Laser Cutting Your Way To An RGB LED Table

You’ve got the RGB keyboard, maybe even the RGB mouse. But can you really call yourself master of the technicolor LED if you don’t have an RGB table to game on? We think you already know the answer. Luckily, as [ItKindaWorks] shows in his latest project, it’s easy to build your own. Assuming you’ve got a big enough laser cutter anyway…

The construction of the table is quite straightforward. Using an 80 watt laser cutter, he puts a channel into a sheet of MDF to accept RGB LED strips, a pocket to hold a Qi wireless charger, and a hole to run all the wires out through. This is then backed with a second, solid, sheet of MDF.

Next, a piece of thin wood veneer goes into the laser cutter. In the video after the break you can see its natural tendency to roll up gave [ItKindaWorks] a little bit of trouble, but when strategically weighted down, it eventually lays out flat. He then uses the laser to blast an array of tiny holes in the veneer, through which the light from the LEDs will shine when it’s been glued over the MDF. A few strips of plastic laid over the strips serve both to diffuse the light and support the top surface.

The end result is truly gorgeous and has a very futuristic feel. Assuming you’ve got the equipment, it’s also a relatively simple concept to experiment with. It’s yet another example of the unique construction techniques possible when you add a high-powered laser to your arsenal.

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Charging Pad Flips For Solar Power

Charging pads are now a common, popular way to charge small devices. They have the benefit of reducing wear on connectors and being easier to use. [bcschmi6] decided to build a solar powered charging pad, which should come in handy when out and about.

The build uses a 3 W square solar panel, hooked up to an Adafruit solar charging board. This charges a pair of 18650 lithium batteries. The batteries only put out a maximum of 4.2 V, so they’re hooked up to a boost converter to get the output a little higher, up to 5.2 V. The output of the boost converter is then hooked up to a charging pad harvested from an Anker charger, and it’s all wrapped up in a tidy 3D printed frame.

We imagine the device would be great for camping. It could be left charging in the sun during the day, before being flipped over and used as a charging pad at night. It would be easy to build a bigger version for charging several phones at once, too. If you want to build your own charging coils, that’s a thing, too. And if you’ve got your own solar project cooking up as we head into summer, be sure to let us know!

Motorized LEGO Train Gets Qi Charging In The Track

This project started, as many do, with a simple idea. [Ben Hoad] just wanted to take a static LEGO Hogwarts Express train kit and make it motorized. It was compatible with standard LEGO track pieces, so all he should have to do was figure out how to shoehorn a motor in there and be done with it. Right?

Well, you already know how things like this go. It started with adding the motor, which ended up being relatively straightforward once [Ben] used some community LEGO CAD tools to figure out which kits had the specific parts he needed to redesign the train in such a way that he’d have enough space inside for the motor without ruining the way it looked. But then the feature creep kicked in, and he found himself falling down that familiar rabbit hole.

A 3D representation of the train’s internal components.

The first problem was how to reliably power the train. It turns out the rear car was more or less empty already, so that became home for two 18650 batteries (the project details say “16850” but we believe that is merely a typo). [Ben] didn’t want to have to take the thing apart every time it ran down, so he wondered if it would be possible to add wireless charging.

A Qi coil in the bottom of the train car and one in a specially designed section of track got the power flowing, but getting them lined up proved a bit finicky. So he added a Hall effect sensor to the car and a strong magnet to the track, so the train would know when the coils were lined up and automatically pump the brakes.

So now he had a motorized train that could recharge itself, but how should he turn it on and off? Well, with an ESP8266 along for the ride, he figured it would be easy to add WiFi control. With a bit of code and the Homebridge project, he was able to get the train to appear as a smart switch to Apple’s HomeKit. That allows him to start and stop the train from his smartphone, complete with a routine that returns the train to the charging station once it’s finished making the rounds. [Ben] says the next steps are to put some sanity checks in, such as shutting the motors down if the train hasn’t passed the charging station in a few minutes; a sure sign that it’s not actually moving.

All [Ben] needs to do now is implement automatic LEGO train decoupling before the plastic Hogwarts students come back from spring break.

Make “Wireless” Earbuds Truly Wireless

[Don] bought some off-brand Bluetooth earbuds online that actually sound pretty good. But while it’s true that they don’t require wires for listening to tunes, the little storage/charging box they sleep in definitely has a micro USB port around back. Ergo, they are not truly wireless. So [Don] took it upon himself to finish what the manufacturer started. Because it’s 2019, and words have meaning.

Finally, he had a use for that Qi charger he’s had lying around since the Galaxy S5 era. [Don] pried the earbud case open with a guitar pick and found a nicely laid-out charging circuit board without any black goop.

Once he located ground and Vcc pads, it was just a matter of performing a bit of surgery on the coil’s pins so he could solder wires there instead. Miraculously, the Qi coil fit perfectly inside the bottom of the case and the plastic is thin enough that it doesn’t interfere with the charging.

Want to try it for yourself? [Don]’s done an excellent job of documenting this hack, with clear pictures of every step. Soon you’ll be able to rid yourself of all those pesky USB cables.

Of course, [Don] still has to plug the charging base into the wall. If he ever wanted to add another level of wireless, he could always retrofit the base coil into his laptop.

Dig Into The Apple Device Design Guide

Millions of people worldwide have just added new Apple gadgets to their lives thanks to the annual end of December consumerism event. Those who are also Hackaday readers are likely devising cool projects incorporating their new toys. This is a good time to remind everybody that Apple publishes information useful for such endeavors: the Accessory Design Guidelines for Apple Devices (PDF).

This comes to our attention because [Pablo] referenced it to modify an air vent magnet mount. The metal parts of a magnetic mount interferes with wireless charging. [Pablo] looked in Apple’s design guide and found exactly where he needed to cut the metal plate in order to avoid blocking the wireless charging coil of his iPhone 8 Plus. What could have been a tedious reverse-engineering project was greatly simplified by Reading The… Fine… Manual.

Apple has earned its reputation for hacker unfriendliness with nonstandard fasteners and liberal use of glue. And that’s even before we start talking about their digital barriers. But if your project doesn’t involve voiding the warranty, their design guide eliminates tedious dimension measuring so you can focus on the fun parts.

Dimensioned drawing of Apple iPad Pro

This guide is packed full of dimensioned drawings. A cursory review shows that they look pretty good and aren’t terrible at all. Button, connector, camera, and other external locations make this an indispensable tool for anyone planning to mill or print an interface for any of Apple’s hardware.

So let’s see those projects! Maybe a better M&M sorter. Perhaps a time-lapse machine. Or cure your car’s Tesla envy and put a well-integrated iPad into the dashboard.

Instrument Packed Pedal Keeps Track Of Cyclist’s Power

Exactly how much work is required to pedal a bike? There are plenty of ways to measure the power generated by a cyclist, but a lot of them such as heavily instrumented bottom brackets and crank arms, can be far too expensive for casual use. But for $30 in parts you can build this power-measuring bike pedal. and find out just how hard you’re stoking.

Of course it’s not just the parts but knowing what to do with them, and [rabbitcreek] has put a lot of thought and engineering into this power pedal. The main business of measuring the force applied to the crank falls to a pair of micro load cells connected in parallel. A Wemos, an HX711 load-cell amp, a small LiPo pack and charging module, a Qi wireless charger, a Hall sensor, a ruggedized power switch, and some Neopixels round out the BOM. Everything is carefully stuffed into very little space in a modified mountain bike pedal and potted in epoxy for all-weather use. The Hall sensor keeps tracks of the RPMs while the strain gauges measure the force applied to the pedal, and the numbers from a ride can be downloaded later.

We recall a similar effort using a crank studded with strain gauges. But this one is impressive because everything fits in a tidy package. And the diamond plate is a nice touch.

Embedding Wireless Charging Into Your Laptop

Wireless charger in chromebook

Looking for a project to do [Jason Clark] thought it might be fun to integrate a spare wireless Qi charger into his HP Chromebook 14.

He started by cracking open the Qi charger — it’s held together by adhesive and four phillips screws hiding under the feet pads — all in all, not that difficult to do. Once the plastic is off, the circuit and coil are actually quite small making it an ideal choice for hacking into various things. We’ve seen them stuffed into Nook’s, a heart, salvaged for a phone hack…

Anyway, the next step was opening up the Chromebook. The Qi charger requires 5V at 2A to work, which luckily, is the USB 3.0 spec — of which he has two ports in the Chromebook. He identified the 5V supply on the board and soldered in the wires directly —  Let there be power!

While the coil and board are fairly small, there’s not that much space underneath the Chromebook’s skin, so [Jason] lengthened the coil wires and located it separately, just below the keyboard. He closed everything up, crossed his fingers and turned the power on. Success!

It’d be cool to do something similar with an RFID reader — then you could have your laptop locked unless you have your RFID ring with you!