News of The Wolf

Random, hopefully interesting technical ramblings

New Blog

Posted by chemicaloliver on 15/11/2009

Recently I’ve moved on from the restrictions of having a wordpress blog and now I’ve moved all content to chemicaloliver.net

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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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Powershell and arduino serial communication

Posted by chemicaloliver on 25/09/2009

After struggling to get a bash script to send data from curl correctly to my arduino over serial I resorted to windows and found that communication over serial can be quickly achieved using the Powershell (the new cmd). I naively assumed it would be easier in linux than windows however the Powershell does seem to be quite a match for bash. I achieved what had taken me hours in Linux in about 10 minutes. The following example code shows the connection to the arduino and how to send data to any serial device This can of course be formed into a more sophisticated script or just run line by line:


$port= new-Object System.IO.Ports.SerialPort COM3,9600,None,8,one #opens serial port - adjust parameters accordingly
$port.open() #opens serial connection
$port.Write("Hello World") #writes your content to the serial connection
$port.Close() #closes serial connection

If you are not sure of the name of your serial ports then you can list them in the powershell:

[System.IO.Ports.SerialPort]::getportnames()

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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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Writing a GUI in Processing

Posted by chemicaloliver on 15/05/2009

When I first started looking into the Processing language it is quickly apparent that out of the box there is very little in the way of handling user input by way of GUIs. This has been rectified in a very nice way by the team who developed controlP5 this is in my opinion the easiest GUI library I’ve ever used enabling me to create sliders and knobs in a matter of minutes, having programmed very little in processing before. What I came up with is the start of the interface for my planned ardunio controlled synth system:

My controlP5 GUI example

My controlP5 GUI example

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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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Choosing a host…

Posted by chemicaloliver on 13/05/2009

So I decided I wanted to start a blog, I have a few interesting projects I believe other people in the community would be interested in reading about as I read many blogs of similar projects everyday and am inspired by new ideas presented by normal people. However that raises the question of how best to do it?

Being an ambitious currently unemployed  Computer Science graduate I felt I wanted somewhere to showcase my skills, instantly a paid for hosted site seemed like the obvious option. After many hours of research I came the conclusion it was too difficult to sift through to find the most reliable company, all cheap options seemed to have a large selection of terrible reviews except more expensive companies and the free ones like wordpress and blogger. WordPress and blogger and other similar systems don’t have the same vulnerabilities as shared hosting and I’m not paying for the privilege of being annoyed by bad service which seems ideal. When  decide I something worthy to show using a paid for site I will pay a bit more and have a decent service but for now viva la free blogs!

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