The Raspberry Pi organisation has launched a new board. This is the Raspberry Pi Zero, an upgrade/replacement for the Model A board.
The most significant change is the price, $5 or £4, so the cost has dropped substantially. But so has the size. At just over half the depth of the original Model A, the Zero means that you can now place the power of a Raspberry Pi in even smaller things.
The Zero has a faster chip, moving the clock speed from 700Mhz to 1Ghz, has double the memory (512MB rather than 256MB). Storage is via a micro-SD card. It has moved to smaller connectors (both mini-HDMI for video and micro-USB for power and connectivity). It uses the same 40-pin GPIO header as the Model A/B+, so will take all the various HATs for these. But to squeeze everything in, something has had to go, and that is the camera connector.
Power consumption has dropped on idle to 0.5W, so it is more battery friendly. Active power consumption is the same as the Model A, at 1.75W.
The board uses the same processor as the Model A (and original Pi Model B), so take the card from your existing Model A+ or Model B+, and boot up the new device.