Data Sheet

DATA SHEET
Technical changes reserved
0141 0316-365 06/2014
Function
The radar module comprises of a highly integrated radar sensor
with sending and receiving element as well as two push-pull mixer
at around 90° phase shift. The evaluation of movement direction is
enabled by these two available phase shift I/Q signals, because of
which the module is ideally suitable for alarm technology applications.
Careful circuit interpretation and selection of suitable components
ensure that the module meets the requirements of European ETSI
standard and has a universally valid CE-approval..
The Radar movement alarm unit works on the Doppler principle: The
electromagnetic waves sent in the microwave range are reected
from the object and superimposed over the sending signal with the
help of a mixer in the module. Therefore, the signal developed at
the mixer output is proportional to the frequency of speed: 44 Hz
corresponds to a movement speed of approx. 1 km/h. The amplitude
of resulting signal depends on the size of the object and its distance
from the sensor.
While PIR sensors react very insensitively to movements in straight
direction to the sensor, the radar sensor shows its highest sensitivity
here. On the other hand, radar sensors react very insensitively to
circular movements around the sensor, while the PIR sensors straight
away has the highest sensitivity here. Therefore, in modern safety re-
lated applications, the PIR sensors and radar sensors are effectively
combined.
The signal voltage at output of the mixer is relatively low, with a
magnitude of several hundred µV. Hence, downstream ampliers
with dened bandwidth (approx. 20… 900 Hz) are required, which
bring the signal to a utilizable level, which can then be evaluated with
the help of a micro-controller. Application circuits can be received on
request, and alternatively, modules with integrated amplier are also
available.
Handling Recommendation
The sensor is susceptible to ESD danger due to wrong
handling. However, the usual precautionary measu
res for CMOS circuits are sufcient for handling of the
component. Touching the signal outputs should be avoided, before
the module is assembled on the mother board.
The use of a multimeter for resistance measurement between the
connection pins can lead to damage of the module.
The proximity of uorescent lamps can lead to incorrect triggering.
Therefore, the module should not be installed in direct proximity of
uorescent lamps. This effect can be suppressed by a 100-Hz notch
lter in the subsequent electronics.
Because of its type of construction, the modules are sensitive to
sound impacts. Just mounting over the pins is not sufcient, additio-
nally the module should also be mechanically secured.
Connection
Pin Function
1 Not occupied
2 Operating voltage 4.75 ... 5.25 V
3 Signal output 1
4 Ground
5 Signal output 2
PIN: 5 4 3 2 1
Radar movement alarm unit
RSM2650
B+B Thermo-Technik GmbH | Heinrich-Hertz-Straße 4 | D-78166 Donaueschingen
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