We have designed an ultra-low power sensor networking platformcalled the i-Bean Network. The i-Bean Network requires a reliable RNG (Random Number Generator) for various purposes such as random backoffs, random transmission delays and random packet sequence numbers.
We could not use the existing RNGs because they require special purpose hardware and/or involve complex computations. We have designed a simple PRNG based on a free-running timer. Although this PRNG was specifically designed for the i-Bean Network, it could be used in other low-power embedded networks.