For orienteering, I'm considering building an ibutton device. The runners carry a button (4096 bit NVRAM) and click into each control point where their button gets the time at that control. The final control has RS232 or other external comms to a laptop which displays scores.
The control points need an battery powered MCU with piezo, LED and possibly EEPROM attached via the 1-wire bus to a button socket.
The question is, what's the minimum power required to run the control point? Is it possible (say with a small MSP-series) to idle the reader in the uA range so it doesn't need a switch?
Can you point me to any published low-power ibutton designs?
Clifford Heath.