RCA TV Gets New Life As Interactive Atltvhead

May 27, 2018 by Steven Dufresne 8 Comments

TVs are usually something you sit and passively watch. Not so for [Nate Damen’s] interactive, wearable TV head project, aka Atltvhead. If you’re walking around Atlanta, Georgia and you see him walking around with a TV where his head should be, introduce yourself! Or sign into Twitch chat and take control of what’s being displayed on the LEDs which he’s attached to the screen. Besides being wearable technology, it’s also meant to be an interactive art piece.

For this, his third version, the TV is a 1960’s RCA Victor Portable Television. You can see some of the TVs he found for previous versions on his hackaday.io page. They’re all truly vintage. He gutted this latest one and attached WS2812 LED strips in a serpentine pattern inside the screen. The LEDs are controlled by his code and the FastLED library running on an ESP8266. Power comes from four NiMH AA-format batteries, giving him 5 V, which he regulates down to 3.3 V. His phone serves as a WiFi hotspot.

[Nate] limits the commands so that only positive things can be displayed, a heart for example. Or you can tweak what’s being displayed by changing the brightness or make the LEDs twinkle. Judging by the crowds we see him attracting in the first video below, we’d say his project was a huge success. In the second video, Nate does a code walkthrough and talks about some of his design decisions.

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Disaster Area Communications With Cloud Gateways

May 26, 2018 by Brian Benchoff 24 Comments

2017, in case you don’t remember, was a terrible year for the Caribbean and Gulf coast. Hurricane Maria tore Puerto Rico apart, Harvey flooded Houston, Irma destroyed the Florida Keys, and we still haven’t heard anything from Saint Martin. There is, obviously, a problem to be solved here, and that problem is communications. Amateur radio only gets you so far, but for their Hackaday Prize entry, [Inventive Prototypes] is building an emergency communication system that anyone can use. It only needs a clear view of the sky, and you can use it to send SMS messages. It’s the PR-Holonet, and it’s something that’s already desperately needed.

The basis for the PR-Holonet is built around an Iridium satellite modem. To date, satellite communication is the best way to get a message out to the world without any infrastructure. It’ll work in the middle of the Sahara, the depths of the Amazon, and conveniently anywhere that was just hit by a category five hurricane.

Along with the Iridium modem, [Inventive Prototypes] is using standard, off-the-shelf equipment to turn that connection to a satellite network into something any smartphone can use. That means pulling out a Raspberry Pi, of course. But building a project for areas that were recently ravaged by hurricanes is no easy task. The enclosure it the key here, and [Inventive Prototypes] is using some great water-resistant, dust-proof junction boxes, solar panels, and a whole bunch of batteries to keep everything humming along. It’s a great project and something that was desperately needed a year ago.

An Ultrasound Driver With Open Source FPGAs

May 25, 2018 by Brian Benchoff 10 Comments

Ultrasound imaging has been around for decades, but Open Source ultrasound has not. While there are a ton of projects out there attempting to create open ultrasound devices, most of this is concentrated on the image-processing side of things, and not the exceptionally difficult problem of pinging a sensor at millions of times a second, listening for the echo, and running that through a very high speed ADC.

For his entry into the Hackaday Prize, [kelu124] is doing just that. He’s building an ultrasound board that’s built around Open Hardware, a fancy Open Source FPGA, and a lot of very difficult signal processing. It also uses some Rick and Morty references, so you know this is going to be popular with the Internet peanut gallery.

The design of the ultrasound system is based around an iCE40 FPGA, the only FPGA with an Open Source toolchain. Along with this, there are a ton of ADCs, a DAC, pulsers, and a high voltage section to drive the off-the-shelf ultrasound head. If you’re wondering how this ultrasound board interfaces with the outside world, there’s a header for a Raspberry Pi on there, too, so this project has the requisite amount of blog cred.

Already, [kelu] has a working ultrasound device capable of sending pulses out of its head and receiving the echo. Right now it’s just a few pulses, but this is a significant step towards a real, working ultrasound machine built around a reasonably Open Source toolchain that doesn’t cost several arms and legs.

Programmable Air Makes Robotics A Breeze

May 24, 2018 by Kristina Panos 10 Comments

[Amitabh] was frustrated by the lack of options for controlling air pressure in soft robotics. The most promising initiative, Pneuduino, seemed to be this close to a Shenzhen production run, but the creators have gone radio silent. Faced with only expensive alternatives, he decided to take one for Team Hacker and created Programmable Air, a modular system for inflatable and vacuum-based robotics.

The idea is to build the cheapest, most hacker-friendly system he can by evaluating and experimenting with all sorts of off-the-shelf pumps, sensors, and valves. From the looks of it, he’s pretty much got it dialed in. Programmable Air is based around $9 medical-grade booster pumps that are as good at making vacuums as they are at providing pressurization. The main board has two pumps, and it looks like one is set to vacuum and the other to spew air. There’s an Arduino Nano to drive them, and a momentary to control the air flow.

Programmable Air can support up to 12 valves through daughter boards that connect via right-angle header. In the future, [Amitabh] may swap these out for magnetic connections or something else that can withstand repeated use.

Blow past the break to watch Programmable Air do pick and place, control a soft gripper, and inflate a balloon. The balloon’s pressurization behavior has made [Amitabh] reconsider adding a flow meter, but so far he hasn’t found a reasonable cost per unit. Can you recommend a small flow meter that won’t break the bank? Let us know in the comments.

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Open Source Underwater Distributed Sensor Network

May 23, 2018 by Steven Dufresne 32 Comments

One way to design an underwater monitoring device is to take inspiration from nature and emulate an underwater creature. [Michael Barton-Sweeney] is making devices in the shape of, and functioning somewhat like, clams for his open source underwater distributed sensor network.

The clams contain the electronics, sensors, and means of descending and ascending within their shells. A bunch of them are dropped overboard on the surface. Their shells open, allowing the gas within to escape and they sink. As they descend they sample the water. When they reach the bottom, gas fills a bladder and they ascend back to the surface with their data where they’re collected in a net.

Thus far he’s made a few clams using acrylic for the shells which he’s blown himself. He soldered the electronics together free-form and gave them a conformal coating of epoxy. He’s also used a thermistor as a stand-in for other sensors and is already working on a saturometer, used for measuring the total dissolved gas (TDG) in the water. Knowing the TDG is useful for understanding and mitigating supersaturation of water which can lead to fish kills.

He’s also given a lot of thought into the materials used since some clams may not make it back up and would have to degrade or be benign where they rest. For example, he’s been using a lithium battery for now but would like to use copper on one shell and zinc on another to make a salt water battery, if he can make it produce enough power. He’s also considering using 3D printing since PLA is biodegradable. However, straight PLA could be subject to fouling by underwater organisms and would require cleaning, which would be time-consuming. PLA becomes soft when heated in a dishwasher and so he’s been looking into a PLA and calcium carbonate filament instead.

Check out his hackaday.io page where he talks about all these and more issues and feel free to make any suggestions.

Inverted Pendulum For The Control Enthusiast

May 20, 2018 by Bryan Cockfield 21 Comments

Once you step into the world of controls, you quickly realize that controlling even simple systems isn’t as easy as applying voltage to a servo. Before you start working on your own bipedal robot or scratch-built drone, though, you might want to get some practice with this intricate field of engineering. A classic problem in this area is the inverted pendulum, and [Philip] has created a great model of this which helps illustrate the basics of controls, with some AI mixed in.

Called the ZIPY, the project is a “Cart Pole” design that uses a movable cart on a trolley to balance a pendulum above. The pendulum is attached at one point to the cart. By moving the cart back and forth, the pendulum can be kept in a vertical position. The control uses the OpenAI Gym toolkit which is a way to easily use reinforcement learning algorithms in your own projects. With some Python, some 3D printed parts, and the toolkit, [Philip] was able to get his project to successfully balance the pendulum on the cart.

Of course, the OpenAI Gym toolkit is useful for many more projects where you might want some sort of machine learning to help out. If you want to play around with machine learning without having to build anything, though, you can also explore it in your browser.

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Autonomous Agribots For Agriculture

May 18, 2018 by Brian Benchoff 16 Comments

For his Hackaday Prize entry, [TegwynTwmffat] is going all-in on autonomous robotics. No, it’s not a self-driving car with highly advanced features such as cruise control with lane-keeping. This is an autonomous robot that’s capable of driving itself. It’s a robot built for agriculture, and relative to other autonomous robotics projects, this one is huge. It’s the size of a small tractor.

The goal [Tegwyn]’s project is to build a robot capable of roving fields of crops to weed, harvest, and possibly fertilize the land. This is a superset of the autonomous car problem: not only does [Tegwyn] need to build a chassis to roll around a field, he needs accurate sensors, some sort of connection to the Internet, and a fast processor on board. The mechanical part of this build comes in the form of a rolling chassis that’s a bit bigger than a golf cart, and electrically powered (although there is a small Honda generator strapped to the back). The electronics is where this gets really interesting, with a rather large board built to house all the sensor and wireless modules, with everything controlled by a TC275, a multicore, 32-bit microcontroller that also has the world record for solving a Rubik’s cube.

Already, [Tegwyn] has a chassis and motor set up, and is already running some code to allow for autonomous navigation. It’s not much now — just rolling down a garden path — but then again, if you’re building a robot for agriculture, it’s not that hard to roll around an open field. You can check out a video of the bot in action below.

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