Doppler Sensor Application
1. Principle:
Microwave Doppler motion sensor uses the Doppler shift phenomenon to "sense" motion..
The MDU (Motion Detector Unit) is a miniature microwave Doppler radar sensor which has low
power consumption, short range and low cost. The circuit features a dielectric resonator which
provides stable operation over a broad temperature range in either CW or low duty cycle pulse
mode and a balanced mixer for enhanced sensitivity and reliability.
The MDU emits a low level 5.8GHz microwave signal which is reflected from all objects within
its coverage area. If any of the objects that the signal has bounced off are moving towards or away
from the sensor, the frequency of the reflected signal received back by the sensor will be increased
or decreased from that of the transmitted signal by the Doppler effect.
The MDU compares the transmitted and received frequencies and produces an output signal, the
frequency of which is proportional to the velocity of the object. The amplitude of this signal is a
complex function of the size and reflectivity of the object and its distance from the MDU, as well
as the characteristics of the MDU.
Signal processing circuitry amplifies this signal and analyses its frequency spectrum. If the signal
strength is above a threshold level, and has the required frequency spectrum an output signal can
be generated.
In order to conserve power it is usual for the MDU to be pulsed on and off rapidly so that it is only
transmitting for approximately 5% of the time. As well as reducing power consumption, this also
reduces the average power transmitted. This does not reduce the ability of the MDU to detect
moving objects.
2. Applications :
Light control
Security product (sensing device, alarm etc)
Traffic/highway observation and control
Automobile rear sensing
Automatic door
Possible to apply to all product by working with sensor
FCC Caution
§ 15.19 Labelling requirements.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
§ 15.21 Information to user.
Any Changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment.
§ 15.105 Information to the user.
Note:
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates uses
and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of
the following measures:
-Reorient or relocate the receiving antenna.
-Increase the separation between the equipment and receiver.
-Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
Module use requirements
integrator shall apply a label in a visible area on his product with the following statement:
Contains Transmitter Module FCC ID: 2ADDD-0580WA
This equipment has been tested and found to comply with the limits for a Class B digital
-Consult the dealer or an experienced radio/TV technician for help.
If the FCC ID is not visible when the module is installed inside another device, the OEM
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