Hacklet 118 – Infrared and Universal Remote Controls

The first remote control for a TV was the Zenith Space Command back in the 1950’s. Space Command used sounds at ultrasonic frequencies to control the set. It wasn’t until the 1980’s and the Viewstar cable box that infrared entered the picture. Remote controls spread like wildfire. It wasn’t long before every piece of consumer electronics had one. Coffee tables were littered with the devices. It didn’t take long for universal remotes to hit the scene. [Woz] himself worked on the CL9 Core device, back in 1987. Even in today’s world of smart TV’s and the internet of things, universal remotes are still a big item. Hackers, makers, and engineers are always trying to build a device that works better for them. This week’s Hacklet is about some of the best universal and IR remote projects on Hackaday.io!

smoteWe start with [Harikrishna] and zmote. Zmote is an open source WiFi enabled, infrared,  360° remote control. That’s a mouthful. It might be easier to say it’s an ESP8266 and some IR LEDs. An ESP-01 module connects the device to WiFi and provides the 32-bit processor which runs the show. Learning functionality comes courtesy of a TSOP1738 modulated infrared receiver. The beauty of the Zmote is in the software. REST and MQTT connectivity are available. Everything is MIT licensed, and all the code is available on Github.



Next up is [Benjamin Kenobi] with TV Remote Control, Limited. Not everyone can operate the tiny buttons on a modern remote. [Benjamin] built this device for Easton, a special kid with a disability that impairs his motor skills. The 3D printed case holds two buttons – one for power, and one to change the channel. An Arduino Nano running [Ken Shirriff’s] IR library is the brains of the operation. The IR signal timing is hard coded for simplicity. One problem [Ben] ran into was the Nano’s high current draw, even in sleep mode. Batteries wouldn’t last a week. A simple diode circuit with a reed relay keeps the Nano shut down until Easton presses a button.


openirNext we have [Nevyn] with OpenIR – Infrared Remote Control. A dead DSLR remote shutter release was all the motivation [Nevyn] needed to start work on his own universal remote control. OpenIR can be connected to (and controlled by) just about anything with a UART – a PC via an FTDI cable, a Bluetooth module, even an ESP8266. The module can be programmed by entering pulse length data through a custom Windows application. The Windows app even allows the user to view the pulses graphically, like a scope. The data is stored on an EEPROM on OpenIR’s PCB. Once programmed, the OpenIR board is ready to control the world.

onebuttonFinally, we have [facelessloser] with One button TV remote. This project may be the simplest open source remote control this side of TV-B-GONE. He wanted to build a simple remote control for his young daughter to scan between the various kids channels. A simple toggle switch turns the device on, and one button performs the rest of the magic. [Facelessloser] wanted to “move up” from an Arduino to an ATtiny85. This project became part of his ATtiny education. A custom PCB from OSH Park ties things together. A simple black project box keeps the electronics safe from tiny fingers – at least until she’s old enough to use a screwdriver.

If you want to see more IR and universal remote projects, check out our new infrared and universal remote projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Cute USART Trick Brings PWM to IR LEDs

We love little tricks like this. Suppose that you want to generate an IR remote’s signal. It’s easy, because most of the codes are known. But it can be slightly harder because most IR remotes and receivers modulate the on pulses with a square wave at roughly 38 kHz for background lighting immunity.

With a competent PWM generator on a microcontroller, you can create this carrier modulation easily enough yourself. Set the PWM frequency to 38 kHz and the duty cycle somewhere in the 33%-50% range, and you’re set. But what if you don’t have a competent PWM generator? Such was the case that prompted [AnalysIR Blog] to fake it, with USART.

Here’s the trick. You set up the serial port to communicate at ten times the desired carrier frequency, and then transmit “special” data. (The number ten comes from eight bits of data plus a start and a stop bit.) If you want a 50% duty cycle, you simply send 0b11110000, as fast as the microcontroller will allow, for a mark and nothing for a space.

There’s some extra detail with inverting the signal if, as most do, your USART idles high. But that’s really it. It’s a cute trick for when you’re desperate enough to need it. And if you’d like to brush up some more on your asynchronous serial skills, check out our guide on troubleshooting USART, and the great comments that ensued.

Using Missile Tech to See Like Predator

[Artem Litvinovich] wanted to see by heat vision like in the Predator movies. He not only succeeded but went on to see in color, medium-wave IR, short-wave IR, and ultraviolet using a very unique approach since his effort began back in 2009.

He started with a box based on the basic pinhole camera concept. In the box is a physical X-Y digitizer moving a photodiode to collect the thousands of points needed to create a picture. First all he got, due to the high signal amplification, was the 60 cycle hum that permeates our lives. A Faraday cage around the box helped but metal foil around the sensor and amplifier finally eliminated the noise. Now he had pictures in the near infrared (NIR). Continue reading “Using Missile Tech to See Like Predator”

Infrared Detector Selects Over a Wide Range

You can classify infrared light into three broad ranges: short wave, medium wave, and long wave. Traditionally, sensors concentrate on one or two bands, and each band has its own purpose. Short wave IR, for example, produces images similar to visible light images. Long wave is good for thermal imaging.

Researchers have announced a new detector that, by adjusting a bias, can detect all three bands using a simple approach that stacks different absorption layers over a semiconductor substrate. The device only requires two terminals and is very efficient, although the efficiency varies based on the band.

We’ve covered infrared sensing before. We’ve even seen DSLRs hacked into IR sensors. This new research might be a bit much to duplicate in your garage. After all, it requires tellurium doped gallium antimonide substrates and sophisticated processing equipment. However, this research will probably lead to practical devices that will find their way into projects before too long.

Cyclists Use Tiny Motors to Cheat

Blood doping is so last decade! The modern cyclist has a motor and power supply hidden inside the bike’s frame.

We were first tipped off to the subject in this article in the New York Times. A Belgian cyclocross rider, Femke Van den Driessche, was caught with a motor hidden in her bike.

While we don’t condone sports cheating, we think that hiding a motor inside a standard bike is pretty cool. But it’s even more fun to think of how to catch the cheats. The Italian and French press have fixated on the idea of using thermal cameras to detect the heat. (Skip to 7:50 in the franceTVsport clip.) We suspect it’s because their reporters recently bought Flir cameras and are trying to justify the expense.

The UCI, cycling’s regulatory body, doesn’t like thermal. They instead use magnetic pulses and listen for the characteristic ringing of a motor coil inside the frame. Other possibilities include X-ray and ultrasonic testing. What do you think? How would you detect a motor inside a bike frame or gearset?

Hackaday Reviews: Flir One Android

The Flir One thermal camera caused quite a stir when it was launched back in 2014. Both the Flir One and its prime competitor Seek Thermal represented the first “cheap” thermal cameras available to the public. At the heart of the Flir One was the Lepton module, which could be purchased directly from Flir Systems, but only in quantity. [Mike Harrison] jumped on board early, cutting into his Flir One and reverse engineering the Lepton module within, including the SPI data required to talk to it. He even managed to create the world’s smallest thermal imager using a the TFT screen from an Ipod Nano.

flircamA few things have changed since then. You can buy Lepton modules in single quantity at DigiKey now. Flir also introduced a second generation of the Flir One. This device contains an updated version of the Lepton. The new version has a resolution of 160 x 120 pixels, doubled from the original module. There are two flavors: The iOS version with a lightning port, and an Android version with a micro USB connector. I’m an Android user myself, so this review focuses on the Android edition.

The module itself is smaller than I expected. It comes with a snap-on case and a lanyard. While you’ll look a bit like a dork wearing the lanyard, it does come in handy to keep the imager from getting lost or dropped. The Flir One has an internal battery, which of course needs to be topped off before it can be used. Mine charged up in about half an hour.

Continue reading “Hackaday Reviews: Flir One Android”

Man Shoots Lamp

What do you get when you mix together all of the stuff that you can get for cheap over eBay with a bit of creativity and some PVC pipe? [Austiwawa] gets a table lamp, remote-controlled by a toy gun, that turns off and falls over when you shoot it. You’ve got to watch the video below the break.

This isn’t a technical hack. Rather it’s a creative use of a bunch of easily available parts, with a little cutting here and snipping there to make it work. For instance, [Austiwawa] took a remote control sender and receiver pair straight off the rack and soldered some wires to extend the LED and fit it inside the toy gun. A relay module controls the lamp, and plugs straight into the Arduino that’s behind everything. Plug and play.

Which is not to say the lamp lacks finesse. We especially like the screw used as an end-of-travel stop for the servo motor, and the nicely fabricated servo bracket made from two Ls. And you can’t beat the fall-over-dead effect. Or can you? Seriously, though, great project [Austiwawa]!

Continue reading “Man Shoots Lamp”