I've noticed that it is common for the Samsung Galaxy Smart Camera to not turn on after charging or after being idle for a while.
This is what I usually do when it happens:
# 1: Disconnect charger from Samsung Galaxy Smart Camera
# 2: Disconnect battery from Samsung Galaxy Smart Camera
# 3: With battery disconnected out of the device, reconnect it
# 4: With battery back in the device, press and hold the power button until it boot, usually after 5 seconds.
# 5: Device should turn back on and you can resume doing whatever you want with it.
Hopefully this help.