece that holds a single LED module and has a cup-like structure for attaching a standard table tennis ball. Twenty-five of these basic units combine together into a panel that also contains wiring ducts. Finally, any number of these panels can be combined into a display, thanks to clips that give the structure rigidity in the out-of-plane direction.

A 3D-printed frame for making an LED display — A single panel holds 25 LEDs and comes with cable ducts. On the right is a clip for connecting multiple frames together.

Of course, simply mounting LED modules is not enough to create a display: the LEDs also need to be connected to power and data lines. [david] didn’t relish the thought of having to cut and strip 1,800 pieces of wire, and therefore devised a clever way of automating this process: he put a bunch of wires onto a piece of card stock and used a laser cutter to burn off the insulation at regular intervals. Then it was simply a matter of soldering these wires onto the LEDs and snipping off pieces along the data bus.

The finished panel is driven by a combination of a Teensy 3.2 to generate the data signals and a Raspberry Pi to process the images. You can see the rather impressive result in the video embedded below; if this inspires you to build your own, you’ll be happy to hear that the STL files and all code are available on [david]’s project page.

Massive LED displays are always fun to watch, and although this is not the first one to use ping-pong balls as diffusers, its modularity and open-source design makes this one perhaps the easiest to replicate. Assuming you have a good supplier of ping-pong balls, of course.

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Need A Small, Cheap Ammeter? Blinkenlights To The Rescue!

January 3, 2022 by Ryan Flowers 3 Comments

You know how it is. You’ve got that new project running, and while it doesn’t consume much power, it also doesn’t give much indication of whether it’s functioning or just sitting there with a dead battery. What you need is an ammeter to check power consumption, even from across the room. And it just so happens that [Manuka] has Just The Circuit You Need, complete with a demonstration in the video after the break!

Oh sure, you could grab a cheap ammeter at your favorite tool import store or site, but those are bulky and take batteries. You could put in an LED that gets dimmer as voltage drops. But wait- is that the sun shining on it? or is it on? Or has something gone awry and it’s consuming too much power?

What [Manuka] gives us is a circuit that is designed to be built into your project or project’s power supply. Using only an ultra-bright white LED, red blinking LED, PNP transistor, and a diode, the circuit gives a strong visual indication of current consumption by blinking brighter and more frequently as current increases. With a bit of calibration, accurate measurements can be obtained. All of this is made possible by using the Flashing LED as a driver for the ultra-bright LED, which is a pretty slick hack!

Flashing LEDs have a great number of uses, like protecting your family from lions. Yes, really. Got a cool tip for flashing LEDs, blinkenlights, 555’s, or any odd thing that strikes your hackers fancy? Let the tip line know!

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NeoPixel Punk Console Drives WS2812s Using 555 Timers

January 1, 2022 by Robin Kearey 2 Comments

NeoPixels, a type of LED strip with individually addressable pixels, are a firm favorite among creators of intricate light effects. They are popular for their versatility and the ease with which you can daisy-chain them. Although the protocol to drive these little LEDs can be rather tricky to implement due to tight signal timing constraints.

However, [Adrian Studer] proved that driving WS2812-based LED strips like the NeoPixel series doesn’t necessarily require hand-optimized assembly code. In fact, it doesn’t require any code at all. He built the NeoPixel Punk Console, a device that creates a light show without even using a microcontroller. Just a handful of 555 timers and some 74HC series logic work together to produce pulses with approximately correct timings.

Operating the device is as easy as tweaking a few potentiometers, just like its namesake the Atari Punk Console. It’s quite a random process though, and it might be impossible to re-create a pattern that you liked. Also, the LEDs mostly light up in primary colors at full power, though [Adrian] plans to make an improved version that drives the red, green, and blue subpixels separately. But the fact that all of this is implemented by just a bunch of 555 timers makes it a rather impressive hack by any standard.

We’ve seen more than a few ways of driving NeoPixels or similar WS2812-based LED strips, though all of them use a microprocessor of some sort; you can fire up a classic 6502, use SPI and DMA on a PIC32, or just plug in a single ARM Cortex M0+.

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Enter The Matrix With This Custom PC Side Panel

December 28, 2021 by Tom Nardi 17 Comments

With a new Matrix movie out now, it’s hardly a surprise that we’re starting to see more and more projects centered around the franchise’s iconic “Digital Rain” effect. A few particularly unique examples have floated to the top of this virtual tsunami of green-tinted sushi recipes, such as this very slick RGB LED PC side panel built by [Will Donaldson].

In place of the normal clear window in his PC case, [Will] has mounted a black acrylic sheet that has had all of the “code” characters laser-cut from it. Behind that is an array of WS2812B LED strips, nestled into vertically aligned channels that keep the light from bleeding out horizontally. A sheet of frosted plastic is sandwiched between the two, which helps diffuse the light so the individual LEDs aren’t as visible.

All of the LEDs are connected to a NodeMCU ESP8266 by way of a 74AHCT125 level-shifter, though [Will] notes you could certainly use a different microcontroller with some tweaks to the code. As it stands, the user selects from various lighting patterns using two potentiometers and a button that have been mounted next to the panel. But if you were so inclined, it certainly wouldn’t take much to adapt the firmware so that the lighting effects could be triggered from the PC.

The sticklers will note that this means the characters can’t actually change or move, but as you can see in the video below, it still looks quite impressive when the LEDs get going behind them. If you’re looking to recreate the look on a considerably smaller scale, check out this Arduino library that can make it rain on a TFT display with just a few lines of code.

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Turing Ring Is Compact

December 28, 2021 by Al Williams 2 Comments

One of the problems with a classic Turing machine is the tape must be infinitely long. [Mark’s] Turing Ring still doesn’t have an infinite tape, but it does make it circular to save space. That along with a very clever and capable UI makes this one of the most usable Turing machines we’ve seen. You can see a demo in the video below.

The device uses an Arduino Nano, a Neopixel ring, an encoder, and a laser-cut enclosure that looks great. The minimal UI has several modes and the video below takes you through all of them.

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