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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.

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Published on: September 16, 2013 / Comments: None

LightBox – A Video Jockey oriented RGB LED controller

Bocho came up with a really neat controller for RGB LED strips.  The idea is to compliment a VJ performance, full of knobs and sliders of course.  Something that you can tweak in real time, but can also be assisted by the music.  Bocho started out with this post on bass detection on Arduino, which was then rolled into the controller.

The build uses 3 high power transistors for controlling current, and various pots and sliders that control oscillation speed, luminosity, hue, and selecting manual or beat detection all controlled by an Arduino.  Even better the project is wrapped in a decent looking enclosure.

Source code is available here. Full writeup here on bocho’s blog.  Enjoy a video demonstration after the break. (more…)

Published on: September 15, 2013 / Comments: None

Lazy Sunday Links – 9/15/2013

Sunday is a good lazy day. Time to learn stuff and bang out some easy hacks.

 

Chirp is a Javascript toolkit for creating chiptunes.  Only works in Google Chrome but sounds retro-tastic and actually sounds pretty good.

Voltage dividers are an essential skill to learn when building circuits. Go learn some voltage diviers.

Transmit data serially without a Microcontroller.  Uses a specialized IC by Holtek to transmit and receive, but really quite useful if you have some data you want to move and don’t feel like adding a Microcontroller to your project!

The gMax is a pretty large 3D Printer on kickstarter.  It boasts a 16″ x 16″ x 9″ print volume.  Wow that’s some large prints!

Don’t understand how hobbyist FDM 3D Printers work ?  Here’s a writeup on how they work.

The illustrated guide to crypto hashes.  Informative

Tuning an RTOS can be daunting to pick the right scheduling algorithm. How to select the right algorithm using system modeling.

If you’re not a VIM guru, you’re probably using the nano text editor.  Here’s some tips to make your nano experience a little more pleasurable.  Works on the Raspberry Pi too.

 

Published on: September 11, 2013 / Comments: 2

Mico – a different way of talking to Arduino from your phone

micotechMico is an Arduino shield that talks to your cell phone.  Literally.  It connects via the audio jack on your cell phone, and has the ability to read DTMF tones for control.  It also can answer the phone by using the same technique your old wired headset does.

Some of the applications the mico guys have put together are it answering the phone and reading out sensor data.  It has a audio playback library so with some crafty recordings you can do cool things.  They even have a demo application of the shield talking to Siri on IOS in order to do more functions like send text messages.

Interesting concept, I think it’s still missing something like a little more control but I give them props for being different.

The project currently has a kickstarter going to launch a large production run, there’s also source over at github.