A Nifty Tool For Counting Neopixels

August 16, 2023 by Lewin Day 25 Comments

Picture it. You’ve got a big roll of NeoPixels, but you have no idea how many are actually on the tape. Or you need to count how many WS2812B LEDs are in a display to properly plan your animations. Fear not, for [Gustavo Laureano] has built the perfect tool for counting the addressable LEDs.

The tool is based on a Raspberry Pi Pico, so it’s easy to replicate at home. The LED strip is simply connected to the microcontroller via a set of jumper wires going to the 5V and GND pins, while one of the Pico’s ADC pins is then connected to the strip’s GND pin after the jumper. A further GPIO pin is used to send data to the strip.

Essentially, this uses the jumper wire as a rudimentary current shunt. The code steps through the string of LEDs, turning each one on and then off in turn, comparing the value read by the ADC pin at each state. When the Pico detects no difference in current draw between the on and off states, that suggests it’s trying to turn on an LED beyond the end of the string, and thus the count is concluded.

You don’t need to understand any of that to put this device to good use, however. You can easily whip it up on a breadboard with a Pi Pico and parts you have lying around in the shop. Video after the break.

Continue reading “A Nifty Tool For Counting Neopixels” →

Electronic Connect 4 Console Doesn’t Use LCD

May 28, 2023 by Al Williams 7 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.

Continue reading “Electronic Connect 4 Console Doesn’t Use LCD” →

A view of the inside of a car, with drivers wheel on the left and control panel in the middle, with red LED light displayed in the floor area under the drivers wheel and passenger side.

Bass Reactive LEDs For Your Car

April 25, 2023 by Abe Connelly 32 Comments

[Stephen Carey] wanted to spruce up his car with sound reactive LEDs but couldn’t quite find the right project online. Instead, he wound up assembling a custom bass reactive LED display using an ESP32.

The entirety of the build is minimal, consisting of a GY-MAX4466 electret microphone module, a KY-040 encoder for some user control and an ESP32 attached to a Neopixel strip. The only additional electronic parts are some passive resistors to limit current on the data lines and a capacitor for power line noise suppression. [Stephen] uses various enclosures from Thingiverse for the microphone, rotary encoder and ESP32 box to make sure all the modules are protected and accessible.

The magic, of course, is in the software, with the CircuitPythyon ulab library used to do the heavy lifting of creating the spectrogram and frequency filtering. [Stephen] has made the code is available on GitHub for those wanting to take a closer look.

It wasn’t very long ago that sound reactive LEDs used to be a heavy lift, requiring optimized FFT libraries or specialized components to do the spectrogram. With faster and cheaper microcontroller boards, we’re seeing many great projects, like the sensory bridge or Raspberry Pi driven LED spectrogram, that can now take spectrograms and Fourier transform calculations as basic infrastructure to build on top of them. We’re happy to see [Stephen] leverage the ESP32’s speed and various circuit Python libraries to create a very cool LED car hack.

Video after the break!

Continue reading “Bass Reactive LEDs For Your Car” →

Displaying The Time Is Elemental With This Periodic Table Clock

March 7, 2023 by Dan Maloney 8 Comments

We see a lot of clocks here at Hackaday, so many now that it’s hard to surprise us. After all, there are only so many ways to divide the day into intervals, as well as a finite supply of geeky and quirky ways to display the results, right?

That’s why this periodic table clock really caught our eye. [gocivici]’s idea is a simple one: light up three different elements with three different colors for hours, minutes, and seconds, and read off the time using the atomic number of the elements. So, if it’s 13:03:23, that would light up aluminum in blue, lithium in green, and vanadium in red. The periodic table was designed in Adobe Illustrator and UV printed on a sheet of translucent plastic by an advertising company that specializes in such things, but we’d imagine other methods could be used. The display is backed by light guides and a baseplate to hold the WS2812D addressable LEDs, and a DS1307 RTC module gives the Arduino Nano a sense of time. The 3D printed frame of the clock has buttons for setting the time and controlling the clock; the brief video below shows it going through its paces.

We really like the attention to detail [gocivici] showed here; that UV printing really gave some great results. And what’s not to like about the geekiness of this clock? Sure, it may not be as action-packed as a game of periodic table Battleship, but it would make a great conversation starter.

Continue reading “Displaying The Time Is Elemental With This Periodic Table Clock” →

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.

Continue reading “Addressable LEDs From A Z80” →

Illuminated smart curtain in front of a window, beside a Christmas tree

Smart LED Curtain Brings Sprites To Your Windows

January 14, 2023 by Dave Walker 13 Comments

Mobile interface for LED smart curtain display — A mobile interface is a nice touch

Anybody who has ever seen a video wall (and who hasn’t?) will be familiar with the idea of making large-scale illuminated images from individual coloured lights. But how many of us have gone the extra mile and fitted such a display in our own homes? [vcch] has done just that with his Deluxe Smart Curtain that can be controlled with a phone or laptop.

The display itself is made up of a series of Neopixel strips, hung in vertical lines in front of the window. There is a wide gap between each strip, lending a ghostly translucent look to the images and allowing the primary purpose of the window to remain intact.

The brains of the system are hosted on a low-cost M5stack atom ESP32 device. The data lines for the LEDs are wired in a zig-zag up and down pattern from left to right, which the driver software maps to the rectangular images. However, the 5V power is applied to the strips in parallel to avoid voltage drops along the chain.

If you’d like to build your own smart curtain, Arduino sketch files and PHP for the mobile interface are included on the project page. Be sure to check out the brief video of what the neighbors will enjoy at night after the break.

If video walls are your kind of thing, then how about this one that uses Ping Pong Balls as diffusers? Continue reading “Smart LED Curtain Brings Sprites To Your Windows” →

"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?

Continue reading “The Great Resistor Embiggens The Smallest Value” →