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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Tic Tac Arduintoe Moves The Game To 4×4

May 26, 2020 by Kristina Panos 5 Comments

We know you’re out there spending a lot more time with your loved ones, and appreciate that you may be running out of ways to keep everyone entertained. [Mukesh] dropped us a tip because he has the antidote to boredom — a new twist on that old chestnut, Tic Tac Toe.

Instead of the usual 3×3 configuration, [Mukesh] made the grid 4×4 so the game would be more engaging. Game play is otherwise the same — this Tic Tac Toe still results in a lot of draws, but they take longer and you can’t see them coming a mile away. What’s even more engaging is that you get to push clicky buttons that light up, and don’t have to draw a grid before every game.

Under the hood is an Arduino Uno that controls 16 push buttons and their corresponding RGB LEDs. Whoever goes first is blue, and player two gets pink. If you win, your color floods the board for a brief victory animation. If the game is a tie, the board turns red. We really like the printed two-piece buttons that house the LEDs and actuate the push buttons while keeping the two separate. Toe your way past the break to check out the build video.

Intrigued by the 4×4 version, but need a build that takes more time? Try building your TTT in TTL.

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Nightmare Fuel Telepresence ‘Bot May Become Your Last Friend

May 9, 2020 by Kristina Panos 15 Comments

After this pandemic thing is all said and done, historians will look back on this period from many different perspectives. The one we’re most interested in of course will concern the creativity that flourished in the petri dish of anxiety, stress, and boredom that have come as unwanted side dishes to stay-at-home orders.

[Hunter Irving] and his brother were really missing their friends, so they held a very exclusive hackathon and built a terrifying telepresence robot that looks like a mash-up of Wilson from Castaway and that swirly-cheeked tricycle-riding thing from the Saw movies. Oh, and to make things even worse, it’s made of glow-in-the-dark PLA.

Now when they video chat with friends, TELEBOT is there to make it feel as though that person is in the room with them. The Arduino Uno behind its servo-manipulated vintage doll eyes uses the friend’s voice input to control the wind-up teeth based on their volume levels. As you might imagine, their friends had some uncanny valley issues with TELEBOT, so they printed a set of tiny hats that actually do kind of make it all better. Check out the build/demo video after the break if you think you can handle it.

Not creepy enough for you? Try building your own eyes from the ground up.

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A Flag-Waving Hat For All Occasions

April 28, 2020 by Kristina Panos 5 Comments

When [Taste the Code] saw that his YouTube channel was approaching 1,000 subscribers, it was time to do something special. But celebration is no reason to be wasteful. This flag-waving celebratory hat has endless possibilities for the future.

The build is simple, which is just right for these strange times of scarcity. An Arduino Uno hot-glued to the back of the hat is directly driving a pair of 9g servos on the front. [Taste the Code] made the flags by sticking two stickers back to back with a bamboo skewer in between. The code is flavored such that the flags will wave in one of three randomly-chosen patterns — swing around, swing in reverse, and wild gesticulations.

After the novelty of the whole 1k subs thing wears off, [Taste the Code] can change the flags over to Jolly Rogers to help with social distancing. And someday in the future when things are really looking up, they can be changed over to SARS-CoV-2 victory flags, or fly the colors of a local sports team. We think it would be way cool to program some kind of real semaphore message into the flags, though the mobility might be too limited for that. Check out the build video after the break, which happens picture-in-picture as [Taste the Code] dishes out a channel retrospective and lays out a course for the future.

Even though YouTube messed with subscriber counts, we think it’s still worth making a cool counter. Here’s one with a Tetris twist.

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Simon Says, But With Servos

April 7, 2020 by Kristina Panos 12 Comments

How much easier would life be if you could just grab hold of whatever mechanism you wanted to manipulate, move it like you want, and then have it imitate your movements exactly? What if you could give a servo MIDI-like commands that tell it to move to a certain location for a specific duration? Wonder no more, because [peterbiglab] has big-brained the idea into fruition.

With just one wire, an Arduino, and some really neat code, [peter] can get this servo to do whatever he wants. First he tells the Arduino the desired duration in frames per second. Then he grabs the horn and moves it around however he wants — it can even handle different speeds. The servo records and then mimics the movements just as they were made.

The whole operation is way simpler than you might think. As [peterbiglab] demonstrates in the video after the break, the servo knows its position thanks to an internal potentiometer on the motor’s rotor. If you locate the pot output pin on the control board and run a wire from there into an Arduino, you can use that information to calibrate and control the servo’s position pretty easily. There are a ton of possibilities for this kind of control. What would you do with it? Let us know in the comments.

If you want to try this with a bunch of servos at once, might as well build yourself a little testing console.

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