Reel In The Years With A Cassette Player Synth

October 1, 2020 by Kristina Panos 9 Comments

Variable-speed playback cassette players were already the cool kids on the block. How else are you going to have any fun with magnetic tape without ripping out the tape head and running it manually over those silky brown strips? Sure, you can change the playback speed on most players as long as you can get to the trim pot. But true variable-speed players make better synths, because it’s so much easier to change the speed. You can make music from anything you can record on tape, including monotony.

[schollz] made a tape synth with not much more than a variable-speed playback cassette player, an Arduino, a DAC, and a couple of wires to hook it all up. Here’s how it works: [schollz] records a long, single note on a tape, then uses that recording to play different notes by altering the playback speed with voltages from a MIDI synth.

To go from synth to synth, [schollz] stood up a server that translates MIDI voltages to serial and sends them to the Arduino. Then the DAC converts them to analog signals for the tape player. All the code is available on the project site, and [schollz] will even show you where to add Vin and and a line in to the tape player. Check out the demo after the break.

There’s more than one way to hack a cassette player. You can also force them to play full-motion, color video.

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Greeking Out With Arduinos

September 18, 2020 by Brian McEvoy 4 Comments

Learning a new language is hard work, but they say that the best way to learn something is to teach it. [Angeliki Beyko] is learning Greek, and what better way to teach than to build a vocabulary flash-card game from Arduinos, color screens, 1602 text screens, and arcade buttons? After the break, we have a video from the creator talking about how to play, the hardware she chose, and what to expect in the next version.

Pegboard holds most of the hardware except the color screens, which are finicky when it comes to their power source. The project is like someone raided our collective junk drawers and picked out the coolest bits to make a game. Around the perimeter are over one hundred NeoPixels to display the game progress and draw people like a midway game. Once invested, you select a category on the four colored arcade buttons by looking at the adjacent LCD screens’ titles. An onboard MP3 shield reads a pseudo-random Greek word and displays it on the top-right 1602 screen in English phonetics. After that, it is multiple choice with your options displaying in full-color on four TFT monitors. A correct choice awards you a point and moves to the next word, but any excuse to mash on arcade buttons is good enough for us.

[Angeliki] does something we see more often than before, she’s covering what she learned, struggled with, would do differently, and how she wants to improve. We think this is a vital sign that the hacker community is showcasing what we already knew; hackers love to share their knowledge and improve themselves.

Typing Greek with a modern keyboard will have you reaching for an alt-code table unless you make a shortcut keyboard, and if you learn Greek, maybe you can figure out what armor they wore to battle.

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Hex Matrix Clock Is Spellbinding

July 26, 2020 by Kristina Panos 8 Comments

Just when we think we’ve seen all possible combinations of 3D printing, microcontrollers, and pretty blinkenlights coming together to form DIY clocks, [Mukesh_Sankhla] goes and builds this geometric beauty. It’s kaleidoscopic, it’s mosaic, and it sorta resembles stained glass, but is way cheaper and easier.

The crucial part of the print does two jobs — it combines a plate full of holes for a string of addressable RGB LEDs with the light-dividing walls that turn the LEDs into triangular pixels. [Mukesh] designed digits for a clock that each use ten triangles. You’d need an ESP8266 to run the clock code, or if you’d rather sit and admire the rainbow light show unabated by the passing of time, just use an Arduino Uno or something similar.

Most of the aesthetic magic here is in the printed pieces and the FastLED library. It has a bunch of really cool animations baked in that look great with this design. Check out the demo video after the break. The audio is really quiet until the very end of the video, so be warned. In our opinion, the audio isn’t necessary to follow along with the build.

The humble clock takes many lovely forms around here, including pop art.

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Robotic Cornhole Board Does The Electric Slide

July 9, 2020 by Kristina Panos 9 Comments

There’s a reason why bowling lanes have bumpers and golf games have mulligans. Whether you’re learning a new game or sport, or have known for years how to play but still stink at it, everyone can use some help chasing that win. You’ve heard of the can’t-miss dart board and no-brick basketball goal. Well, here comes the robot-assisted game for the rest of us: cornhole.

The game itself deceptively simple-looking — just underhand throw a square wrist rest into a hole near the top of a slightly angled box. You even get a point for landing anywhere on the box! Three points if you make it in the cornhole. In practice, the game not that easy, though, especially if you’ve been drinking (and drinking is encouraged). But hey, it’s safer than horseshoes or lawn darts.

[Michael Rechtin] loves the game but isn’t all that great at it, so he built a robotic version that tracks the incoming bag and moves the hole to help catch it. A web cam mounted just behind the hole takes a ton of pictures and analyzes the frames for changes.

The web cam sends the bag positions it sees along with its predictions to an Arduino, which decides how it will move a pair of motors in response. Down in the cornhole there’s a pair of drawer sliders that act as the lid’s x/y gantry.

We love how low-tech this is compared to some of the other ways it could be done, even though it occasionally messes up. That’s okay — it makes the game more interesting that way. We think you should get 2 points if it lands halfway in the hole. Aim past the break to check out the build video.

Seems like there’s a robotic-assisted piece of sporting equipment for everything these days. If cornhole ain’t your thing, how’d you like to take a couple strokes off your golf game?

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This Freezer Failure Alarm Keeps Your Spoils Unspoiled

July 8, 2020 by Kristina Panos 25 Comments

Deep freezers are a great thing to have, especially when the world gets apocalyptic. Of course, freezers are only good when they’re operating properly. And since they’re usually chillin’ out of sight and full of precious goods, keeping an eye on them is important.

When [Adam] started looking at commercial freezer alarms, he found that most of them are a joke. A bunch are battery-powered, and many people complain that they’re too quiet to do any good. And you’d best hope that the freezer fails while you’re home and awake, because they just stop sounding the alarm after a certain amount of time, probably to save battery.

If you want something done right, you have to do it yourself. [Adam]’s homemade freezer failure alarm is a cheap and open solution that ticks all the boxen. It runs on mains power and uses a 100dB piezo buzzer for ear-splitting effectiveness to alert [Adam] whenever the freezer is at 32°F/0°C or above.

If the Arduino loses sight of the DHT22 temperature sensor inside the freezer, then the alarm sounds continuously. And if [Adam] is ever curious about the temperature in the freezer, it’s right there on the 7-segment. Pretty elegant if you ask us. We’ve got the demo video thawing after the break, but you might wanna turn your sound down a lot.

You could assume that the freezer is freezing as long as it has power. In that case, just use a 555.

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Cakeday Countdown Clock Is A Sweet Little Scroller

July 8, 2020 by Kristina Panos 2 Comments

If you want strangers to give you well wishes on your birthday out in the real world, you have call attention to the occasion by wearing a pointy hat or a button that says ‘today is my birthday, gimme presents’. But on your reddit cakeday, aka the day you joined, you’re automatically singled out with the addition of a slice of 8-bit cake next to your username. The great thing about your cakeday is that you’re almost guaranteed to get some karma for once, especially if you make something cakeday related like [ScottyD]’s cakeday countdown clock. But plenty of people forget what their cakeday is and miss out on the fun.

This countdown clock works like you might expect — every day that isn’t your cakeday, a message scrolls by with the number of days remaining until your next one. When the big day comes, the message becomes TODAY IS YOUR CAKE DAY. Both messages are bookended by cute little pixelated cake slices that we would apply liberally to the day-of message if we made one of these.

This simple but fun project shouldn’t put too big of a dent in your parts box, since it’s essentially an Arduino, a real-time clock module, and a 32×8 LED matrix to display the text. We love the uni-body design of the enclosure because it creates a shelf for the Arduino and gives easy access for gluing in the display from the rear. If for some reason you don’t reddit, then make one anyway and use it to count down to your IRL birthday or something. We’ve got the build video cut and plated for you to consume after the break.

We would understand if 2020 is supplying you with enough existential crises, but if not, consider building a clock that counts down the rest of your life expectancy.

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Score Big Against Boredom With Tabletop Bowling

June 21, 2020 by Kristina Panos 18 Comments

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.

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