DIY Lap Counters for Drone Racing

Drone racing is a very exciting sport, in which there is a lot of room for hackers and makers to add that special sauce into the mix. Usually the aerial finish line requires special race-timing hardware to do the lap counting, and there are timing gate transponders available for around $40. In his project CoreIR and CoreIR-Uplink, [Michael Rickert] decided to reverse engineer the IR Protocol that goes into these beacons and made a homebrew version that mimics the original. The transponders send a 7-digit number out repeatedly to a receiver at the finish line as the UAV passes by and that helps track how fast drone pilots flew around a race track. The hack involves flipping an IR LED ON and OFF with the correct timing, and [Michael Rickert] confesses that it was not as easy as he had imagined.

Using a logic analyser he was able to capture the modulated 38Khz carrier signal and extract the timing from the original beacon, but it took a number of iterations to get the code just right. The IRRemote library has a ‘sendRaw’ function which is quite helpful in these situations and was employed for the task. He experimented with a number of Arduino boards to power the project, before finally going with the Arduino Pro Mini. He has shared the code on github, along with photos of the finished hack which replaces the original circuit. The final sketches include functions to generate the 7-digit code to uniquely identify the quadcopter, which completes the hack in itself.

If that was not enough, he’s gone a step further by coding and sharing a desktop client as well, which turns this hack into a full-fledged project and should prove quite useful for drone racers on a budget. The app is written in NodeJS and packaged using the electron framework, a choice that makes for a very simple way to create cross-platform desktop applications.

A build tutorial is available for you to get started, and if drone racing seems a bit tame, check out Drone Wars for a little more carnage.

Building Custom Integrated Circuits

The first integrated circuits weren’t tiny flecks of silicon mounted to metal carriers and embedded in epoxy or ceramic. The first integrated circuits, albeit a looser definition of such, were just a few transistors, resistors, and diodes mashed together in the same package. With this in mind, [Rupert] created his own custom IC. It’s an IR receiver transmitter constructed out of a transistor, resistor, and an LED.

The attentive reader should be asking, “wait, can’t you just buy an IR receiver transmitter?” Yes, yes you can. But that’s not a hack™, and would otherwise be very uninteresting.

[Rupert]’s IC is just three parts, a 2n2222 transistor, a 220Ω resistor and an IR LED. With a good bit of deadbug soldering, these three parts were melded into something that resembled, and had the same pinout of, a Vishay TSOP4838 IR receiver. The epoxy used to encapsulate this integrated circuit is a standard 2-part epoxy and laser printer toner. Once everything is mixed up into a gooey slurry, it’s dripped over the IC producing a blob of an integrated circuit. It’s functionally identical to the standard commercial version, and looks good enough for a really cool project [Rupert]’s been working on.

Thanks [foehammer] for the tip.

The Netflix and Chill Button

While the people at Netflix were busy killing weekends around the world with marathon viewings of 90s sitcoms, they also found time to release the Netflix Switch. It’s a small device with a single button that will control your TV, turn off the lights, and order a pizza. Remember, time you enjoy wasting is not wasted time.

netflixThe Netflix Switch is a relatively simple device powered by a Particle Core, an Arduino-compatible development board with on-board WiFi. Also in this box is a LiPo battery, a few LEDs, and an IR transmitter that will send the same IR signal as the Netflix button on your TV remote, should your remote have a Netflix button.

In an unprecedented break from reality, this astute corporate branding of electronics tinkering also has design files, schematics, and real instructions that come along with it. Netflix released all of the mechanical files for their switch in Solidworks format; for the low, low price of only $4000 per Solidworks license, you too can Netflix and Chill.

Although Netflix’ implementation of tapping into a DIY electronics movement that has been around for 100 years is lacking, the spirit of the build is laudable. A single button connected to the Internet is a universal tool, and whether you want to order a pizza or make a ‘do not disturb’ button for your phone, the only limitation for the Netflix and Chill button is your imagination.

Multi Input IR Remote Control Repeater

[Peter]’s folks’ cable company is terrible – such a surprise for a cable TV provider – and the digital part of their cable subscription will only work with the company’s cable boxes. The cable company only rents the boxes with no option to buy them, and [Peter]’s folks would need five of them for all the TVs in the house, even though they would only ever use two at the same time. Not wanting to waste money, [Peter] used coax splitters can take care of sending the output of one cable box to multiple TVs, but what about the remotes? For that, he developed an IR remote control multidrop extender. With a few small boards, he can run a receiver to any room in the house and send that back to a cable box, giving every TV in the house digital cable while still only renting a single cable box.

The receiver module uses the same type of IR module found in the cable box to decode the signals from the remote. With a few MOSFETs, this signal is fed over a three-position screw terminal to the transmitter module stationed right next to the cable box. This module uses a PIC12F microcontroller to take the signal input and translate it back into infrared.

[Peter]’s system can be set up as a single receiver, and single transmitter, single receiver and multiple transmitter, many receivers to multiple transmitters, or just about any configuration you could imagine. The setup does require running a few wires through the walls of the house, but even that is much easier than whipping out the checkbook every month for the cable company.

Video below.

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