Well what can I say; Its been a productive day.

Today Mike and myself set out to create our experimental guitar signal meter.
The day was off to a little bit of a rocky start for a few reasons;
After lugging all the kit – 2 laptops, one guitar + cables, tools, breadboard and electronics and donor material (Marshall amp)
I realised I’d forgotten our multimeter – So theres one trip home.
After returning I thought I’d tune the guitar – and promptly snapped the ‘b’ string. Great
And to top it all off I couldnt source a MOSFET transistor.

But nevermind; we got off to a flying start – Mike researched use of our transistor for amplification while I popped off and unsoldered the Mono Jack we needed to use to accept the guitar input.
After having this we rechecked the polarity of the signal coming in to the Jack using the multimeter so wires could be soldered and plugged into the appropriate spots on the breadboard.

At this point our circuit looked like this:

Now although I predicted that the output signal of the guitar alone would be too weak for the stamp to measure we used the programmers debug command to watch the readings in real time; which yielded some suprising results:

The debug console was showing readable results (although very low) – but still; these readings will do just fine for todays experiment – so we done what any other self respecting designer would do – made a light flash…Just because we could. This concerned programming a simple “If” statement into the stamp – basically saying that if the stamp read anything over a background noise level – to light the Red LED. The results? We’ve got a video for that too!

Now that we are confident we could turn an analog input into a digital output – we set to split the signal into three ranges. Unfortunetly because of the weakness of the signal the ranges would be relatively small and innacurate – but there was a definate proof in the code.

In the end the code that we had looked a little (well, exactly) like this:

So – There you have it – another successful venture.
Next we will be hunting down and capturing a MOSFET transistor – and amplifying the signal to get a more useful, accurate range out of the signal – then doing something fun with it!

Stay classy internet
– Allan and Mike


Today I have spent a short amount of time “Device Hacking” Using my Marshall portable double stack amp to conduct some experiments. This is our “test subject” .

Our unsuspecting test subject

After slightly dismanteling the amp to get in at her goodies I was able to start measuring what sort of signal inputs it received from guitars and various audio devices (This will become vital in later work). Firstly measured at the Audio in Jack (without any amplification) I found out that the device was outputting around 100 milivolts upwards (to about 600 milivolts) depending on what was being played on the guitar.

Starting to get interesting...
This also told me that as the “Volume” of the playing increased – as did the voltage of the signal – Although this is acctually very hard to tell using a digital mulitmeter. So to test this theory and to build upon our last sort of basic LED circuit – I have began thinking about building a digital LED Signal Volume meter (this will also allow further itteration into a more complete product).

However I am doubtful that the basic stamp can quantify such low input voltage – So I measured what the post amped signal was inside the Marshall – On average between 0v-6v but sometimes beyond – far too high for the stamp.

This gives two options

  • Further dismantle my precious marshall amp and retrieve the delicious amplifier circuitry¬† and then provide it with the stamps 5v power supply to give it a more reasonable input


  • Design a simple transistor circuit and variable potentiometer to acheive the signal strength needed (and range)

So far I have designed a circuit for the latter as I love my amp too much to harm it further. A basic outline of the circuit and coding is pictured below

Potential Electrocution

And what documentation would be complete without showing the other tool I am using?

The woman in my life
Stay tuned to see the finished volume meter
– Allan


Kellogs Crunchy Code

Posted: February 2, 2011 in Uncategorized

Evening all!

Its been an exciting week so far; Taking part in psychological experiments, being a guest on the Pip Carters show, and working PR with my two colleagues (Mike Skillings and David Fisher)
But probably most exciting of all was Tuesdays experimentation class, myself and Mike came up with something tangible by the end of the day. The new program we are using to program the universities new Stamp chips is based on but not a complete replica of the basic language – So is taking some getting to grips with again.

The new stamp chips are particularly interesting because the chip has integrated many features that would usually require additional peripherals such as the ADC (Analog to Digital Converter).

By the end of the day myself and Michael managed to construct the circuit (after some rather fantastic soldering on my part) and code a basic program that would switch on one of two LED’s depending on the value of the attached potentiometer.

Heres a video of the program in action:

Stay tuned for more wacky experiments!
– Allan

Music To Your Ears

Posted: February 1, 2011 in Uncategorized

Hi All.

I’ve put together a quick demo video to illustrate our general idea/direction of the project.

Please excuse the guitar playing!

– Enjoy

Moods for music.

Posted: January 21, 2011 in Uncategorized

Myself and my co-designer for this project (Mike Skillings), have discussed the idea in a little further depth. Like me, Mike is also a guitarist and we are both interested to look into how light can reflect what is being played.

We have both managed to separately come up with the idea of assessing and conveying the mood of what is being played by the instrument through the medium of light. This would consist of intensity, colour, pulsing etc.

For example: A slow glowing blue hue for an acoustic piece, and a fast pulsing red glow for Metal music.

But is there a way of being able to differentiate between each of these?
Expect to be seeing some research and perhaps a few thoughts from Mike soon.

Maybe both idea’s/concepts can be combined?

– Allan

A new direction

Posted: January 19, 2011 in Uncategorized

Im currently thinking along the lines of making some sort of visual representation of music.
Since guitar is something that I attempt to play every now and then – Im choosing this as a medium (for now).

The idea consists of this:
The player plays a guitar (or does something that resembles playing)
The notes are then displayed – in some way, shape or form.
In a way that the patterns or ‘moods’ can be obeserved.

Next steps should be :

  • Checking the viability of the product
  • Researching how to measure the input (notes played)
  • Pondering final output.

Stay Tuned! (get it?)
– Allan