News of The Wolf

Random, hopefully interesting technical ramblings

Archive for the ‘Electronics’ Category

Twitter Popularity Meter – Hardware

Posted by chemicaloliver on 07/10/2009

The hardware for the system discussed in my previous post consists of an arduino, arduino ethernet shield, 2x 595 shift registers and one 8×8 common anode LED Matrix from china via ebay. Basically the arduino requests the page containing the current popularity metric and then adds it to an array containing the states of the currently lit LEDs which is then pumped out to the shift registers to update the display. The circuit lights the correct LEDs.

The circuit design is based on a design featured on the arduino playground for lighting 8 LEDs but was slight adapted to deal with the matrix.
schematic

I have also attempted to form this into a new arduino shield so I can reuse the LED matrix circuit quickly for other projects, a PCB is currently with BatchPCB

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Twitter Popularity Meter – Code

Posted by chemicaloliver on 06/10/2009

Recently I’ve been working on a popularity meter which searches twitter and displays a bar graph of the popularity of the search term on an LED Matrix driven by an Arduino. It currently relies on a PHP script on my webserver to do the actual twitter search and the arduino reads the page via ethernet and then displays the number on it bar graph.

Arduino Twitter Meter

Arduino Twitter Meter


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Fritzing! (A new electronics CAD Program)

Posted by chemicaloliver on 20/05/2009

While I’ve been experimenting with circuits and ardunio stuff recently I’ve been looking for a simple solution for converting a schematic to a breadboard/stripboard design, I’ve explored a few options like stripboard magic and eagle and non seem to be ideal however today I came across a new project via twitter.

Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to take the step from physical prototyping to actual product”

Available here

It allows the user to create circuits in a simple drag and drop environment on a 3D breadboard complete with arduino template, it can then convert this design into a schematic or etchable pcb and vice versa. It is still very much in development but from my initial playing looks like a very promising project.

fritzing-breadboard

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My First Synthesizer

Posted by chemicaloliver on 14/05/2009

Today I started the first stage in what may become online collaborative synth music performance system, I built a very basic synthesizer.

My design is based on one kindly posted on hackaday which I built on stripboard (very badly). It produces a simple square wave using a hex inverter IC and a capacitor and resistor, the hackaday article also details how to build in an LFO and other bits and pieces however I’ve saved for the next version which intend to package in a nice box al la amazing rolo.

I have often noted people having difficultly locating reasonably priced parts for this type of project online, all parts for this project were sourced in the UK from http://www.bitsbox.co.uk who I found to provide exemplary service for a very good price, especially if you order only a small number of items.

The next version will have more controls and in parallel to this I’ve just received an arduino, this will be used with a digital potentiometer to control the synth parameters in the first instance via a GUI probably written in java or processing and then eventually PHP.

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