I have a project to design that needs to be battery operated and last as long as possible, I am looking at using a low voltage mcu like a pic16lf1455 a lm35 and a pressure sensor and a speaker with small possibly push/pull or op amp for output. I figured I could try and run the mcu in extreme low power mode with timers to put the mcu to sleep and use the pressure sensor as an interrupt. with this in mind, how do I go about searching for and choosing a buck/boost converter that will drive the circuit while using something like 3 AA or 1 9v battery?