Designed by Chris “Akiba” Wang of Tokyo Hackerspace and its geiger counter project, Freaklabs’ Freakduino combines an Arduino with a built-in wireless board, giving you the ability to transmit data wirelessly without buying extra components.
I originally designed this circuit a few years back when I was looking for something to do long distance wireless sensor links, on the order of kilometers or tens of kilometers. 2.4 GHz gets a bit hard to drive that far since higher frequencies have more attenuation in free space as well as a difficult time going through objects. Lower frequencies have much less attenuation and are able to travel through obstacles more easily so they’re ideal for situations where range is valued over speed. In sensor networks, data rate usually has a low priority compared to battery life and communications range.
However, he hasn’t just switched up the radio; power management has been improved:
The hardware is optimized for low power operation and in sleep modes, only consumes 300 uA at 3V (2-AA batteries). This would theoretically allow 2 AA batteries to power this device for months with proper power management and low duty cycles. The battery boost circuitry differs from the standard Freakduino series in that it has two separate boost circuits. During transmission, the front end amplifier puts a lot of power into the signal so the boost converters were doubled up to support both the wireless circuitry and still have spare current for other devices attached to the board.
The hidden advantage to the Freakduino is that Akiba makes them compatible with a ruggedized enclosure he sells, making them perfect for outdoor or hazardous conditions. There’s a custom proto board on one end, and they come with a lovely silicone bumper that fits around the plastic box. Finally, Akiba will be selling the boards at a 10% discount for a few days, so shop early!