Turning a phone into a Geiger counter

geiger

We’re no stranger to radiation detector builds, but [Dmytry]‘s MicroGeiger prototype is one of the smallest and most useful we’ve seen.

The idea behind the MicroGeiger comes from the observation that just about every modern smartphone can provide a small bit of power through the microphone jack. Usually this is used for a microphone, but with the right circuit it can be stepped up enough to power a Geiger tube.

[Dmytry]‘s circuit uses a hand-wound transformer but keeps the part count low; there’s only a few dozen caps, resistors, and diodes in this build, making the circuit much smaller than the Geiger tube itself.

Since [Dmytry] is powering a Geiger tube with a phone, it only makes sense that he should also record clicks from the tube with an Android app. Right now, the entire project is still in the prototype stage, but everything works and his app can detect radiation from one of [Dmytry]‘s sources.

The code and schematics for the MicroGeiger are available on GitHub, with a video of the project in action below.

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Wireless rover with Android control

android-rover

[Radu] spend the first portion of this year building and improving upon this wireless rover project. It’s actually the second generation of an autonomous follower project he started a few years back. If you browse through his old postings you’ll find that this version is leaps and bounds ahead of the last.

He purchased the chassis which also came with the gear-head motors and tires. Why reinvent the wheel (har har) when you’ve got bigger things on your plate? To make enough room inside for his own goodies he started out by ditching the control board which came with the Lynxmotion chassis in favor of an AVR ATmega128 development board. He also chose to use his own motor controller board. Next he added a metal bracket system to hold the battery pack. Things start to get pretty crowded in there when he installed his own Bluetooth and GPS modules. Rounding out his hardware additions were a set of five ultrasonic sensors (the grey tubes on top), a character display, as well as head and tail lights. The demo video shows off the control app he uses. We like that tic-tac-toe design for motion control, and that he added in buttons to control the lights.

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ODB-II hacking using an Android tablet

odb-II-hacking-eagle-grand-cherokee

What a strange message to read on the digital dashboard display of your car. This is proof that [Kristoffer Smith] was able to control the ODB-II bus on his Eagle Grand Cherokee.

He’s not just doing this for the heck of it. It stems from his goal of adding an Android tablet on the dashboard which has been a popular hack as of late. This left [Kristoffer] with steering wheel controls that did nothing. They originally operated the radio, so he set out to make them control the tablet.

He had seen an Arduino used to control the CAN bus, but decided to go a different route. He grabbed a USB CAN bus interface for around $25. The first order of business was to use it with his computer to sniff the data available. From there he was able to decode the traffic and figure out the commands he needed to monitor. The last piece of the puzzle was to write his own Android code to watch for and react to the steering wheel buttons. You can check out the code at his repository and see the demo after the break.

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Semi-automatic pick and place machine

semi-automatic-pick-and-place

This is a fascinating take on building your own pick and place machine. It does an amazing job of automating the hardest parts of hand assembly, while relying on human dexterity to achieve the hardest parts of automation. It’s a semiautomatic pick and place machine driven by an Arduino and controlled by an Android tablet.

The machine is built in two parts. The portion in the upper left feeds components from reels and is fully automated. The portion on the lower right consists of a padded arm-rest which slides smoothly along two axes. A mechanical arm with multiple articulations is attached to the end, culminating in a tip connector for some vacuum tweezers. Right handers are the only ones who will find this convenient, but oh well. The clip after the break shows it in action. The assembly technician first selects the component from an icon on the Android tablet. The reel machine then dispenses that part, which is picked up by the vacuum tweezers using the left hand to switch the vacuum on and off again. If the part orientation needs to be rotated it can done using the jog wheel on the Android app. It smooth, quick, and best of all, clever!

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Guitar EQ levels trigger the stage lights

guitar-eq-strobe-control

Even if your band hasn’t made it big yet it’s still a lot of fun to put on a great show. This hack will help you add lighting effects to performances without having to shell out for a lighting technician. [Phil] put together a hack that lets you trigger the lights by setting a volume threshold with a pedal switch.

After reading about the hack that adds an EQ display for a pedal board he got the idea to convert the concept as control hardware instead of just for feedback. Just like the visualization project he uses an MSGEQ7 chip which takes care of the audio analysis. He’s using this for electric guitar so he only monitors three or four of the outputs using an Arduino. He built the hardware into a foot pedal by mounting a momentary push button on the lid of the enclosure. Stepping on the button causes the Arduino to save the the current audio level. Whenever it reaches that threshold again it will switch on a mains relay to drive an outlet. In this case a strobe light turns on when he starts to rock out, which explains the bizarre image above. You can get a better feel for the theatrics by watching the clip after the break.

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Wireless Temperature Control for a Microbrewery

Wireless Temperature Control

When brewing your own beer, temperature control is important. If the temperature isn’t regulated correctly, the yeast will be killed when it’s added to the wort. It’s best to cool the wort from boiling down to about 25 C quickly before adding yeast.

To do this, [Kalle] came up with a wireless temperature controller for his home brewing setup. The device uses a heat exchanger to cool the wort. An ATmega88 connected to a H-bridge controls a valve that regulates flow through the heat exchanger. It reads the current temperature from a LM35 temperature sensor and actuates the valve to bring the wort to a set point.

A neat addition to the build is a wireless radio. The nRF24L01 module provides a wireless link to a computer. There’s an Android application which communicates with the computer, providing monitoring of the temperatures and control over the set point from anywhere [Kalle] can get an internet connection.

Android controlled Minecraft ores

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[Ryan] has a friend with a birthday coming up, and being inspired by ever 12-year-olds favorite game, he decided to make a Minecraft ore block with RGB LEDs. The block can change from diamonds to emeralds via commands send from an Android phone.

After a few false starts, [Ryan] eventually had his ore cube laser cut at Acess Space, a hackerspace-ish group in Sheffield. The box was constructed out of 3mm MDF, while the windows were laser cut out of frosted acrylic, while the stone pattern on the cube is one giant custom-made sticker.

With the tedious part of the build out of the way, [Ryan] set to work on the electronics. He used a PIC attached to a few very large RGB LEDs, and a Bluetooth module that allows him to connect his phone to an ore block. Dialing in the right colors took some work, but eventually, [Ryan] had an Android-controlled Minecraft ore block, able to transmutate between gold, iron, diamond, emerald, lapis, and redstone.

You can check out a video of [Ryan]‘s ore block in action after the break.

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