Wednesday, 25 September 2013


We have a problem: We're addicted to cheap fossil-derived energy. Unfortunately the amount of fossil fuel use since the industrial revolution has significantly increased atmospheric carbon dioxide.

"If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm."
 --  James Hansen, NASA

The fossil fuel industry has proven reserves of gas coal and oil five-times what is safe to burn, but they still get tax breaks (AKA subsidies) in exploration efforts looking for more. I'm sure many of their other tax breaks have little to commend them and ought to be culled as well.

On top of the tax breaks, the fossil fuel industry gets to pollute without paying. All other companies and individuals have to safely deal with their hazardous by-products, from chemical waste to littering on the street.

Due to it's role in climate change, carbon dioxide is one of the most dangerous pollutants - but the industry is free to release it straight into the atmosphere, with deadly consequences rapidly approaching.

We need to push all governments to enact carbon taxes which make what is currently an external cost - destruction of the environment - into an internal one for these companies. France's carbon tax announcement looks to be the correct approach, with the revenue to be used in further reducing emissions.

When the alternative is severe damage to every aspect of human life (and if we really do nothing - the end of civilization), an increase in current energy cost is not a valid reason to stick with the status quo.

Naturally there is another component - consumer behaviour. We need to:
  • Reduce our energy (and other resource) usage
  • Choose zero/low carbon energy sources and resources
  • Pressure financial and other businesses to divest fossil fuel investments
  • Pressure government to enact carbon taxes and invest in zero/low alternatives
There's a lot of work to do but, if we decide to act, we can do it.

Saturday, 16 February 2013

A bit of woodwork

My ~10 year old CRT TV died, so I caved and bought a LCD TV to replace it. Pleasingly, this let me put the new TV on the wall, removing clutter from my lounge, and prompted me to get a piece of furniture for the gap between the sofa and the wall.

Unable to find anything with the right dimensions and an acceptable configuration of drawers and shelves, I decided to make my own, as follows...

Total time from concept to completion: One month.

Which is nice.

Wednesday, 4 April 2012

Light Canvas - LEDs 6: Dim power

The previous post demo-ed all the LEDs roughly in place in the frame, running on the dimmer circuit - but not running bright enough. I've figured out (I think) the LEDs aren't getting enough power. Firstly I wanted to establish what is happening in the circuit:

  • From it's specifications, the 2N222A transistor has a beta value of about 100
  • The current applied to the transistor base (555 chip output current) measured at: 1.16mA
  • Taking the above, 100*1.16mA = 0.116A
  • This calculation is confirmed by the measured of current going through LEDs (via the transistor): 0.1A
  • This 0.1A is a quarter of the current needed to fully light the LEDs - measuring the current when driving the LEDs directly from the power supply gave a reading of 0.39A (pretty close to the calculated value of 0.42A)
  • The transistor's peak base current is 200mA, so the max emitter current (base current * beta value) should be 200ma*100 = 20A - considerably more than the 0.4A needed.
  • It should be possible to get the 0.4A - I just need to figure out how to get more current into the base.
Answers on a postcard...

Sunday, 4 March 2012

Light Canvas - LEDs 5: All the LEDs

Here are all the LEDs running - 12 panels, each with 5 LEDs. They're not fixed in place yet, just taped in the approximate location.

It turns out that the 555 dimmer circuit isn't quite right, as it seems that the LEDs aren't getting a large enough current - 0.16A, rather than 0.45A (when powering all the LEDs without the dimmer).

I guess it's something due to the transistor not putting/allowing enough current through...


Monday, 27 February 2012

Light Canvas - LEDs 4: Progress!

Having important things to do can be really motivating - for other projects. I've household repairs to organise, but can't figure out an elegant way for it to be done - so I'm ignoring that for the moment, and have made some progress on the Light Canvas :-)

Subsequent to my last post on this project, I satisfied myself that the circuit was ok, and ordered a bunch of components, and took the opportunity of a OxHack session to  breadboard the control circuit, which I did - except for the minor point that the circuit didn't actually work... Oh well, it was a nice event, and good to meet some more hackers and see what they were up to - I need to get along to more of that sort of thing!

Many months later, I've a working breadboard with the 555 astable circuit producing a pulse width modulation varied from 0-100% depending on a potentiometer. The 555 PWM doesn't have enough power to drive the LEDs directly, so it's used to control a transistor which effectively amplifies the power of the PWM enough for the LEDs. W00t!

This happened by:
  1. Getting the 555 PWM working on a single LED directly,
  2. then on a panel of 5 (on a breadboard) via the transistor, then (the next day),
  3. making up 9 perfboard versions of the LED panel, powered via the LED.

Video evidence:

Next steps;
  1. Convert the 555 circuit from breadboard to perfboard.
  2. Modify the frame to house the circuit, controls, and wiring.
  3. Modify the frame so the back can be attached, and hung on the wall.
  4. Stretch the canvas onto the frame.
  5. Install the electronics in the frame, and put it all together.
  6. Put on wall and bask in its glow :-)

Thursday, 24 November 2011

I really ought to...

I really ought to pimp Listing Ships a bit more, especially the EP we're putting out in a couple of weeks. I done a video for it and everything, innit. We've got a gig on Dec 9th as well...

Friday, 16 September 2011

For the record...

The Ribbon interface in MS Office pisses me off.