Seven-Segment Shelves Do Double Duty

March 18, 2020 by Kristina Panos 13 Comments

[Lewis] of [DIY Machines] was always on the lookout for that perfect something to hang above the couch. After spending a lot of time fruitlessly searching, he designed and built this awesome shelving unit with recessed lighting that doubles as a huge 7-segment clock.

The clock part works as you probably expect — an Elegoo Nano fetches the time from a real-time clock module and displays it on the WS2812B LED strips arranged in 7-segment formations. There’s a photocell module to detect the ambient light level in the room, so the display is never brighter than it needs to be.

Don’t have a 3D printer yet? Then you may need to pass on this one. Aside from the wood back plane and the electronics, the rest of this build is done with printed plastic, starting with 31 carefully-designed supports for the shelves. There are also the LED strip holders, and the sleeve pieces that hide all the wires and give this project its beautifully finished look.

You may have noticed that the far left digit isn’t a full seven segments. If you’re committed to 24-hour time, you’d have to adjust everything to allow for that, but you’d end up with two more shelves. Given the fantastic build video after the break, it probably wouldn’t take too long to figure all that out.

We like big clocks and we cannot lie. If you have room for it, build something like this blinkenlit beauty.

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Pump Up The (Windows) Volume With Physical Sliders

March 5, 2020 by Kristina Panos 20 Comments

For as long as we can remember, Windows has provided a mixer that breaks out the volume level of every applicable application into its own slider-controlled lane. But navigating to these controls is non-trivial, especially if you’re in a hurry to silence someone on team speak. You have to stop what you’re doing, click the speaker, go into the mixer, and then go find the appropriate slider. Windows won’t respect resizes between mixer visits, so you’ll almost always have some horizontal scrolling to do.

So why on Earth would you put yourself through all of this when you could be pushing physical sliders on the fly like a DJ? A slider is just a potentiometer in a straight line, after all.

These are wired up to an Arduino Nano, which sends the serial data to a Python script on the PC that changes the volume values accordingly for whatever five programs are in the config file. Thanks to a little bit of Visual Basic, the Python script can run in the background.

[Aithorn]’s got everything you need to replicate this, so slide on over and grab the STL files and code. If you get to point where these sliders are too small, just build some bigger ones.

Stop ‘n Go DUPLO

March 3, 2020 by Kristina Panos 8 Comments

[beshur]’s 2-year-old is obsessed with transportation, so he lifted a few DUPLO blocks from the bin and made this toy traffic light as a birthday present. Hey, might as well get him used to the realities of traffic, right? It also makes for a good early hacker lesson: why buy something when you can make it yourself?

The traffic pattern is determined by an Arduino Nano V3 situated inside the carved-out rear block. There’s a push button on the side in case there’s a spill and the lights need to go blinking red until the issue is dealt with. Instead of trying to solder everything in situ and risk melting the plastic, [beshur] dead-bugged the LEDs and resistors to the Nano with a helping hands and then worked everything into the case. The 5mm LEDs fit perfectly into the drilled-out posts of a second block and produce a nice, soft glow. Proceed with caution and check it out after the break.

Of course, plastic building blocks can do real work, too. This LEGO chocolate pantograph is pretty sweet.

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Laser Tachometer Knows How Fast You Were Spinning Back There

February 12, 2020 by Kristina Panos 25 Comments

Does your drill go as fast as the manufacturer says it will? Well, you’d need a tachometer to figure that out. They’re not that expensive to buy, but as [Elite Worm] shows, they’re not that expensive to make, either — about $10 total if you get your parts from the right places. Lucky for you, he has links to everything.

Really, the links are just the tip of the iceberg here as far as the gifts that [Elite Worm] bestows upon those who choose to undertake this project. The build video (after the break, as usual; our favor to you) is fantastic, and would be perfect for a beginner because of the entrancing speed at which he builds it. The video is straight up relaxing to watch, whether you want to build one or not.

It’s a fairly simple circuit — just push the momentary switch, and the laser diode and sensor pair count the revolutions over one second. The Arduino Nano multiplies this number by 60 and displays the RPM on the OLED screen. What we absolutely love about this build is the care that taken in designing the case. There’s a designated spot for each component, and the ones without their own special holder are kept in place with printed crossbar pieces. [Elite Worm] says this has a higher refresh rate than his store-bought tacho, and we say it looks way cooler, too.

Still don’t want to make one yourself? Well, okay. Before you buy one, try using your phone to calculate RPM.

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How To Hack A Portable Bluetooth Speaker By Skipping The Bluetooth

February 4, 2020 by Roger Cheng 54 Comments

Portable Bluetooth speakers have joined the club of ubiquitous personal electronics. What was once an expensive luxury is now widely accessible thanks to a prolific landscape of manufacturers mass producing speakers to fit every taste and budget. Some have even become branded promotional giveaway items. As a consequence, nowadays it’s not unusual to have a small collection of them, a fertile field for hacking.

But many surplus speakers are put on a shelf for “do something with it later” only to collect dust. Our main obstacle is a side effect of market diversity: with so many different speakers, a hack posted for one speaker wouldn’t apply to another. Some speakers are amenable to custom firmware, but only a small minority have attracted a software development community. It doesn’t help that most Bluetooth audio modules are opaque, their development toolchains difficult to obtain.

So what if we just take advantage of the best parts of these speakers: great audio fidelity, portability, and the polished look of a consumer good, to serves as the host for our own audio-based hacks. Let’s throw the Bluetooth overboard but embrace all those other things. Now hacking these boxes just requires a change of mindset and a little detective work. I’ll show you how to drop an Arduino into a cheap speaker as the blueprint for your own audio adventures.

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Feel The Force With A Pocket Magnetometer

January 24, 2020 by Kristina Panos 12 Comments

With the rise of affordable 3D printers, we just don’t see the projects in Tic Tac boxes that we used to. That’s kind of a shame. Not only are you upcycling existing plastic when you use one, they’re decently sized component vessels for pocket builds such as [rgco]’s portable magnetometer, especially if you can get the 100-count box. Best of all, they’re see-through!

Sure, you could get a magnetometer app for your phone to test out the strength of your Buckyballs, but this is more fun, and you can use it in more places. This build doesn’t take much — an Arduino Nano reads from a Hall effect sensor and outputs the magnetic flux density in militeslas (mT) on an OLED. Fortifying the sensor by mounting it inside the body of an old (also see-through!) ballpoint pen body is a nice touch.

In order to calibrate it, [rgco] made a solenoid by wrapping a length of PVC with magnet wire. The code for this very portable and low-cost magnetometer measures the magnetic field 2000 times in under three-tenths of a second, and outputs both the mean and the standard deviation of these measurements.

Magnetometers can ID all kinds of things from submarines to Suburbans. Here’s an ESP8266 magnetometer that opens a driveway gate when it detects the car.

Sleek, Sophisticated Skittle Sorter

December 16, 2019 by Kristina Panos 5 Comments

Sorting candy by color is a classic problem that has its roots in the contract riders of rock stars who were just trying to make sure that more important contractual obligations were not being overlooked by concert venues. Through the years, candy sorting has become a classic problem for hobbyists to solve in various ways. After a false start a few years back, [little french kev] was compelled to dust off those plans and make the most compact sorter possible.

This minimalist beauty uses an Arduino Nano and RGB sensor to assess the color. At the top, a small servo rotates an arm inside the hopper that both shakes the Skittles and sets them up single file before the sensor. Another small servo spins the tube rack around to catch the rainbow. There’s an RGB LED in the base that bathes the tube from below in light that matches the Skittles. Check out the series of gifs on [little french kev]’s personal project site that show how each part works, and then watch the build video after the break.

Did you know you can roll your own color sensor from an RGB LED and a photocell? If you don’t think candy is so dandy, you could always color-sort your LEGO.

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