A previous post described Vipul’s initial experiment on collecting data from a solar-powered Sun SPOT. That experiment helped uncover and fix several bugs that caused disruptions in data collection. He repeated the experiment again last month using the red-090113 release of the Sun SPOT SDK to test those fixes.
This time around, the SPOT stayed off the power grid from Feb 12 until Mar 3 — slightly over 19 days (that’s more than 1.6 million seconds) — reporting light, temperature and other readings every 10 minutes. Unlike last time, there were no occasions when the SPOT failed to enter deep sleep. There was just one disruption and it was caused by a mySQL table crash, but the SPOT stayed up throughout. Its reported up time as well as the time spent in deep and shallow sleep kept rising at a regular clip throughout the experiment. Overall, the SPOT spent nearly 95% of the total time in deep sleep, around 4.5% in shallow sleep and about 0.5% in active computation.
More info on his blog.