Tuesday, 30 September 2008

Phone battery



This remains one of my favourite hacks. It's really simple: find out what voltage is needed and then work out how many AAs are needed to make it up. The battery for my phone is rated at 3.6v, so 3 1.2v rechargable AAs was close enough. After that, the choice of battery comes down to how long you want the phone to last. My original battery was 700 mAh, so 2000 mAh batteries wired in series gives almost 3 times the battery life.
If the battery isn't labeled, use a multimeter to find the positive and negative terminals (usually on the outside). Don't just accept the first reading since the charging terminals can output current on some batteries. The ones you want will generally be the highest voltage. Note that a fully charged battery will usually give abit more than its rating. eg a 1.2v rechargeable AA will give 1.5v and a 1.5v volt alkaline will normally give 1.7-2v.

Wiring is simple. Connect the positive and negative terminals of the phone to the positive and negative terminals on the battery holder. When I did mine, I didn't do anything with the charging terminals. This meant that I had no battery life indicator. On phones where this is the case, you might be able to get it to work by putting a resister in the right place, but I don't know. I haven't tried.



Saturday, 12 April 2008

Grouphug - Clustering with an evil twist!

Of all the things that are likely to be on this blog over the next while, this represents by far the largest amount of time and effort. I've spent time on it every day on the tube to and from work for several months, and lots of my spare time. And yet... I have very little to write about it without going into excruciating detail that would bore most readers. If you are interested in that detail, I recommend first taking a look at how it works, then viewing the integrated help since the documentation is quite thorough. So what have I spent so much time on? A clustering frame work...... written in bash!

While its still got a long way to go, I've just released the first publicly available version. This version lays the foundations and is intended as a proof of concept to show that all the parts can work together.... and that they can work at all! ;) Over the next couple of months, I plan to release a number of subsequent versions that will do master and worker node fail over, monitoring and much more.

But in the mean time, take a look around.