Finding a Lost Tooth With Science!

Sometimes the hack is a masterwork of circuit design, crafting, 3D printing and programming. Other times, the hack is knowing which tool is right for the job, even when the job isn’t your regular, run-of-the-mill, job. [John]’s son lost his tooth on their gravel driveway, so [John] set out to find it.

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White socks fluoresce under UV

When [John] set out to help his son and find the tooth, he needed a plan of attack – there was a large area to cover and, when [John] looked over the expanse of gravel the terms “needle” and “haystack” came to mind. Just scanning the ground wasn’t going to work, he needed a way to differentiate the tooth from the background. Luckily, he had a UV flashlight handy and, after testing it on his own teeth, realized that his son’s tooth would fluoresce under UV light and the gravel wouldn’t.

Off [John] went at night to find the tooth with his flashlight. He soon realized that many things fluoresce under UV light – bits of plastic, quartz crystal in the rocks, his socks. [John] eventually found the tooth, and his son is happier now. No soldering was involved, no development on breadboards, no high-voltage, but this is one of those hacks that is more about problem solving than throwing microcontrollers at a situation. In the end, though, everyone’s happy, and that’s what counts.

Jenkins Lights the Christmas Tree

Jenkins is open-source automation software that tries to automate parts of the software development process. When you submit code, for example, Jenkins will grab it, build the project with it and run any tests on it. If you have a large number of people submitting new code or data, Jenkins will wait and grab a bunch of the submissions to build. Depending on the size of the project, this can take a while, and if there’s a problem, you need to know quickly so that people aren’t waiting on a broken build. Email’s fine for this, but [dkt01] saw one of the desktop LED Christmas tree projects on Hackaday, and integrated it into his Jenkins system.

Like the other projects, WS2812b LED rings are used as the tree, and an Arduino Pro Mini runs the show, with an Ethernet LAN Module to communicate with the Python script that monitors the Jenkins build job. The Python script sends commands to the Arduino, which in turn lights up the LEDs. They light up green on a successful build and red if something fails, but during the build process, the LEDs show the current state of the build, tracking Jenkins’ progress as it builds.

Our previous Jenkins post used a big, red LED light that would light up if the build failed. [dkt01]’s build lets you know if the build is successful or has failed, but the build progress is a great addition.

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Ceiling Tiles Give it Up for Christmas LED Ornaments

The great thing about holidays is that they always seem to require some shiny things. The modern version of shiny things seems to be LEDs and advances in technology being what they are, we now have amazing programmable LEDs. And programmable LEDs mean animated shiny things! Years ago, [wpqrek] made an LED ornament using discrete components. This year he revisited his ornament and decided to make a new, animated, RGB ornament.

[Wpqrek]’s build is based around five WS2812b strips connected to an Arduino Pro Mini. The ornament itself is a thick styrofoam ceiling tile cut into a star shape with a red-painted wooden frame. Decorated with baubles and stars, the LED strips start in the center and end up at each point in the star. With each strip connected in parallel to the Pro Mini, [wpqrek] used the Arduino Light Animation library to handle the animations.

[Wpqrek] says the result is too big for his tree, so he uses it as a stand-alone ornament. Perhaps using lighter materials would help — or getting a bigger tree! Check out the Arduino lighting controller or the Trompe-l’oeil Menorah for more holiday hacks.

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These Ornaments Measure Christmas Cheer

The ornament projects we post around here tend to be simple, stand-alone projects. We are, however, well into the era of the Internet of Things (like it or not) and holiday ornaments need not be single, unconnected blinking objects. For Christmas this year, [Sean Hodgins]  came up with some connected DIY ornaments that respond to Christmas cheer.

[Sean Hodgins] had some beautiful PCBs done up in festive shapes and he hand-pastes and oven-solders the SMD components on both sides. Each one is battery powered and controlled by an ESP8266. LEDs and a button on the front of each ornament comprise the user interface. When the button is pressed, data is sent to a Phant server and a “Christmas Cheer” counter is incremented. Other ornaments, so long as they can connect to the Phant server, will periodically check the counter. If the Christmas Cheer has increased, the ornaments will play a tune and flash some lights.

The ornaments are open-source — [Sean Hodgins] posted the code and PCB designs on GitHub. They look great, and would be a good way to let people know you’re thinking of them over the holidays. Check out this light-up menorah or these lighted acrylic ornaments for more holiday fun!

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Portable Apple II On An AVR

The Apple II was one of the first home computers. Designed by Steve “Woz” Wozniak, it used the MOS technologies 6502 processor, an 8-bit processor running at about 1 MHz. [Maxstaunch] wrote his bachelor thesis about emulating the 6502 in software on an AVR1284 and came up with a handheld prototype Apple II with screen and keyboard.

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Prototype on veroboard

Originally, [maxstrauch] wanted to build an NES, which uses the same 6502 processor, but he calculated the NES’s Picture Processing Unit would be too complicated for the AVR, so he started on emulating the Apple II instead. It’s not quite there – it can only reference 12K of memory instead of the 64K on the original, so hi-res graphic mode, and therefore, many games, won’t work, but lo-res mode works as well as BASIC (both Integer BASIC and Applesoft BASIC.)

[Maxstrauch] details the 6502 in his thesis and, in a separate document, he gives an overview of the project. A third document has the schematic he used to build his emulator. His thesis goes into great detail about the 6502 and how he maps it to the AVR microcontroller. The build itself is pretty impressive, too. Done on veroboard, the build has a display, keyboard and a small speaker as well as a micro SD card for reading and storing data. For more 6502 projects, check out the Dis-Integrated 6502 and also, this guide to building a homebrew 6502.

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Another Desktop LED Xmas Tree!

We love it when someone takes inspiration from one of our posts and comes up with their own twist on it. [Matthew] liked one builds he saw on Hackaday so much, he built his own LED desktop Xmas tree!

[Matthew] was inspired by [designer2k2]’s DIY desktop Xmas tree that was posted in October. To get started, he found a set of concentric WS2812 rings over on Ali Express. The five rings total 93 LEDs, plus a single WS2812 for the top of the tree. He also got a laser cut tree model from Thingiverse and had it cut, combining the LED rings with the tree in the final product

The whole thing running on a Digispark USB Development Board from DigiStump, the same as the original project. There aren’t many details in the video, but [Matthew] has put links to where he got the rings and the tree, the laser cutting service, a link to the DigiStump website as well as a link to [designer2k2]’s original tree project. There’s no source code yet, but [Matthew] says a link to it is coming along with some more pictures.

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Speed-Test Your Toys with Die-Cast Drag Strip

I’m sure many of us remember building toy car race tracks as kids, racing the cars, and then arguing over which car came in first and who cheated because they let go of their car too soon. Ah, good times. [Phil] wanted to create a drag strip race track for his son to introduce him to die-cast cars. The only commercial drag strip [Phil] could find didn’t have an electronic start gate or a timer, so he created his own with the help of an Arduino, a servo, and some light dependent resistors.

The Arduino controls everything, the button input, the lightrace2 sensor input, and the servo. A button press tells the Arduino to start the race by pulling the start gate down and starting the timer. When the light sensor is covered, the timer for that lane stops. The time is shown for each lane using a different colored 4-digit 7-segment LED.

There were a couple of problems that had to be solved. The servo launching the cars was pulling too much power when activated so that the IR LEDs used at the finish line would dim enough to trigger before the race had even begun! [Phil]’s article goes over these issues and his design ideas as he built the track.

It’s a simple build that should provide hours of fun for [Phil]’s son and his friends over the years and will hopefully put to rest any arguments over who won. There are lots of photos in [Phil]’s article, as well as several videos showing off how things work and at the end of the article, he includes the code he used to control everything. This would be a great surprise for any nieces and nephews coming to visit over the holidays — you might want to wait for final assembly and include them in the fun!

If you like these kind of projects, we’ve seen a similar Hot Wheels timing system, and a different kind of race track based on a turntable system.

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