This article covers the use of the energy harvesting controller (EHC) implemented on the new RE01 family of embedded controllers from Renesas. The EHC is designed to remove the start-up problem and allow the developer to manage both the start-up cycle of the microcontroller – without taking too much current – and the external power reservoirs. In this case, these comprise storage capacitors and secondary batteries or super caps. This allows the developer to carefully manage the small amounts of energy generated by the energy harvesting power supply and store that energy until needed. The EHC is designed to be flexible enough to work with a wide range of energy harvesting power sources, such as solar cells, thermoelectric generators, vibration harvesters and many other types of power generators.