Using Systm episode 57 from Revision 3 as inspiration, I wanted to build an inexpensive portable power source for my Canon A590IS. I use this point-and-shoot camera for timelapse projects as it’s one of the many Canon cameras which can run the alternate firmware CHDK. The Canon Hacker Development Kit opens up loads of cheap cameras to a whole new world of possibilities, one of them being timed scripting; check out the CHDK Wiki for more information.

The video you can see to the right of this article was taken using the cameras’ only portable power sources which comes in the form of 2 AA batteries. The video is short because (in the cold) the camera only made it to 340 shots before expiring its full charge. I needed something portable, but with a lot more power. USB power was ruled out as my model of camera doesn’t support it, even so, USB battery solutions are often low capacity and comparatively expensive. The final solution is based around a 12V 12Ah lead-acid battery, and while lead-acid is very old (heavy!) technology – it is cheap. Here’s my solution based off the power pack devised by Systm, using parts available in the UK.

• 12V 12Ah Sealed (Rechargeable) Lead Acid Battery ~£30 from eBay
• 12V DC Car Power Accessory Outlet £3 from eBay
• Universal 3A DC Power Supply £10 from Maplin
• Cramp-on quick connects £0 from Dad’s shed

Granted it’s not the prettiest looking external power solution on the market, but it is one the cheapest by capacity. Most small consumer electronics can be powered from a 12V source; the important bit to work out in advance is the Voltage and Amperage your device is expecting. In my case the Canon A590IS needs 3V at ~3A, this prompted me to go with the 3A car converter as it also allows for 1.5, 4.5, 5, 6, 9 & 12V outputs (all at 3A) and came with a load of suitable connectors – one of which fitted my camera.

Overall I am very pleased with the end result. I chose to splash out on a Loewpro Apex 110 AW to finish the project as it fits the battery dimensions perfectly and offers rain protection. I’ll report back on overall performance in a post shortly but I expect to get ~6-8k shots using this solution.

Spotify is an application for Windows and Mac which allows you to stream the back catalogues of some of the biggest music labels including Universal, Sony BMG and EMI.  The application is free and music streams instantly, so what’s the catch? Well, if you’re not willing to pay £9.99 per month for the service you will hear a few adverts (I would say around one, 30sec ad per 6 to 10 tracks) but this is certainly no major inconvenience. You can also create and share playlists with other Spotify users which is great for keeping a track of the great stuff you will no-doubt hear along the way.

To sign up for a Spotify account without waiting for an invitation, check out this direct link https://www.spotify.com/en/get-started

One you have signed up, download the desktop client (Windows or Mac) fill in your account details and you’re off! Spotify is partially P2P, meaning that some of the music you will be hearing is being played out of the cache of somebody else’s Spotify player. This also means that you will sharing the music you have played (and cached) with others. To limit this I would recommend setting the cache limit to ‘use at most’ 1GB, otherwise it defaults to 10% of your hard drive. Make sure you close the application fully as well, as it often lurks away in the notification area (in Windows) after you click the cross to close.