WEEK 9 (20 - 24 Sept 2010)

1. Triangular Sensor

Triangulation sensor

Optical Triangulation Sensors are commonly used to provide door mounted safety detection on swinging automatic doors.

These types of sensors are very common and manufactured in very high volumes. When automatic swinging doors open and close, it is important that they do not come into contact with pedestrians passing through the door.

Sensors used in the automatic door industry typically fall into four categories:

1. Microwave Sensors used to detect motion of a person as they approach an automatic door,
2. Reflective Optical Sensors that are mounted on the door header and detect the presence of a person in the door path
3. Camera based sensors that are also mounted on the door header and detect presence (a competing technology to Reflective Optical Sensors); and
4. Triangulation sensors which are mounted on the door and move with the door to provide safety.

Reflective and Camera technologies do not perform well on moving swing doors, because they typically depend upon detection of changes in the background. A sensor mounted on a swing door system is constantly in motion, so the background (i.e. floor beneath the door) changes continuously. To overcome this problem, a triangulation sensor provides an innovative solution.

2. Infra Red Sensor

 Infrared Sensor

 An infrared sensor is an electronic device that emits and/or detects infrared radiation in order to sense some aspect of its surroundings. Infrared sensors can measure the heat of an object, as well as detect motion. Many of these types of sensors only measure infrared radiation, rather than emitting it, and thus are known as passive infrared (PIR) sensors. 

Honeywell infrared detectors control or generate an electric current when irradiated. These metal or plastic products are available in a variety of electro-optical characteristics, package styles and mounting configurations. Often used with a corresponding emitter.

Best Used For:
Applications requiring object presence and limit sensing, position encoding, movement detection and counting. 

3. Ultrasonic Sensor

 
 

Ultrasonic sensors (also known as tranceivers when they both send and receive) work on a principle similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the echo to determine the distance to an object. 

Ultrasonic Sensor Compact Ultrasonic Sensor suitable for dual use, with high-performance characteristics. Standard operating frequency and good sensitivity. Ideal for use in range measurements, robot applications, alarm sensors, etc.
Part Code: US1240
Features • Excellent Directivity and Sensitivity • Detection Range: Up to 12m • Nominal Frequency: 40kHz • Operating Temperature: -30oC to +85oC • Dimensions: 12mm Diameter, 10mm High excluding pins, Pins - 5mm High