Motion sensor is a device which can detect the motion of any object.motion detector sensors are used in many places like Hotel elevator , and also used as security system to detect the motion of any thief who entering in any private property.
A motion sensor can uses one or more technology to detect the motion of any object.As their are any disturbance in the environment then the signal(pulse) pin of the sensor become high and A Op-amp is used to convert the pulse signal of the sensor into the digital output.
this output signal(high logic) then goes to the control system and micro-controller give the specific task to the system or actuators like when the motion sensor detect any object then at that instant buzzer also activated.
HOME security system also used this sensor to detect the change in the energy of the environment.A security system used the GSM module to make it more reliable. we can interface these sensor and gsm module with any micro -controller like 8051.
THERE ARE TWO TYPES OF MOTION SYSTEM
1.Passive motion sensor
2.Active motion sensor
PASSIVE MOTION SENSOR
passive motion sensor do not emits any radiation but it reads the change in energy of the surrounding area.it measure the infra red light which is coming from the object.
WORKING PRINCIPLE OF PASSIVE MOTION SENSOR
As we know that the body which have temperature higher then the absolute temperature of the environment then they emits thermal radiations.these radiation does not detected by human eyes because they are within the range of infra red light. but motion sensor can easily detect these radiations .passive sensor does not emits any radiation but it detects only the radiation which are coming from the object.these are mainly used in home security system.
these are mainly used in the automatic sensing system like room light controlling and remote sensing.
ACTIVE MOTION SENSOR
the active motion sensor emits the radiation or a wave signal like sound wave or a microwave. these types of waves are reflected by surrounding .the reflected signal received by the sensor and these reflected signals are amplified by an amplifier to make the signal more effective to give the logical signal [logical signal is received by an op-amp because we know that the op-amps are used to convert the analog signal (which is coming from the sensor output signal port) into the digital signal ] to the controller and then microcontroller take the desired action.
WORKING PRINCIPLE OF ACTIVE MOTION SENSOR
when we put the whole system into the surrounding. initially(when there is no disturbance into the surrounding ) the system logic is low . but if their is any movement or disturbance in the surrounding the wave or radiation that are emits by the the sensor is reflected from the disturbance or or due to presence of any object in the surrounding.
these reflected signal then received by the amplifier which amplify the signal and then these signal goes to the op-amp. op-amps are basically used in every sensor to convert the analog signal into the logical signal. then these signal further go to the microcontoller to make it high.active type of motion sensor are basically used in home security system.
TYPES OF MOTION SYSTEM
1.Passive infrared motion sensor
2.microwave motion sensor
3.ultrasonic motion sensor
PASSIVE INFRARED MOTION SENSOR
short form of the this type of sensor PIR sensor or also we can call it as pyroelectric infrared sensor. PIR sensor basically detects the heat radiation (infrared radiation ) released by the human or also animal. passive infrared motion sensor is more sensitive to the temperature.
it can detect the motion within the rang of 5m to 10m or also more than it depends upon the sensitivity.PIR sensor can also set at the certain value of heat to detect only person not the animal or small insects for home security purpose.these sensors are small, inexpensive,and easy to use.
MICROWAVE MOTION SENSOR
microwave motion sensor is more sensitive then the PIR motion sensor.but they are more expensive. microwave motion sensor emits the microwave into the surrounding and these microwaves reflected by any object and receive again by the sensor.
then the sensor read the return signal and check the different between the emitted and reflected micro-waves and allow the system to do specific task.these are more reliable over the longer distance than the other one. they can sense the disturbance through any wall.but these microwave are harmful for human.they are less popular because they are more expensive.
ULTRASONIC MOTION DETECTOR SENSOR