Reflective Sensor Becomes Kart Racing Lap Counter

Once you have a track and a kart to race on it, what’s missing? A lap counter that can give your lap times in hardcopy, obviously! That’s what led [the_anykey] to create the Arduino-based Lap Timer to help him and his kids trim those precious seconds off their runs, complete with thermal printer for the results.

The hardware uses an infrared break-beam sensor module (a Velleman PEM10D) to detect when a kart passes by. This module is similar to a scaled-up IR reflective object sensor; it combines an IR emitter and receiver on one end, and is pointed at a reflector placed across the track, up to 10 meters away. When a kart breaks the beam, the module reports the event to the rest of the hardware. Only needing electronics on one side allows the unit to be self-contained.

An obvious shortcoming of this system is the inability to differentiate between multiple karts, but for timing a single driver’s performance it does the trick. What’s great about this project is it showcases how accessible hardware is today; a device like this is possible to put together with what are essentially off-the-shelf components available to any hobbyist, using an Arduino as the glue to hold it together. We’d only comment that a red-tinted piece of plastic as an overlay for the red display (and a grey-tinted one for the green) would make the LED displays much easier to read. Still, this is a very clean and well-documented build. See it in action in the video embedded below.

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Line Follower has Lots of recycled Parts, but Zero Brains

Line Followers are a tried-and-true type of robot; both hardware and software need to be doing their job in harmony in order to be successful at a clearly defined physical task. But robots don’t always have microcontrollers and software, as [Mati_DIY]’s zero programming analog line follower demonstrates.

For readers used to seeing a Raspberry Pi or Arduino in almost everything, an analog robot whose “programming” exists only as a harmony between its discrete parts can be an eye-opener as well as an accessible project. A video of the robot in action is embedded below.

[Mati_DIY]’s design uses two CNY70 reflective sensors (which are essentially infrared emitter/phototransistor pairs) and an LM358 dual op-amp. Together, the sensors act as two near-sighted eyes. By using the output of each sensor to drive a motor via a transistor, the presence or absence of the black line is directly and immediately reflected by the motion of the attached motor. The more black the sensor sees, the more the motor turns. Electrically, that’s all that happens; but by attaching the right sensor to the left motor and the left sensor to the right motor, you get a robot that always tries to keep the black line centered under the sensors. Playing with the spacing of the motors and sensors further tweaks the performance.

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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.

HackBusting: Can you Fake a TV Remote with a Lighter and some Paper?

We recently published an article where someone apparently controlled their TV by simulating a remote with merely a lighter and a sheet of paper. The paper had a barcode like cutout for a supposed “Universal Standby Signal”. The video rightfully attracted a substantial crowd, some awestruck by its simplicity, others sceptical about its claims.

Coming from some generic “Viral Life Hack” production house, the characteristic blare of background music, more suited to an underground rave than a technical video, certainly did not do it any favours. As any moderately experienced campaigner would know, modern televisions and remotes have been carefully engineered  to prevent such mishaps. Many of us at Hackaday, were under the impression that it would take something slightly more sophisticated than a fluorescent-bodied lighter and a crisp sheet of A4 to deceive the system. So we tested it out. Our verdict? Unlikely, but not impossible. (And we’re pretty sure that the video is a fake either way.) But enough speculation, we’re here to do science.

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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.

[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.

Hacked Television Uses No Power In Standby Mode

How much effort do you put into conserving energy throughout your daily routine? Diligence in keeping lights and appliances turned off are great steps, but those selfsame appliances likely still draw power when not in use. Seeing the potential to reduce energy wasted by TVs in standby mode, the [Electrical Energy Management Lab] team out of the University of Bristol have designed a television that uses no power in standby mode.

The feat is accomplished through the use of a chip designed to activate at currents as low as 20 picoamps.  It, and a series of five photodiodes, is mounted in a receiver which attaches to the TV. The receiver picks up the slight infrared pulse from the remote, inducing a slight current in the receiving photodiodes, providing enough power to the chip which in turn flips the switch to turn on the TV. A filter prevents ambient light from activating the receiver, and while the display appears to take a few seconds longer to turn on than an unmodified TV, that seems a fair trade off if you aren’t turning it on and off every few minutes.

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This Miniscule IR to HID Keyboard Hides in a Key Cap

Shards of silicon these days, they’re systematically taking what used to be rather complicated and making it dead simple in terms of both hardware and software. Take, for instance, this IR to HID Keyboard module. Plug it into a USB port, point your remote control at it, and you’re sending keyboard commands from across the room.

To do this cheaply and with a small footprint used to be the territory of bit-banging software hacks like V-USB, but recently the low-cost lines of microcontrollers that are anything but low-end have started speaking USB in hardware. It’s a brave new world.

In this case we’re talking about the PIC18F25J50 which is going to ring in at around three bucks in single quantity. The other silicon invited to the party is an IR receiver (which demodulates the 38 kHz carrier signal used by most IR remotes) with a regulator and four passives to round out the circuit. the board is completely single-sided with one jumper (although the IR receiver is through-hole so you don’t quite get out of it without drilling). All of this is squeezed into a space small enough to be covered by a single key cap — a nice touch to finish off the project.

[Suraj] built this as a FLIRC clone — a way to control your home-built HTPC from the sofa. Although we’re still rocking our own HTPC, it hasn’t been used as a front-end for many years. This project caught our attention for a different reason. We want to lay down a challenge for anyone who is attending SuperCon (or not attending and just want to show off their chops).

This is nearly the same chip as you’ll find on the SuperCon badge. That one is a PIC18LF25K50, and the board already has an IR receiver on it. Bring your PIC programmer and port this code from MikroC over to MPLAB X for the sibling that’s on the badge and you’ll get the hacking cred you’ve long deserved.

[via Embedded Lab]