A very tiny gamma ray detector


When you think of a radiation detector, you’re probably thinking of a Geiger tube and its high voltage circuitry. That isn’t the only way to measure gamma radiation, though, and [Alan] has a great circuit to measure even relatively weak radiation sources. It uses a very small photodiode, and draws so little power it’s perfect for projects with the smallest power budgets.

The detector circuit uses a miniature solar cell and a JFET wired up in a small brass tube to block most of the light and to offer some EM shielding. This, in turn, is attached to a small amplifier circuit with a LED, Piezo clicker, and in [Alan]‘s case a small counter module. The photodiode is actually sensitive enough to detect the small amounts of gamma radiation produced from a smoke alarm americium source, and also registers [Alan]‘s other more powerful radioactive sources.

The circuit only draws about 1mA, but [Alan] says he can probably get that down to a few micoAmps. A perfect radiation sensor for lightweight and low power applications, and gives us the inspiration to put a high altitude balloon project together.

Keurig hack now automatically fills the water reservoir


This hack makes your Keurig experience fully automatic. For those that aren’t familiar with the hardware: this type of coffee maker includes a water reservoir. Coffee is brewed One cup at a time by drawing from that water, quickly heating it, then forcing it through disposable pods containing coffee grounds and a filter. This takes the user-friendly design one step further by automatically keeping the water full.

This goes beyond the last water reservoir hack we saw. That one routed a water line to the machine, but included a manually operated valve. [Eod_punk] added a solenoid valve and level sensor in this project. The level sensor is submerged in the tank and is monitored by a Basic Stamp microcontroller. When the level is low the BS1 drives the solenoid via a transistor, letting the water flow. This is all shown in the video below.

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Quick and dirty touch-sensitive keyboard project


You don’t have to have high-quality parts to play around with electronics and here’s a great example. [Vishal] used junk to play around with CapSense, the touch sensitive Arduino library. What he ended up with is this touch-based piano keyboard.

We’ve featured the CapSense library in the past, but even that example uses a very meticulously crafted test rig of foil tape, protoboard, and some resistors. If you still haven’t given it a try follow this example of using aluminum foil, electrical tape, and a cardboard box.

[Vishal] just sandwiched the end of jumper wire between two pieces of foil to make each ‘key’. We believe the other end of the wire is soldered to the bias resistors where they connect to a couple of pin headers. The headers were hot-glued in place through holes in the bottom of the box, making the entire rig simple to plug into the Arduino board driving it. After adding in a small speaker and flashing the code he’s finished. It certainly makes for a short afternoon project which you won’t feel bad about taking apart later since you didn’t sink a ton of time or resources into the build.

The thinnest Xbox laptop yet


With every generation of consoles, there comes a time when the price of a new box is cheap enough, and used machines are plentiful enough, that console hackers pull out all the stops before the next generation arrives. For the Xbox 360, that time is now, and with no PS1-like hardware revision on the horizon, it looks like [jhax01]‘s custom Xbox 360 laptop might be the smallest Xbox casemod we’ll see for a very long time.

[jhax01] was inspired by the work of [Yung Jeezus] and [AllYourXboxNeeds]‘ YouTube channels and decided to craft his own custom enclosure for an Xbox 360 slim. The case was made out of aluminum plate cut with a simple angle grinder and bent on a cheap 18″ Harbor Freight brake. Despite these extremely simple tools, [jhax01] managed to fabricate a case that’s right up there with the masters of Xbox laptop craftsmanship.

The CD drive was ditched along with plans for a second hard drive. The display’s enclosure and hinge comes from an ASUS Zenbook, hence this project’s eponym, the ZenBox. The panel from the display was discarded and replaced with one that would work with the LVDS converter [jhax] found, giving the laptop a resolution of 1366×768.

It’s an amazing piece of craftsmanship, and an impressively thin gaming console to boot. Throw in a battery, and we’d be more than happy to carry this one around with us.

Benchmarking USB transfer speeds


[Paul Stoffregen], creator of the Teensy series of microcontroller dev boards, noticed a lot of project driving huge LED arrays recently and decided to look into how fast microcontroller dev boards can receive data from a computer. More bits per second means more glowey LEDs, of course, so his benchmarking efforts are sure to be a hit with anyone planning some large-scale microcontroller projects.

The microcontrollers [Paul] tested included the Teensy 2.0, Teensy 3.0, the Leonardo and Due Arduinos, and the Fubarino Mini and Leaflabs Maple. These were tested in Linux ( Ubuntu 12.04 live CD ), OSX Lion, and Windows 7, all running on a 2012 MacBook Pro. When not considering the Teensy 2.0 and 3.0, the results of the tests were what you would expect: faster devices were able to receive more bytes per second.  When the Teensys were thrown into the mix, though, the results changed drastically. The Teensy 2.0, with the same microcontroller as the Arduino Leonardo, was able to outperform every board except for the Teensy 3.0.

[Paul] also took the effort to benchmark the different operating systems he used. Bottom line, if you’re transferring a lot of bytes at once, it really doesn’t matter which OS you’re using. For transferring small amounts of data, you may want to go with OS X. Windows is terrible for transferring single bytes; at one byte per transfer, Windows only manages 4kBps. With the same task, Linux and OS X manage about 53 and 860 (!) kBps, respectively.

So there you go. If you’re building a huge LED array, use a Teensy 3.0 with a MacBook. Of course [Paul] made all the code for his benchmarks open source, so feel free to replicate this experiment.

Hardware store robot hand


Here’s a robot hand which can be built using mostly hardware store items. It doesn’t have the strongest of grips, but it does have lifelike movement. The demonstration video shows it picking up small objects like a metal nut.

The image above shows the ring and pinky fingers of the hand beginning to flex. These are controlled by the servo motors mounted in the palm area. The skeletal structure of each digit begins with the links of a bicycle chain. The links are first separated by removing the friction fit rods. Each rod is replaced with a screw and a nut, which also allows the springs (which open the digits) to be anchored at each ‘knuckle’.

[Aaron Thomen] didn’t stop the design process once the hand was finished. He went on to build a controller which lets you pull some rings with your fingers to affect movement. This movement is measured by a set of potentiometers and translated into electrical signals to position the hand’s servo motors. The demo, as well as two how-to videos are embedded below.

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