Infrared Following Robot Built As Proof-of-Concept For Autonomous Luggage

Once upon a time, the poor humans of the past had to lug around suitcases and trunks with their own arms. Then, some genius figured out that you could just put wheels on and make everyone’s life a million times easier. Now, what if you didn’t even have push, because your luggage could just follow you instead? Well, students [Yuqiang Ge] and [Yiyang Zhao] have figured out a proof of concept for how that could work.

Their build is a small robotic platform that they assembled for their ECE5730 final project. The tiny wheeled robot is programmed to rotate on the spot until its infrared sensors pick up a signal. In turn, the user is intended to carry an infared beacon for it to lock onto. A pair of sensors are used on the robot platform, separated by a board to serve as a blind. The robot determines the relative signal strength from each sensor, and uses that to vary PWM signals to the two DC drive motors to steer the robot platform to seek and follow the infrared beacon.

It’s a neat idea, and looks to work pretty well in a university corridor. It even has an ultrasonic range sensor to (ideally) stop when it gets too close to the user. Whether it would survive the tumult of a crowded airport is another thing entirely, but that’s what the engineering process is about. Indeed, the very concept has been commercialized already!

Following-robots are a common student project, and one well worth exploring if you’re new to the robotic field.

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Drone Motion Capture, The Open Source Way

If you want to do some really advanced flying with drones, you typically need to be able to track them in space. [Joshua Bird] has whipped up a drone tracking system that can do the job for as little as $20 with millimeter-scale precision.

The system uses four PS3 Eye cameras which can be had second-hand at a cost of just $5 each. They’re modified by removing their IR cut filter, and putting in an IR-passing filter in the form of a cut-up slice of floppy disk. The system tracks the drones via their infrared indicators and the known locations of the four cameras themselves, which the system is capable of mapping out automatically. By using four cameras, the system is robust in the event the view of a camera is occluded. The system can track multiple drones at the same time, with [Joshua] demonstrating it working with two drones each carrying three infrared markers. He has the system set up to send positional updates to ESP32 microcontrollers on the drones themselves, which command the drones to hold them in set positions.

Code is available on GitHub for the curious. We’ve seen other similar work before, too.

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Four images in as many panes. Top left is a fuchsia bottle with a QR code that only shows up on the smartphone screen held above it. Top right image is A person holding a smartphone over a red wristband. The phone displays a QR code on its screen that it sees but is invisible in the visible wavelengths. Bottom left is a closeup of the red wristband in visible light and the bottom right image is the wristband in IR showing the three QR codes embedded in the object.

Fluorescent Filament Makes Object Identification Easier

QR codes are a handy way to embed information, but they aren’t exactly pretty. New work from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have a new way to produce high contrast QR codes that are invisible. [PDF]

If this sounds familiar, you may remember CSAILs previous project embedding QR codes into 3D prints via IR-transparent filament. This followup to that research increases the detection of the objects by using an IR-fluorescent filament. Another benefit of this new approach is that while the InfraredTags could be any color you wanted as long as it was black, BrightMarkers can be embedded in objects of any color since the important IR component is embedded in traditional filament instead of the other way around.

One of the more interesting applications is privacy-preserving object detection since the computer vision system only “sees” the fluorescent objects. The example given is marking a box of valuables in a home to be detected by interior cameras without recording the movements of the home’s occupants, but the possibilities certainly don’t end there, especially given the other stated application of tactile interfaces for VR or AR systems.

We’re interested to see if the researchers can figure out how to tune the filament to fluoresce in more colors to increase the information density of the codes. Now, go forth and 3D print a snake with snake in a QR code inside!

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Cooling Paint You Can Actually Make

[NightHawkInLight] has been working on radiative sky paint. (Video, embedded below.) That’s a coating that radiates heat in the infrared spectrum at a wavelength that isn’t readily absorbed or reflected by the atmosphere. The result is a passive system that keeps materials a few degrees cooler in direct sunlight than an untreated piece in the shade. That sounds a bit like magic, but apparently the math checks out.

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A blue PCB remote control

The Remoteduino Nano Is A Tiny IR Remote That’s Truly Universal

Universal remotes are extremely convenient if they work correctly. But setting them up can be quite a hassle: often, you need to browse through long lists of TV models, key in the codes on the remote with just a blinking LED as confirmation, and then pray that the manufacturer included the correct codes for all your equipment. IR isn’t a very complicated technology, however, so it’s perfectly possible to roll your own universal remote, as [sjm4306] shows in his latest project, the Remoteduino Nano. It’s a fully programmable IR remote that gives you maximum flexibility when emulating the codes for those obscure A/V systems scattered around your home.

The remote runs on an ATmega328p in a tiny QFN package, which drives a standard 5 mm IR LED through a transistor. Eight buttons are available to the user, which can be freely mapped to any desired code. A five-pin header is included to program the ATmega through its serial port. However, this was mainly done to help debug – a user who only needs to program the device once would typically use a pogo-pin-based adapter instead.

Currently, codes can only be programmed through the serial port, but there’s also an IR receiver present that can be used to copy codes from an existing remote. [sjm4306] hasn’t implemented this feature in software yet, but will probably do so in a future update of the project’s Arduino sketch. If you’re impatient, you can also have a go at it yourself since all code and the board’s Gerber files are freely available for download.

Its tiny size makes the Remoteduino Nano a convenient tool to keep in your drawer if you like to tinker with A/V systems and keep losing those remotes. The Nano is actually an improved version of the original Remoteduino project that [sjm4306] developed a couple of years ago. The problem of a truly universal remote is one that dates back several decades, however.

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Reliable 3D Printing With Ceramic Slurry

3D printing is at its most accessible (and most affordable) when printing in various plastics or resin. Printers of this sort are available for less than the cost of plenty of common power tools. Printing in materials other than plastic, though, can be a bit more involved. There are printers now for various metals and even concrete, but these can be orders of magnitude more expensive than their plastic cousins. And then there are materials which haven’t really materialized into a viable 3D printing system. Ceramic is one of those, and while there are some printers that can print in ceramic, this latest printer makes some excellent strides in the technology.

Existing technology for printing in ceramic uses a type of ceramic slurry as the print medium, and then curing it with ultraviolet light to solidify the material. The problem with ultraviolet light is that it doesn’t penetrate particularly far into the slurry, only meaningfully curing the outside portions. This can lead to problems, especially around support structures, with the viability of the prints. The key improvement that the team at Jiangnan University made was using near-infrared light to cure the prints instead, allowing the energy to penetrate much further into the material for better curing. This also greatly reduces or eliminates the need for supports in the print.

The paper about the method is available in full at Nature, documenting all of the details surrounding this new system. It may be a while until this method is available to a wider audience, though. If you can get by with a print material that’s a little less exotic, it’s not too hard to get a metal 3D printer, as long as you are familiar with a bit of electrochemistry.

Op-Amp Challenge: Interactive Analog LED Wave Array

A while back, [Chris Lu] was studying how analog circuits, specifically op-amps can be used to perform mathematical operations and wondered if they could be persuaded to solve differential equations, such as the wave equation. After sitting on the idea for a few years, it was time to make it a reality, and the result is an entry into the Op-Amp Challenge.

Unlike many similar interactive LED matrix displays that are digital in nature (because it’s a lot easier), this design is pure analog, using many, many op-amps. A custom PCB houses a 4×4 array of compute units, each with a blue and white LED indicating the sign and magnitude of the local signal.

The local input signal is provided by an IR photodiode, AC coupled to only respond to change, with every other circuit sharing a sensor to keep it simple. Each circuit is connected to its immediate neighbors on the PCB, and off the PCB via board-to-board connectors. This simple scheme makes this easily scalable if desired in the future.

[Chris] does a great job of breaking down the math involved, which makes this project a neat illustration of how op-amp circuits can implement complex mathematical problems in an easy-to-understand process. Even more op-amps are pressed into service for generating the split-rail voltage reference and for amplifying the weak photodiode signals, but the computation circuit is the star of the show.

We like analog computing a fair bit around these parts. Here’s a little something we were previously drooling over.

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