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Published on: October 9, 2013 / Comments: None

Spooky Halloween effects door using Raspberry Pi

Who doesn’t love Halloween?  Especially since most of us are on the other end now doing the scaring instead of being a scared kid snatching up candy.  Cabe wanted to create some pro haunted effects for himself and came up with a pretty cool project.

The build uses a 24″ LCD screen that is supposed to look like a window.  Behind the door are a bunch of solenoid’s controlling pneumatic piston’s that really bring the video to life, making you think something is on the other side trying to get out.  Everything is controlled by a Raspberry Pi, and it is triggered by a photoelectric beam sensor.  The code is written in good ol’ regular c and the video is played through OMXPlayer.

Check out the video demo after the break.  Source code, schematics, BOM and other details can be found on element14.


Published on: October 3, 2013 / Comments: 2

Use the web to control an HDMI Switcher

Universal remote controls are a natural want.  I know I hate having 100 remotes for everything remote control.  So what do you do when you start getting used to using your phone as a remote (via web interfaces) ?  Well start converting your other stuff to be controlled via the web too!

Dalgibbard has an entertainment center using XBMC and a Raspberry Pi.  But the HDMI switcher uses an infra-red remote control.  So naturally Dalgibbard hacked the switcher to be controlled by a web interface on the Raspberry Pi.

The HDMI switcher is wired up to the Raspberry Pi via a relay and a few discrete components to the GPIO pins.  The pins are controlled by a python script that is executed by a web page using PHP and Apache.  Simple and efficient.

More pictures, schematic, source here.

Published on: October 2, 2013 / Comments: 3

DIY Watch uses OLED screen and ATMega328

With the advances of shrinking technology it’s becoming more and more easier to roll your own every day items.  Ever thought of making your own watch ?  Sure you have, it was probably going to turn out larger than you anticipated too huh?   How’s 1.5mm thick sound ?   Sounds pretty good to me too.  Zak has a really awesome writeup of him rolling his own watch.

The display is a 0.96″ OLED display (128×64 pixels), it uses a DS3231M RTC, 2 LEDs, a buzzer, a 3 way switch and runs off of a 150mah LiPo battery.   Impressive!  Features of the software include, window animations, up to 10 alarms, games, stopwatch, and flashlight mode.

Power consumption numbers are decent too.  6ua in sleep mode, and 10ma with normal on.  That means depending on how much time you spend with the screen on will dictate how long your charge will last.  This puts you anywhere between 15 hours and 3 years.  With those sort of numbers and a modest use of your watch you should be able to get 15-30 days out of a single charge.

The Schematic and source code are available on Zak’s web site, a long with more photos of the build.  Enjoy a video and a few more pics after the break.


Published on: September 26, 2013 / Comments: None

Building a noise generator with transistors

Believe it or not, it’s actually quite difficult to generate random numbers on computers and microcontrollers.  I’m talking about true random.  A lot of the randomness computers use isn’t random at all, it’s predictive (or pseudo random).  Difficult, but still predictive.   It’s important when doing cryptographic functions to use a good random source.

So f4grx decided to build a random circuit and do some analysis on it.  The circuit design is built around the idea of using an open collector on a transistor.  What’s essentially going to happen is tiny electrical noise in the air is going to cause the circuit to produce 1′s and 0′s which then can be used to plot random.

Interesting read.  Check out f4grx’s experience.

Published on: September 22, 2013 / Comments: None

Attiny 2313 V-USB Media Volume Control

I know this awesome project is a few weeks old but I’m going to use the fact that Rupert recently posted an update as my excuse to share it on hackalizer. As the title implies the V-USB Media Volume Control project is using V-USB. V-USB is software which makes it possible to add low-speed USB to almost any AVR microcontroller without any additional hardware.

Inside Volume Control EnclosureFrom selecting the perfect rotary encoder to designing and etching his own PCB and eventually making a custom enclosure, this project shows is all. Rupert explains some of the minor but important differences of the rotary encoder such as the number of detents and amount of force required to turn the knob and press the button.  He also shares an important lesson on load capacitance with regards to the crystal on his home-brew board. Check out the build video after the break.


Published on: September 20, 2013 / Comments: 1

Remote control aquarium lighting with Raspberry Pi and Node.js

Bryan bought a new aquarium awhile back and some pretty little fish to go with it.  The tank’s lighting system has a day and night mode in order to be a little more realistic for the fish’s natural environment, but you have to physically switch it between day and night.  So as any hacker would do, he hooked a Raspberry Pi up to it and made it remote control!

The hardware control interface is a transistor and a relay connected to the gpio of the Raspberry Pi.  The software interface has a manual mode and automatic mode.  In automatic mode it pulls the sunrise and sunset data from the interwebs and alters the day/night modes accordingly.

Aside from the original article, Bryan decided to go a little deeper on the build with an overview in part 1 and hardware rundown in part 2 where he has the schematic and his pcb layout.

Source code is available on github.  Info on getting node.js up is on the original article. Video demo after the break;


Published on: September 18, 2013 / Comments: None

LED Fireflies are the new LED Throwie

Admit it, you still love LED throwies, everyone does!  So does David.  After viewing an article on very low power LED fireflies by Karl Lunt, David decided to build the project (and does a good job of documenting the process to reproduce it).  The LED fireflies use the LED as a photosensor to detect when there is light so it knows when to go to sleep, thus by saving power by not doing anything with the lights on.

The build works off of a CR2032 coin cell battery, and everything is dead-bug soldered together.  The microcontroller is an ATTiny13a which is already a low power microcontroller, but by using the LED as a light sensor periodically, the microcontroller knows when to sleep and doesn’t wake up until the light level changes below a threshold.  This allows the firefly to last a really long time on that single coin cell.

David added a little spin on the original by wrapping it in a waterproof enclosure (à la sauce container) and a magnet (so it can be a throwie).  This looks like a fun build.

Source code can be found on Karl’s site.  David’s writeup can be found here.  Video after the break.