Hackaday Prize Entry: Environmental Regulation

A while back, [Kyle] wanted to grow gourmet mushrooms. The usual way of doing this is finding a limestone cave and stinking up half the county with the smell of manure. Doing this at home annoys far fewer neighbors, leading him to create a device that will regulate temperature, humidity, and carbon dioxide concentration. It’s called Mycodo, and it’s one of the finalists for the Automation portion of the Hackaday Prize.

Mycodo is designed to read sensors and activate relays, and when it comes to environmental sensors, there’s no shortage of sensors available. Right now, Mycodo has support for the usual DHT11 and DHT22 temperature and humidity sensors, HTU21D, AM2315, SHT* DS18B, and infrared sensors like the TMP006 and TMP007. These are connected to a Raspberry Pi equipped with a 7-inch touchscreen and a few relays to turn power outlets on and off. It’s not a complete system, though: think of it as a firmware for a 3D printer – the firmware doesn’t give you a 3D printer, it just makes building your own much easier.

Already Mycodo has been used for a few environmental control issues in addition to growing mushrooms. It was used to control the humidity in a bat cave – for real bats, not some cosplay thing – and a temperature- and humidity-regulated apiary. With the right environmental control system, there’s nothing you can’t do, and we’re glad to have Mycodo in the running for the Hackaday Prize.

Mega-Plate Petri-Dish Lets You Watch The Evolution Of Bacteria

Rearchers of the Harvard Medical School built a 2 feet by 4 feet (61 x 122 cm) large petri-dish to visualize the evolution of bacteria. Their experiment induces mutations in E. coli bacteria by exposing them to gradually increasing concentrations of antibiotics.

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3D Printed Door Latch has One Moving Part – Itself!

A group at the Hasso-Plattner Institute in Germany explored a curious idea: using 3D printed material not just as a material – but as a machine in itself. What does this mean? The clearest example is the one-piece door handle and latch, 3D printed on an Ultimaker 2 with pink Ninjaflex. It is fully functional but has no moving parts (besides itself) and has no assemblies. In other words, the material itself is also the mechanism.

The video (embedded below) showcases some similar concept pieces: door hinges, a pair of pliers, a pair of walker legs, and a pantograph round out the bunch. Clearly the objects aren’t designed with durability or practicality in mind – the “pliers” in particular seem a little absurd – but they do demonstrate different takes on the idea of using a one-piece item’s material properties as a functional machine in itself.

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Robotic Arm from Cardboard

Google showed the world that you could make a virtual reality headset from cardboard. We figure that might have been [Uladz] inspiration for creating a robotic arm also made out of cardboard. He says you can reproduce his design in about two hours.

You’ll need an Arduino and four hobby servo motors. The cardboard doesn’t weigh much, so you could probably use fairly small motors. In addition to the cardboard, there’s a piece of hardboard for the base and a few metal clips. You can control it all from the Arduino program or add an IR receiver if you want to run it by remote control. There’s a video of the arm–called CARDBIRD–in action, below.

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MIT Researchers Can Read Closed Books (and defeat CAPTCHA)

Ten years ago, MIT researchers proved that it was possible to look through an envelope and read the text inside using terahertz spectroscopic imaging. This research inspired [Barmak Heshmat] to try the same technique to read a book through its cover. A new crop of MIT researchers led by [Heshmat] have developed a prototype to do exactly that, and he explains the process in the video after the break. At present, the system is capable of correctly deciphering individual letters through nine pages of printed text.

They do this by firing terahertz waves in short bursts at a stack of pages and interpreting the return values and travel time. The microscopic air pockets between the pages provide boundaries for differentiation. [Heshmat] and the team rely on these pockets to reflect the signal back to a sensor in the camera. Once they have the system dialed in to be able to see the letters on the target page and distinguish them from the shadows of the letters on the other pages, they use an algorithm to determine the letters. [Heshmat] says the algorithm is so good that it can get through most CAPTCHAs.

The most immediate application for this technology is reading antique books and other printed materials that are far too fragile to be handled, potentially opening up worlds of knowledge that are hidden within disintegrating documents. For a better look at the outsides of things, there is Reflectance Transformation Imaging.

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Optimizing the Spread: More Spreadsheet Circuit Design Tricks

Last time I showed you how to set up a reasonably complex design in a spreadsheet: a common emitter bipolar transistor amplifier. Having the design in a spreadsheet makes it easy to do “what if” scenarios and see the effects on the design almost immediately.

Another advantage that spreadsheets offer is a way to “solve” or optimize equations. That can be very useful once you have your model. For Excel, you need to install the Solver add-in (go to the Excel Options dialog, select Manage Add-Ins, and select the Solver Add-In). You might also enjoy OpenSolver. You can even get that for Google Sheets (although it currently lacks a non-linear solver which makes it less useful for what we need).

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Hacking a Dollar Store Bluetooth Device

Hardware hackers are always looking for devices to tear apart and scavenge from. It’s hardly a secret that purchasing components individually is significantly more expensive than the minuscule cost per unit that goes along with mass manufacturing. Bluetooth devices are no exception. Sure, they’re not exactly a luxury purchase anymore, but they’re still not dirt cheap either.

Luckily for [Troy Denton], it seems dollar stores have started carrying a Bluetooth camera shutter for just a few dollars (it was three bucks, perhaps the dollar store actually means divisible-by). The device is designed to pair with a smart phone, and has two buttons allowing you to control the camera from afar. The fact that it works at all at that price is a small miracle, but the device also has potential for hacking that adds to its appeal. Continue reading “Hacking a Dollar Store Bluetooth Device”