My system consists of two
XBee S1s and a
Raspberry Pi. I've attached a
TMP36 sensor and a
LDR to the first
XBee S1 and transmit those infromations to the second
XBee S1 via the ZigBee protocol. The second
Xbee S1 is connected via USB adapter to the
Raspberry Pi. My first
XBee S1 is powered by batteris at 5V.
As the voltage given by the batteries decreases over time, I would like to have an indeication of the voltage supplied by the batteris in order to know when I should change them. Can you tell me how can I do that? My idea is to make a gauge with 4
LEDs attached to the Raspberry Pi. The problem I am facing is that I do not know how can I send the supply voltage via the Xbees(as the XBee 1 itself is powered by that battery).
PS: I don't want to use a multimeter every time I am wondering how much voltage is provided by the batteries.