Step 2: Carefully take out the front cover of the sensor
Step 3: Insert the type AA battery, please take note the polarity of battery
Step 4: Turn the front cover of the sensor clockwise to close fully.
ATTENTION:
REVERSED POLARITY OF BATTERIES IN 10 SECONDS CAN DAMAGE THE SENSOR CIRCUIT!!!
NOTES:
Using 2mm hex key to lock the cover to prevent the unattended opening.