Choose the duty-cycle with care. The duty-cycle is the percentage of time a device is on, compared to the total time. It is normally defined by the number of times we want to read sensors each hour. Most of the projects can have their Waspmotes sleeping most of the time. For example, there is no reason to measure temperature every 1 minute: it just does not change in such a quick way! Depending on the parameters you want to control, you will have different duty cycles. Most of our clients measure each 5-10 minutes, which means sleep times of 5-10 minutes and loops of few seconds.