@jcaron Thanks for your reply. 1.) I would say everything below 5 seconds is acceptable. 2. / 3.) This question is hard to answer, since I will try the device with different types of applications so the capacity of the batteries will strongly vary. The battery life should be as long as possible. I also found the machine.idle and machine.sleep in http://docs.micropython.org/en/latest/wipy/library/machine.html. Given the description machine.sleep should work if I trigger the LoPy through Wifi. Is that correct? Thanks in advance.