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BT47i Exercise Heart Rate sensor User’s Guide
Short description
The Exercise Heart Rate sensor BT47i
monitors a person’s heartbeat. The
sensor consists of a transmitter belt and
a receiver. The transmitter belt has to be
worn around the chest and held in place
the elastic strap. The transmitter detects
electrical signals at the surface of the
skin by two electrodes embedded in the
chest belt and transmits the information
to the receiver via a low frequency
electromagnetic field. The reception
range of the receiver is circa 80-‐90 cm.
Each time the heart beats an electrical
signal is generated. By graphing this
signal the heart rate can be determined.
The transmitter switches off automatically as soon as there is no skin contact
between electrodes and the belt. The battery in the belt has a lifetime of about 2500
transmit hours. When the battery gets weaker, the range of transmission gets
smaller. Then the chest belt has to be replaced
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The CMA Heart-‐rate sensor can be directly connected to the analog BT inputs of the
CMA interfaces. The sensor cable BT -‐ IEEE1394 needed to connect the sensor to an
interface is not supplied with the sensor and has to be purchased separately (CMA
Article BTsc_1).
Sensor recognition
The Exercise Heart Rate sensor has a memory chip (EEPROM) with information about
the sensor: its name, measured quantity, unit and calibration. Through a simple
protocol this information is read by the CMA interfaces and the sensor is
automatically recognized when it is connected to these interfaces.
If your Exercise Heart Rate sensor is not automatically detected by an interface you
have to manually set up your sensor by selecting it from the Coach Sensor Library.
Calibration
The CMA Exercise Heart Rate sensor BT47i generates a 5V pulse for each heartbeat.
By graphing this signal the heart rate can be determined. Another method is using
the sensor as a counter and count the number of pulses in a unit of time.
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Compatible with T31 chest belt of POLAR (www.polar.com)
