Robotic Fish Swarm Together Using Cameras And LEDs

Robotics has advanced in leaps and bounds over the past few decades, but in terms of decentralized coordination in robot swarms, they far behind biological swarms. Researchers from Harvard University’s Weiss Institute are working to close the gap, and have developed Blueswarm, a school of robotic fish that can exhibit swarm behavior without external centralized control.

In real fish schools, the movement of an individual fish depends on those around it. To allow each robotic fish to estimate the position of its neighbors, they are equipped with a set of 3 blue LEDs, and a camera on each side of the body. Four oscillating fins, inspired by reef fish, provide 3D control. The actuator for the fins is simply a pivoting magnet inside a coil being fed an alternating current. The onboard computer of each fish is a Raspberry Pi W, and the cameras are Raspberry Pi Camera modules with wide-angle lenses. Using the position information calculated from the cameras, the school can coordinate its movements to spread out, group together, swim in a circle, or find an object and then converge on it. The full academic article is available for free if you are interested in the details.

Communication with light is dependent on the clarity of the medium it’s traveling through, in this case, water — and conditions can quickly become a limiting factor. Submarines have faced the same challenge for a long time. Two current alternative solutions are ELF radio and sound, which are both covered in [Lewin Day]’s excellent article on underwater communications.

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Building The Ultimate Raspberry Pi Automation Controller

At this point, we’ve lost count of how many automation projects we’ve seen with some variant of a Raspberry Pi at the helm. Which is hardly surprising, as the boards are cheap, powerful, and well documented. The list of reasons not to use one has never been very long, but with the PiCon One that [Frank] has been working on, it’s about to get even shorter.

The project takes the form of an IP65 industrial enclosure and support electronics that the Raspberry Pi Zero W plugs into. While expandable in nature, [Frank] has a core set of features he’s aiming for as a baseline such as additional serial ports, integrated uninterruptible power supply, a battery-backed Real Time Clock (RTC), an array of programmable status LEDs, and support for XBee and GPS plug-in modules. Feedback is provided through a pair of four digit seven-segment displays and a color 320×480 TFT screen running a custom user interface.

[Frank] envisions the PiCon One for use as a rugged solar power controller, eventually able to measure array output, energy consumption, and even operate motorized mounts to keep the panels pointed at the sun. To that end, he’s recently been experimenting with running JPL’s Horizon software on the Pi to determine the sun’s position in real-time. But the device is capable of so much more, and would make an ideal controller for many home and potentially even industrial applications.

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Portable Video Looper Is Easy As Pi

We all have handfuls of thumb drives lying around with only a vague idea of what’s on most of them, right? So why not dust one off, back it up somewhere, and give it a new purpose? That’s exactly what [Cher_Guevara] did to make this portable Raspberry Pi video looper. The hardest part of recreating this one might be coming up with such a good candidate mini CRT TV.

Once powered on, the Pi Zero W stuffed inside this baby Magnavox waits for a thumb drive to be inserted and says as much in nice green text on the screen. Then it displays the number of video files found on the drive and gives a little countdown before looping them all endlessly.

We love how flawlessly [Cher] was able to integrate the USB port and a flush-mounted shutdown button for the Pi into the TV’s control panel on the top. It’s like a portable from another timeline.

[Cher] got lucky because this TV happens to have a video-in jack for connecting up the Pi. If yours doesn’t have one, you might be able to use an RCA to RF converter if the antenna is removable. We’ve got the demo video waiting for you after these messages.

Okay, that’s one thumb drive repurposed. Now find another and experiment with adding USB OtG to it.

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Raspberry Pi Plays A MIDI Tune Wherever You May Roam

MIDI controller keyboards are great because they let you control any synthesizer you plug them into. The only downside: you need a synthesizer to turn MIDI notes into actual sounds, slightly complicating some summer night campfire serenading. Not for [Geordie] though, who decided to build the nanoPi, a portable, MIDI instrument housing a Raspberry Pi.

Using a Korg nanoKEY2 USB MIDI controller as base for the device, [Geordie] took it apart and added a Raspberry Pi Zero W, a power bank to, well, power it, and a USB hub to connect a likewise added USB audio interface, as well as the controller itself. As the nanoKEY2 has a naturally slim shape, none of this would ever fit in it, so he designed and 3D printed a frame to extend its height. Rather than wiring everything up internally, he decided to route the power and data cable to the outside and connect them back to the device itself, allowing him to use both the power bank and the controller itself separately if needed.

On the software side, the Pi is running your common open source software synthesizer, Fluidsynth. To control Fluidsynth itself — for example to change the instrument — [Geordie] actually uses the Termius SSH client on his phone, allowing him also to shut down the Pi that way. While Fluidsynth’s built-in MIDI router could alternatively remap the nanoKEY2’s additional buttons, it appears the functionality is limited to messages of the same type, so the buttons’ Control Change messages couldn’t be remapped to the required Program Change messages. Well, there’s always the option to fit some extra buttons if needed. Or maybe you could do something clever in software.

As you may have noticed, the nanoPi doesn’t include any speaker — and considering its size, that’s probably for the best. So while it’s not a fully standalone instrument, it’s a nice, compact device to use with your headphones anywhere you go. And thanks to its flexible wiring, you could also attach any other USB MIDI controller to it, such as this little woodwind one, or the one that plays every pop song ever.

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Easy Internet For Retro Computers With The PiModem

Retro computers are great, but what really makes a computer special is how many other computers it can talk to. It’s all about the network! Often, getting these vintage rigs online requires a significant investment in dusty old network cards from eBay and hunting down long-corrupted driver discs to lace everything together. A more modern alternative is to use something like PiModem to do the job instead.

PiModem consists of using a Raspberry Pi Zero W to emulate a serial modem, providing older systems with a link to the outside world. This involves setting up the Pi to use its hardware serial port to communicate with the computer in question. A level shifter is usually required, as well as a small hack to enable hardware flow control where necessary. It’s then a simple matter of using tcpser and pppd so you can talk to telnet BBSs and the wider Internet at large.

It’s a tidy hack that makes getting an old machine online much cheaper and easier than using hardware of the era. We’ve seen similar work before, too!

Coffee Maker Gives Plants An Automatic Drip

Somehow, [Jeremy S   Cook]’s wife was able to keep a Keurig machine going for 10 years before it quit slinging caffeine. [Jeremy] got it going again, but decided to buy a new one when he saw how it was inside from a decade of water deposits.

But why throw the machine out like spent coffee grinds? Since the pump is still good, he decided to turn it into an automatic plant watering machine. Now the Keurig pumps water using a Raspberry Pi Zero W and a transistor. [Jeremy] can set up watering cron jobs with PuTTY, or push water on demand during dry spells. We love that he wired up a soil moisture sensor to the red/blue LEDs around the brew button — red means the plant is thirsty, purple means water is flowing, and no light means the plant is quenched and happy.

This project is wide open, but cracking into the Keurig is up to you. Fortunately, that part of the build made it into the video, which is firmly planted after the break.

Old coffee makers really do seem suited to taking up plant care in retirement. Here’s a smart garden made from an espresso machine.

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A Thermal Camera With A Vintage Twist

Nowadays we often value the superb design of vintage technology. It is, therefore, laudable when a broken piece of old electronics is given a new purpose. These types of builds are exactly [Martin Mander’s] cup of tea as he confirmed by turning a 1979 Apollo microwave monitor into a thermal camera (video embedded below).

Intrigued by its unique design, [Martin Mander] picked up the original microwave monitor at a secondhand sale, although the device was not exactly in mint condition. Supposedly this type of detector was used to monitor the exposure of personnel to microwave radiation in an industrial environment.

After removing all the guts, he replaced them with a Raspberry Pi Zero W, Adafruit thermal camera, 1.3″ TFT display, and a USB battery pack. It is especially nice that [Martin Mander] was able to mount all the components without relying on 3D prints but instead, he hand-carved some custom panels and brackets from waste plastic.

The software is based on Python and automatically uploads the captured images to an Adafruit.IO dashboard. With 8 x 8 pixels the resolution of the sensor is not great but by using bicubic interpolation he was able to convert it to a 32 x 32 image which was enough to take some interesting pictures of his cat and other household items.

It is also worthwhile to check out some of [Martin Manders] other retro-tech mods like his cassette Pi IoT scroller.

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