Magnetic Circuits Are More Attractive Than Breadboarding

Let’s face it, breadboarding can be frustrating, even for advanced electronics wizards. If you have an older board, you could be dealing with loose tie points left from large component legs, and power rails of questionable continuity. Conversely, it can be hard to jam just-made jumper wires into new boards without crumpling the copper. And no matter what the condition of the board is, once you’ve plugged in more than a few components, the circuit becomes hard to follow, much less troubleshoot when things go pear-shaped.

In the last twenty years or so, we’ve seen systems like Snap Circuits and Little Bits emerge that simplify the circuit building process by making the connections more intuitive and LEGO-like than even those 160-in-1 kits where you shove component legs between the coils of tight little springs. You will pay handsomely for this connective convenience. But why should you? Just make your own circuit blocks with cardboard, magnets, and copper tape. It should only cost about 10¢ each, as long as you source your magnets cheaply.

[rgco] gives the lowdown on building a minimal set of 23 component and connector blocks using 100 magnets. He’s got 11 example circuits to get you started, and some example videos of more advanced circuits that got tacked up after the break.

This method of making the circuit look more like the schematic may be the best way for the visually-inclined to learn electronics. But the best way to learn electronics depends on where you’re coming from.

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Cat Diner Now Under New Management

Most of these stories start with a cat standing on someone’s chest, begging for food at some obscene hour of the morning. But not this one. Chaz the cat is diabetic, and he needs to get his insulin with breakfast. The problem is that Chaz likes to eat overnight, which ruins his breakfast appetite and his chances at properly metabolizing the insulin. [Becky] tried putting the bowl away before bed, but let’s face it — it’s more fun to solve a problem once than to solve the same problem every night.

[Becky]’s solution was to design and print a bowl holder with a lid, and to cover the bowl when the cat diner is closed using a small servo and a NodeMCU. It looks good, and it gets the job done with few components. Chaz gets his insulin, [Becky] gets peace of mind, and everybody’s happy. This isn’t going to work for all cats, because security is pretty lax. But Chaz is a senior kitty and therefore disinterested in pawing at the lid to see what happens. Claw your way past the break to see [Becky]’s build/demo video featuring plenty of cat tax coverage.

We’ve seen a lot of cat feeding apparatus around here, but few that solve a specific problem like this one. If it’s overengineering and cat metrics you want, come and get it.

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LED Flame Illuminates The Beauty Of Noise

Have you ever wrapped up a nice blinky project only to be disappointed by the predictability of the light or the color patterns? When it came to lighting this LED candle, so was [fungus amungus]. But there’s a better way, and it involves noise.

Perlin noise was created in the early 80s by Ken Perlin while he was working on the movie Tron. Frustrated by the current state of computer graphics and too limited on space to use images, he devised an algorithm for generating natural-looking textures. Basically, you generate a bunch of numbers between 0 and 1, then assign values to those numbers, such as a range of greyscale values from black (0) to white (1), or the values from the color wheel. The result is much prettier than random numbers because the neighboring values for any given number aren’t radically different. You get nice randomness with hardly any overhead.

[fungus amungus] is using the FastLED’s noise function to generate the numbers, but there’s a whole lot more going on here. As he explains in the excellent video after the break, if you want to animate these values, you just add another dimension of them. Although [fungus amungus] is using a Trinket Pro and a NeoPixel ring, we think a simplified version could be done with a Circuit Playground Express using the built-in LEDs.

If you want to do it the hard way, start by making your own NeoPixel ring.

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Circuit Sculpture Teaches Binary, Plays PONG

We sure wish we’d had a teacher like [Danko Bertović]. He built this beautiful circuit sculpture to teach his students how to count in binary and convert it to decimal and hexadecimal. If you don’t already know binary, you get to learn it on DIP switches and a dead-bugged ATMega328 in his latest Volos Projects video after the break. Lucky you!

Once the students have the hang of entering binary input on the switches, they can practice it on the four-banger calculator. This educational sculpture can also take text input and scroll it, but it takes a bit of work. You have to look up the ASCII value of each character, convert the decimal to binary, and program it in with the switches. There’s one more function on the menu — a one-player PONG game to help the students relax after a long day of flipping switches.

Funny enough, this project came to be after [Danko] came upon the DIP switch in his parts box and wasn’t quite sure what it was called. How great is it that he learned something about this part, and then used that knowledge to build this machine that uses the part to teach others? It’s surely the best fate that parts bin curiosities can hope for.

Don’t have the patience for circuit sculpture? You can make a pretty nice binary calculator with a bit of paper and a lot of compressed air.

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Team Scores Big Points With Pinball Final Project

For their final project in [Bruce Land]’s class on designing with PIC32 microcontrollers, [Sujith], [Julia] and [Andrew] wanted to do something fun. And what could be more fun than bending to the electromechanical siren song of the pinball machine?

This machine looks great, and as you can see in the demo video after the break, it plays and sounds great, too. We particularly like the boomerang obstacle and the game state-driven LED strip. The more points you score, the brighter they go. We also like that this machine combines traditional scoring methods with a few really clever ones, like the boomerang target near the top and the scoring triggers made from copper tape.

The team started by designing the heart of any pinball machine, the flippers. Though we have seen car door lock actuators used in homebrew machines, the team went with traditional solenoids to drive them. Unfortunately the solenoids caused a lot of interference, but the team got around it with filter capacitors and aluminium foil Faraday cages around the wires.

If all this pinball talk has your circuits lit up, why not try making your own machine? Continue reading “Team Scores Big Points With Pinball Final Project”

Minimalist Mate Maker Keeps You Caffeinated

Americans love their coffee. The Brits adore their tea. In South America, the number one way to get through the day is with yerba mate, a tea made from the yerba plant. It is typically shared in a social setting, with one person preparing the beverage for everyone to enjoy. Although caffeine certainly deserves a ceremony, it never needs one. Hit the streets and you’ll see people everywhere with a thermos under one arm, keeping water hot and ready to refill the cup of mate in their hand.

The Stanley vacuum thermos is quite a popular choice for drinkers on the go, but the Argentinian government recently placed new restrictions foreign imports. [Roni Bandini] decided to build a minimum viable mate machine so he always has perfectly hot water on tap.

An Arduino Nano heats the water and displays the rising temperature on an LCD screen. When the temperature is just right, the display asks for your cup. An ultrasonic sensor detects the cup and dispenses a certain amount of water determined in the sketch. Yerba leaves can be used a few times before losing their flavor, so the machine keeps track and lets him know when it’s time to replace them. You can sip on a brief demo after the break.

Let’s say you don’t have perfectly-prepared mate, and it always comes out too hot. That’s better than too cold, but still not ideal. Why not make a temperature-sensing coaster that alerts you when it has cooled to perfection?

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Tiny Tree Is A Thermometer For Christmas Fever

Tired of the usual methods for animating all those RGB LEDS for your holiday display? How about using trendiness in a non-trendy way?

[8BitsAndAByte] caved in to increasing holiday madness and bought the cutest little Christmas tree. A special tree deserves special decorations, so they packed it with NeoPixels that turn from red to green and back again one by one. Here’s where the trendiness comes in: the speed at which they change is determined by the popularity of “Christmas” as a search term.

The NeoPixels are controlled by a Raspberry Pi 3B+ that uses PyTrends to grab a value from Google Trends once an hour. The service returns a value between 0 to 100, where 100 means the search term is extremely popular, and 0 means it’s probably the dead of January. Each NeoPixel is wired to the underside of a translucent printed gift box that does a great job of diffusing the light.

You know how Christmas trees have a tendency to stick around well into the new year? This one might last even longer than usual, thanks to the bonus party mode. Press the arcade button on the box cleverly disguised as a present, and the lights change from red to green and back at warp speed while the speaker inside blasts the party anthem of your choice. Be sure to check out the demo/build video waiting for you under after the break.

How could this little tree get any more special? Well, a rotating platform couldn’t hurt.

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