ZigBee RangeFinder
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Telegesis ZigBee RangeFinder
Power
The HHT is powered by rechargeable NiMH batteries which are charged through the USB
connection.
Batteries
The unit takes two 1.2 V 2000mAH NiMH batteries. To conserve the power consumption the unit
will turn itself off after a period of inactivity. The battery compartment is accessible on the back side
of the HHT and can be opened using a coin as shown in the Layout section. The battery
compartment is designed to take 3 AA cells hence the extra space is blanked off using a dummy
pass-through AA cell which should not be removed. The battery state is shown on the Home
screen using the following symbol,
Figure 28: Battery Symbol
The above symbol is showing 50% battery charge remaining.
Charging
The HHT can be charged or powered using the USB port connection. The USB connector is a USB
“B” Micro socket. The detection of the USB power source is indicated by a beep from the built-in
buzzer. The HHT does not go to sleep while it is powered from USB power source. The charger
charges the 2000mAh batteries at C/10 rate and it terminates the charge via voltage detection and
a 12 hour timer. The power requirement for charging as well as operating the unit is 1.5Watts at 5
Volts. The charging state is shown on the Home screen by showing the following the symbol,
Figure 29: Battery Charging Symbol
The charging symbol shown above is replaced with the battery capacity remaining symbol as
shown in Figure 28: Battery Symbol once the charging is finished.
Power Saving
The HHT incorporates several ways to reduce power consumption and extend battery life. Most of
the power is consumed by the LED backlight for the screen so it is important to turn off the
backlight when not needed; the backlight is turned off in the following instances:
a) No key press by the operator for 10 seconds
b) 60 Seconds after a test has been completed
Moreover the unit is turned off after a period of inactivity of 15 minutes to save power. This 15
minutes is counted from the time the unit is turned on using the
and will be extended by 5
minutes if the user presses a key or a test is underway and the unit is in the last 5 minutes of the
15 minute wake period.
