IR Motion Detector alarm


Rating: 0.00 / 5 
Alarm Circuits / Security Circuits
This type of motion detector uses the same basic concept as the active infrared motion detector. An interruption in a 5 kHz modulated pulsating beam that is transmitted by an infrared diode and received by an infrared transistor sets off the alarm.

IR Motion Detector alarm - img1

For our project, we decided to construct an active infrared motion detector. Originally, we wanted to build both an IR and an ultrasonic detector, but we decided that an ultrasonic detector would require too much time for a three week project. The circuit on the left is the transmitter circuit that establishes a 5 kHz modulated infrared beam. As you can see from the schematic of the receiver circuit, a resonance-tuned narrowband amplifier reduces the detector`s sensitivity to stray light. C1 and L1 in IC2A`s feedback loop cause the op amp to pass only those frequencies at or near the LED`s 5 kHz modulation rate. IC2B`s output increases when the received signal is sufficient to drop the negative voltage across C2 below the reference set by R2. The output of this circuit is then attached to some load resistance, which can be an alarm or, for demonstration purposes, an LED. However, we also decided that just building an IR motion detector would probably be a trivial exercise. So, we decided to expand on the concept by building an ambient light ignoring motion detector.

Recommended videos

  • PIR Sensor Based Security System
    Duration: 2:05.
  • Laser Light Security Alarm Circuit
    Duration: 0:45.
  • [D.I.Y.] How to make an infrared motion detector
    Duration: 6:24.


  • Vehicle security expert says systems inadequate
    Jamaica Gleaner
    Jamaica Gleaner alert - Vehicle expert says systems inadequateEvon Vassell of Diplomat Tracking Solutions Ltd has little comfort for motorists using one – or both – of the most popular methods of thwarting motor vehicle thie
     24 July 2016
  • The Boston Globe
    The Boston Globe Does the Massachusetts Bay Transportation Authority have a data problem? The T is becoming more transparent with data in many ways, as a fiscal control board and Governor Charlie Baker's administration try to turn around the
     23 July 2016
  • The Telegraph
    The Telegraph Earlier that week, Davis already encountered several other suspicious packages in the park that turned out to be false . “To me, this one wasn't any different,” Davis said. “I thought it would be the same.&rdqu
     23 July 2016
  • The Boston Globe
    company investigatedBut Leonora Lamothe, a Chicopee retiree, said she had repeated problems with her Safe Home system. She installed it in her house in 2010, but a few years later started going off in the middle of the night. She tried mu
     23 July 2016
  • Security Sales & Integration
    Security Sales & Integration Technologies to Solve Age-Old ProblemsHAVING owned and run a small dealership, I always found that one of my most exciting tasks was taking existing technology and reshaping it to fit my customers' spec
     21 July 2016
  • Boulder Daily Camera
    rate on home systemsA spokesman for the industry said that his stakeholders, including the Colorado and Fire Association, are supportive of the policy, and that Boulder can reasonably expect a 50-percent reduction in false two years af
     20 July 2016
  • Kansas City Star
    Kansas City Star about safety and Players focused on their Pokémon Go quests have been locked inside closed warehouses and cemeteries, pulled back from an open windowsill and walked into streets oblivious to traffic. So it had to
     20 July 2016
  • PC Advisor
    PC Advisor cameras for home use 2016 | Best smart home To help you choose the best camera, we'll explain the key features to consider. Whether you're looking for an easy way to check on your children and pets, or a motion detection syst
     13 July 2016
  • The Lawton Constitution
    A City Council study committee has recommended that the city impose the restrictions already contained within city code with some revisions to curb incidents of false from home and commercial systems. Council members had been asked by 
     10 July 2016