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README.md

+# SafePI 1.0
+
+SafePI is an expansion board for RaspberryPI 1 model B, 2B or 3 providing power supply protection and safe shutdown
+by using 4 common available AA rechargeable Ni-MH batteris
+
+It notify the Raspberry when primary power is absent on a configurable GpIO (pin 36 or 38) and then give enough time 
+to shutdown from the batteries. 
+
+When the RPi is on and the primary power is connected, it recharge the batteries.
+
+It provide safe voltage regulator giving the ability to power the RPi from 8V to 25V. 
+
+Battery drain when switched off if minimal (less than 10mA/h)
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