Raspberry Pi Balloon Goes Too High, Goes Boom, But Survives

Some people like to get high on a Wednesday afternoon. [Kevin Hubbard] of Black Mesa Labs likes to get really high. Even higher than intended: last month, he flew a helium balloon powered by a Raspberry Pi to 103,000 feet. It was only supposed to go to 90,000, but a fault in the code for the controller meant that it went higher, burst and plunged to the ground. All thanks to an extra hash mark in his code.

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Chess Computers Improve Since 90s

The AlphaGo computer has been in the news recently for beating the top Go player in the world in four out of five games. This evolution in computing is a giant leap from the 90s when computers were still struggling to beat humans at chess. The landscape has indeed changed, as [Folkert] shows us with his chess computer based on a Raspberry Pi 3 and (by his own admission) too many LEDs.

The entire build is housed inside a chess board with real pieces (presumably to aid the human player) and an LED on every square. When the human makes a move, he or she inputs it into the computer via a small touch screen display. After that, the computer makes a move, indicated by lighting up the LEDs on the board and printing the move on the display. The Raspberry Pi is running the embla chess program, which has an Elo strength of about 1600.

While the computer isn’t quite powerful enough to beat Magnus Carlsen, we can only imagine how much better computers will be in the future. After all, this credit-card sized computer is doing what supercomputers did only a few decades ago. With enough Raspberry Pis, you might even be able to beat a grandmaster with your chess computer. Computer power aside, think of the advancements in fabrication technology (and access to it) which would have made this mechanical build a wonder back in the 90s too.

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K.I.S.S. Pi Sprinkler – Just Keep the Plants Alive

A good first step in a project is knowing what you want to do. [Ben Fino] made it clear that his Raspberry Pi Sprinkler control system for his wife’s garden had one goal: keep the plants alive. The resulting project is doing just that and no more.

The circuitry, and plumbing, is straightforward and explained well in the Instructable. All the electronics consists of is the Pi and a MOSFET to take the 3.3v GPIO to 5v to control a relay. The valve controlling the water requires 28v AC which necessitated the relay to control it. There are also three LEDs: one is for power, one to indicate when the valve is opened, and one is an extra for some future purpose.

The intriguing part is the use of weather data from the web to determine if it’s rained recently. Python scripts provided by [Ben’s] friend [Mark Veillette] use a weather site API to get the rainfall data. The main script is set to run once every 24 hours. [Ben] set his system to water unless the previous day had sufficient rain. How much rain and the number of look-back days is programmable.

What a great application of the KISS principle: keep it simple, stupid – except for that third LED without a purpose.

Don’t Take Photos of Your Arduino 101 Either, It’s Light Sensitive

Wafer level chips are cheap and very tiny, but as [Kevin Darrah] shows, vulnerable to bright light without the protective plastic casings standard on other chip packages.

We covered a similar phenomenon when the Raspberry Pi 2 came out. A user was taking photos of his Pi to document a project. Whenever his camera flash went off, it would reset the board.

[Kevin] got a new Arduino 101 board into his lab. The board has a processor from Intel, an accelerometer, and Bluetooth Low Energy out of the box while staying within the same relative price bracket as the Atmel versions. He was admiring the board, when he noticed that one of the components glittered under the light. Curious, he pulled open the schematic for the board, and found that it was the chip that switched power between the barrel jack and the USB. Not only that, it was a wafer level package.

So, he got out his camera and a laser. Sure enough, both would cause the power to drop off for as long as the package was exposed to the strong light. The Raspberry Pi foundation later wrote about this phenomenon in more detail. They say it won’t affect normal use, but if you’re going to expose your device to high energy light, simply put it inside a case or cover the chip with tape, Sugru, or a non-conductive paint to shield it.

EDIT: [Kevin] also tested it under the sun and found conditions in which it would reset. Videos after the break.

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An Open Source Lead Tester

If you’ve ever needed an example of colossal failure of government actors, you need only to look at Flint, Michigan’s water crisis. After the city of Flint changed water supplies from Detroit to the Flint river, city officials failed to add the correct corrosion inhibitors. This meant that lead dissolved into the water, thousands of children were exposed to lead in drinking water, a government coverup ensued, [Erin Brockovich] showed up, the foreman of the Flint water plant was found dead, and the City Hall office containing the water records was broken into.

Perhaps inspired by Flint, [Matthew] is working on an Open Source Lead Tester for his entry into the 2016 Hackaday Prize.

[Matthew]’s lead tester doesn’t test the water directly. Instead, it uses a photodiode and RGB LED to look at the color of a lead test strip. These results are recorded, and with a bit of a software backend, an entire city can be mapped for lead contamination in a few days with just a few of these devices.

One problem [Matthew] has run into is the fact the Pi does not have analog to digital conversion, making reading a photodiode a little harder than just plugging a single part into a pin header and watching an analog value rise and fall. That really shouldn’t be a problem – ADCs are cheap, especially if you only need a single channel of analog input with low resolution. [Matthew] is also looking into using the Pi webcam for measuring the lead test strip. There are a lot of decisions to make, but any functional device that comes out of this project will be very useful in normal, functioning governments. And hopefully in Flint, Michigan too.

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Connect All Your IoT Through Your Pi 3

If you’re playing Hackaday Buzzword Bingo, today is your lucky day! Because not only does this article contain “Pi 3” and “IoT”, but we’re just about to type “ESP8266” and “home automation”. Check to see if you haven’t filled a row or something…

Seriously, though. If you’re running a home device network, and like us you’re running it totally insecurely, you might want to firewall that stuff off from the greater Interwebs at least, and probably any computers that you care about as well. The simplest way to do so is to keep your devices on their own WiFi network. That shiny Pi 3 you just bought has WiFi, and doesn’t use so much power that you’d mind leaving it on all the time.

Even if you’re not a Linux networking guru, [Phil Martin]’s tutorial on setting up the Raspberry Pi 3 as a WiFi access point should make it easy for you to use your Pi 3 as the hub of your IoT system’s WiFi. He even shows you how to configure it to forward your IoT network’s packets out to the real world over wired Ethernet, but if you can also use the Pi 3 as your central server, this may not even be necessary. Most of the IoT services that you’d want are available for the Pi.

Those who do want to open up to the world, you can easily set up a very strict firewall on the Pi that won’t interfere with your home’s normal WiFi. Here’s a quick guide to setting up iptables on the Pi, but using even friendlier software like Shorewall should also get the job done.

Still haven’t filled up your bingo card yet? “Arduino!”

Autograph: A String Art Printer

“String Art” is the name of the art form that transforms thousands of nails and just as many feet of thread into unique masterpieces. Some artists have developed techniques to create photorealistic string art works, but until now, there was no way around the tedious and time-consuming manufacturing process. Depending on the size, it can take months to complete a single piece by hand.

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