An even cheaper Raspberry Pi has gone on sale in Europe with less stuff on it so the tiny ARM-compatible Brit-puter can consume even less power.

The Model A Pi was touted during the hype-gasm surrounding the Raspberry Pi's launch in February last year. But it was the Model B circuit board that went on sale first, and went on to sell a million units to date, whereas the A-series is now available.

The A-series Pi is aimed at folks who want to run projects from battery or solar power, such as robots or sensors in remote locations. Not content with how little juice the wee machine draws now - it is in the order of milliamps - the foundation will be working on getting the consumption down even further.

"We are very, very pleased to finally be able to offer you a computer for $25. It’s what we said we’d do all along, and we can’t wait to see what you do with it," said the charity's Liz Upton.

The names Model A and B are a homage to the Acorn BBC Micro Model A and B: the Pi's designers hope their cheap credit-card-sized machine will encourage people, especially children, to take an interest in computer science just like the Beeb did in the 1980s. The BBC Micro was also conceived in the shadow of Cambridge University just like the Pi, which uses an ARM processor core that's a descendant of the RISC architecture designed by Acorn boffins in Camby during the mid-1980s. It's a rather circular pie. ®