Putting Pi In Infrared Doohickies

The Raspberry Pi Zero W is a tiny, cheap Linux computer with WiFi. It’s perfect for Internet of Things things such as controlling ceiling fans, window blinds, LED strips, and judgmental toasters. This leads to an obvious question: how do you attach your ceiling fan and LED strips to a Pi Zero? A lot of these things already have infrared remotes, so why not build an infrared hat for the Pi? That’s what [Leon] did, and it’s Open Hardware with documentation.

[Leon]’s Anavi Infrared Pi Hat does exactly what you think it should do. There’s an IR receiver, two IR LEDs, and UART pins for debugging. That’s all you need to control infrared doohickies over the Internet, and [Leon] wrapped it up in a nice neat package that’s the same size as a Raspberry Pi Zero. Add on some documentation and you have something we rarely see: a project meant to be used by other people.

This focus on allowing people to actually use what [Leon] created can lead to only one cynical conclusion: he’s probably selling these things somewhere. The cynic is never surprised. [Leon] has a crowdfunding campaign going, that’s over 400% funded with a month to go. That’s okay, though: all the design files are available so if you want to build your own without supporting people who build useful devices, have at it.

Own the Night with this Open Source Night Vision Monocular

If you’ve always wanted to see in the dark but haven’t been able to score those perfect Soviet-era military surplus night vision goggles, you may be in luck. Now there’s an open-source night vision monocular that you can build to keep tabs on the nighttime goings-on in your yard.

Where this project stands out is not so much the electronics — it’s really just a simple CCD camera module with the IR pass filter removed, an LCD screen to display the image, and a big fat IR LED to throw some light around. [MattGyver92] seemed to put most of his effort into designing a great case for the monocular, at the price of 25 hours of 3D printer time. The main body of the case is nicely contoured, the eyepiece has a comfortable eyecup printed in NinjaFlex, and the camera is mounted on a ball-and-socket gimbal to allow fine off-axis angle adjustments. That comes in handy to eliminate parallax errors while using the monocular for nighttime walks with both eyes open. One quibble: the faux mil-surp look is achieved with a green filter over the TFT LCD panel. We wonder if somehow eliminating the red and blue channels from the camera might not have been slightly more elegant.

Overall, though, we like the way this project came out, and we also like the way [MattGyver92] bucked the Fusion 360 trend and used SketchUp to design the case. But if walking around at night with a monocular at your face isn’t appealing, you can always try biohacking yourself to achieve night vision.

ESP8266 BASIC Sets Up a Web Remote in No Time

One of the sticking points for us with our own Internet of Things is, ironically, the Internet part. We build hardware happily, but when it comes time to code up web frontends to drive it all, the thrill is gone and the project is only half-done.

Including some simple web-based scripting functionality along with the microcontroller basics is one of the cleverest tricks up ESP8266 BASIC’s sleeves. BASIC author [mmiscool] puts it to good use in this short demo: a complete learning IR remote control that’s driven through a web interface, written in just a few lines of BASIC.

Note that everything happens inside the ESP8266 here, from hosting the web page to interpreting and then blinking back out the IR LED codes to control the remote. This is a sophisticated “hello world”, the bare minimum to get you started. The interface could look slicker and the IR remote could increase its range with more current to the LED, but that would involve adding a transistor and some resistors, doubling the parts count.

For something like $10 in parts, though, this is a fun introduction to the ESP and BASIC. Other examples are simpler, but we think that this project has an awesome/effort ratio that’s hard to beat.

Shmoocon 2017: Software Defined Radio for Terahertz Frequencies

Before Bluetooth, before the Internet of Things, and before network-connected everything, infrared was king. In the 90s, personal organizers, keyboards, Furbys, and critical infrastructure was built on infrared. Some of these devices are still around, hiding in plain sight. This means there’s a lot of opportunities for some very fun exploits. This was the focus of [Mike Ossmann] and [Dominic Spill]’s talk at this year’s Shmoocon, Exploring The Infrared World. What’s the hook? Using software-defined radio with terahertz frequencies.

irtra
[Dominic]’s infrared detector
Infrared communication hasn’t improved since the days of IrDA ports on laptops, and this means the hardware required to talk to these devices is exceptionally simple. The only thing you need is an IR phototransistor and a 4.7k resistor. This is enough to read signals, but overkill is the name of the game here leading to the development of the Gladiolus GreatFET neighbor. This add-on board for the GreatFET is effectively a software defined IR transceiver capable of playing with IrDA, 20 to 60 kHz IR remote control systems, and other less wholesome applications.

Demos are a necessity, but the world seems to have passed over IR in the last decade. That doesn’t mean there still aren’t interesting targets. A week before Shmoocon, [Mike Ossmann] put out the call on Twitter for a traffic light and the associated hardware. Yes, police cars and ambulances use infrared signaling to turn traffic lights green. You shouldn’t. You can, but you shouldn’t.

What was the takeaway from this talk? IR still exists, apparently. Yes, you can use it to send documents directly from your PalmPilot to a laser printer without any wires whatsoever. One of the more interesting applications for IR is an in-car wireless headphone unit that sends something almost, but not quite, like pulse coded audio over infrared. The demo that drew the most applause was an infrared device that changed traffic lights to green. The information to do that is freely available on the web, but you seriously don’t want to attempt that in the wild.

Light Dimmer Shows How to Steal Power from AC Line

We see a lot of traffic on the tips line with projects that cover old ground but do so in an instructive way, giving us insight into the basics of electronics. Sure, commercial versions of this IR-controlled light dimmer have been available for decades. But seeing how one works might just help you design your Next Big Thing.

Like many electronic controls, the previous version of this hack required a connection to a neutral in addition to the hot. This version of the circuit relies on passing a small current through the light bulb the dimmer controls to avoid that extra connection. This design limits application to resistive loads like incandescent bulbs. But it’s still a cool circuit, and [Muris] goes into great detail explaining how it works.

We think the neatest bit is the power supply that actually shorts itself out to turn on the load. A PIC controls a triac connected across the supply by monitoring power line zero-crossing. The PIC controls dimming by delaying the time the triac fires, which trims the peaks off of the AC waveform. The PIC is powered by a large capacitor while the triac is conducting, preventing it from resetting until the circuit can start stealing power again. Pretty clever stuff, and a nice PCB design to boot.

Given the pace of technological and cultural change, it might be that [Muris]’ dimmer is already largely obsolete since it won’t work with CFLs or LEDs. But we can see other applications for non-switched mode transformerless power supplies. And then again, we reported on [Muris]’s original dimmer back in 2009, so the basic design has staying power.

ESP-ing a Philips Sound System.

IoT-ifying old stuff is cool. Or even new, offline stuff. It seems to be a trend. And it’s sexy. Yes, it is. Why are people doing this, you may ask: we say why not? Why shouldn’t a toaster be on the IoT? Or a drill press? Or a radio? Yes, a radio.

[Dr. Wummi] just added another device to the IoT, the Internet of Thongs as he calls it. It’s a Philips MCM205 Micro Sound System radio. He wanted to automate his radio but his original idea of building a setup with an infrared LED to remotely control it failed. He blamed it to “some funky IR voodoo”.  So he decided to go for an ESP8266 based solution with a NodeMCU. ESP8266 IR remotes have been known to work before but maybe those were just not voodoo grade.

After opening the radio up, he quickly found that the actual AM/FM Radio was a separate module. The manufacturer was kind enough to leave the pins nicely labelled on the mainboard. Pins labelled SCL/SDA hinted that AM/FM module spoke I²C. He tapped in the protocol via Bus Pirate and it was clear that the radio had an EEPROM somewhere on the main PCB. A search revealed a 24C02 IC in the board, which is a 2K I²C EEPROM. So far so good but there were other functionalities left to control, like volume or CD playing. For that, he planned to tap into the front push button knob. The push button had different resistors and were wired in series so they generated different voltages at the main board radio ADC Pins. He tried to PWM with the NodeMCU to simulate this but it just didn’t work.

Continue reading “ESP-ing a Philips Sound System.”

Colorful, Touch-Sensitive Light Table is Ready for Gaming

It’s an ambitious build for sure — you don’t start with $500 worth of wood if you don’t intend for the finished product to dazzle. And this 240-pixel touch-sensitive light box coffee table does indeed dazzle.

Sometimes when we see such builds as these, fit and finish take a back seat to function. [dasdingo89] bucks that trend with a nicely detailed build, starting with the choice of zebrawood for the table frame. The bold grain and the frosted glass top make for a handsome table, but what lurks beneath the glass is pretty special too. The 240 WS2812 modules live on custom PCBs, each thoughtfully provided with connectors for easy service. There’s also an IR transmitter-receiver pair on each board to detect when something is placed over the pixel. The pixel boards are connected to custom-built shift register boards for the touch sensors, and an Arduino with Bluetooth runs the whole thing. Right now the table just flashes and responds to hand gestures, but you can easily see this forming the basis of a beautiful Tetris or Pong table.

This build reminds us a little of this pressure-sensitive light floor we featured recently, which also has some gaming possibilities. Maybe [dasdingo89] and  [creed_bratton_] should compare notes and see who can come up with the best games for their platform.

[via r/DIY and a tip from emptycanister]