Let’s face it — eating different colored candy like M&Ms or Skittles is just a little more fun if you sort your pile by color first. The not-fun part is having to do it by hand. [Jackofalltrades_] decided to tackle this time-worn problem for engineering class because it’s awesome and it satisfies the project’s requirement for sensing, actuation, and autonomous sequencing. We’d venture to guess that it satisfies [Jackofalltrades_]’ need for chocolate, too.

Here’s how it works: one by one, M&Ms are selected, pulled into a dark chamber for color inspection, and then dispensed into the proper cubby based on the result. [Jackofalltrades_] lived up to their handle and built a color-detecting setup out of an RGB LED and light-dependent resistor. The RGB LED shines red, then, green, then blue at full brightness, and takes a voltage reading from the photocell to figure out the candy’s color. At the beginning, the machine needs one of each color to read in and store as references. Then it can sort the whole bag, comparing each M&M to the reference values and updating them with each new M&M to create a sort of rolling average.

We love the beautiful and compact design of this machine, which was built to maximize the 3D printer as one of the few available tools. The mechanical design is particularly elegant. It cleverly uses stepper-driven rotation and only needs one part to do most of the entire process of isolating each one, passing it into the darkness chamber for color inspection, and then dispensing it into the right section of the jar below. Be sure to check out the demo after the break.

Need a next-level sorter? Here’s one that locates and separates the holy grail of candy-coated chocolate — peanut M&Ms that didn’t get a peanut.

Like many of us, [Emily’s Electric Oddities] has had a lot of time for projects over the past year or so, including one that had been kicking around since late 2018. It all started at the Hackaday Superconference, when [Emily] encountered the Adafruit Hallowing board in the swag bag. Since that time, [Emily] has wanted to display the example code eyeball movement on a CRT, but didn’t really know how to go about it. Spoiler alert: it works now.

Eventually, [Emily] learned about the TV out library for Arduino and got everything working properly — the eyeball would move around with the joystick, blink when the button is pressed, and the pupil would respond visually to changes in ambient light. The only problem was that the animation moved at a lousy four frames per second. Well, until she got Hackaday’s own [Roger Cheng] involved.

[Roger] was able to streamline the code to align with [Emily]’s dreams, and then it was on to our favorite part of this build — the cabinet design. Since the TV out library is limited to black and white output without shades of gray, Emily took design cues from the late 70s/early 80s, particularly the yellow and wood of the classic PONG cabinet. We love it!

Is Your Pet Eye the worst video game ever, as [Emily] proclaims it to be? Not a chance, and we’re pretty sure that the title still rests with Desert Bus, anyway. Even though the game only lasts until the eye gets tired and goes to sleep, it’s way more fun than Your Pet Rock. Don’t miss the infomercial/explanation/demonstration video after the break. If one video is just not enough, learn more about [Emily’s] philosophy of building weird projects from the Supercon talk she presented. It’s also worth mentioning that this one fits right into the Reinvented Retro contest.

Why are eyeballs so compelling? We can’t say for sure, but boy, this eyeball web cam sure is disconcerting.

Thanks for the tip, [Jake_of_All_Trades]!

As the pandemic rages on, so does the desire to spend the idle hours tinkering. [knaylor1] spent the second UK lockdown making a sweet Theremin-inspired noise machine with a low parts count that looks like a ton of fun.

It works like this: either shine some light on the photocells, cover them up, or find some middle ground between the two. No matter what you do, you’re going to get cool sounds out of this thing.

The photocells behave like potentiometers that are set up in a voltage divider. An Arduino UNO takes readings in from the photocells, does some MIDI math, and sends the serial data to a program called Hairless MIDI, which in turn sends it to Ableton live.

[knaylor1] is using a plugin called TAL Noisemaker on top of that to produce the dulcet acid house tones that you can hear in the video after the break.

If you’ve never played with light-dependent resistors before, do yourself a favor and spend a little bit of that Christmas cash on a variety pack of these things. You don’t even need an Arduino to make noise, you can use them as the pots in an Atari Punk console or make farty square waves with a hex inverting oscillator chip like the CD40106. Our own [Elliot Williams] once devoted an entire column to making chiptunes.

If you’re planning to get into circuit sculpture one of these days, it would probably be best to start with something small and simple, instead of trying to make a crazy light-up spaceship or something with a lot of curves on the first go. A small form factor doesn’t necessarily mean it can’t also be useful. Why not start by making a small automatic night light?

The circuit itself is quite simple, especially because it uses an Arduino. You could accomplish the same thing with a 555, but that’s going to complicate the circuit sculpture part of things a bit. As long as the ambient light level coming in from the light-dependent resistor is low enough, then the two LEDs will be lit.

We love the frosted acrylic panels that [akshar1101] connected together with what looks like right angle header pins. If you wanted to expose the electronics, localize the light diffusion with a little acrylic cover that slips over the LEDs. Check it out in the demo after the break.

There’s more than one way to build a glowing cuboid night light. The Rubik’s way, for instance.

Bowling has been around since ancient Egypt and continues to entertain people of all ages, especially once they roll out the fog machine and hit the blacklights. But why pay all that money to don used shoes and drink watered-down beer? Just build a tabletop bowling alley in your spare time and you can bowl barefoot if you want.

Those glowing pins aren’t just for looks — the LEDs underneath them are part of the scoring system. Whenever a pin is knocked out of its countersunk hole, the LED underneath is exposed and shines its light on a corresponding light-dependent resistor positioned overhead. An Arduino Uno keeps track of of the frame, ball number, and score, and displays it on an LCD.

The lane is nearly six feet long, so this is more like medium-format bowling or maybe even skee-bowling. There are probably a number of things one could use for balls, but [lainealison] is using large ball bearings. Roll past the break to see it in action, but don’t go over the line!

Can’t keep your balls out of the gutter? Build a magic ball and make all wishful leaning more meaningful as you steer it down the lane with your body.

Who would have thought you could make a game out of an optical bench? [Chris Mitchell] did, and while we were skeptical at first, his laser Light Bender game has some potential. Just watch your eyes.

The premise is simple: direct the beam of a colored laser to the correct target before time runs out. [Chris] used laser-cut acrylic for his playfield, which has nine square cutouts arranged in a grid. Red, green, and blue laser pointers line the bottom of the grid, with photosensors and RGB LEDs lining the grid on the other three sides. Play starts with a random LED lighting up in one of the three colors, acting as a target. The corresponding color laser comes on, and the player has to insert mirrors or pass-through blocks in the grid to create a path to the target. The faster you hit the CdS cell, the higher your score. It’s simple, but it looks really engaging. We can imagine all sorts of upgrades, like lighting up two different targets at once, or adding a beamsplitter block to hit two targets with the same color. Filters and polarizers could add to the optical fun too.

We like builds that are just for fun, especially when they’re well-crafted and have a slight air of danger. The balloon-busting killbots project we featured recently comes to mind.