Robots can employ many types of sensors with very different operating principles and features to acquire data from the environment. In this article we focus on reviewing sensors which operate by detecting infrared radiation in one form or another. Infrared sensors for robots are used for a variety of purposes, there are IR range sensors used for measuring distances to objects, IR proximity sensors which can successfully replace physical contact sensors, passive infrared (PIR) sensors which can be used to detect motion based on detecting heat radiated by a body, IR sensors used for data transmission — either between robots or with a stationary beacon or base — and positioning, and even gas concentration measurements can be performed with certain types of IR sensors.
Sharp GP2Y0A02YK0F IR Range Sensor
GP2Y0A02YK0F is an infrared sensor build by Sharp and is one of the most powerful infrared sensors that can be used to build a robot.
Sharp GP2Y0A02YK0F is a distance sensor composed of three elements:
- Position sensitive detector;
- IRED (infrared emitting diode);
- Signal processing circuit.
The sensor can detect everything that exists in front of it at a distance between 20 to 150 cm (7.87 to 59.05 in). These values are quite real and make from this sensor a standard of IR sensors for distance. The distance between the sensor and the object is directly proportional with analog voltage value. Information from the sensor can be captured by means of the 3-wire interface.
Specifications
- Operating supply voltage: 4.5 V to 5.5 V;
- Operating supply current: 33 to 50 mA;
- Output terminal voltage: -0.3 V to 5.3 V;
- Detection range: 20 cm to 150 cm (7.87 to 59.05 in);
- Typical response time: 39 ms;
- Typical start-up delay: 44 ms;
- Output type: analog.
DFRobot adjustable IR Sensor Switch
This adjustable IR sensor switch from DFRobot is one of the most well performing sensors for measuring distance. The distance between sensor and object detected can be between 3 to 80 cm. The sensor from DFRobot is perfect for detecting and avoiding obstacles by the robot. It is easy to use, install, does not occupy much space and comes with full documentation. Analog signal varies in value depending on the distance between the sensor and the object detected.
Specifications
- Power supply: 5 V;
- Current: 100 mA;
- Range: 3-80 cm adjustable;
- Red: +5V; Yellow: Signal; Green: GND;
- Model: SEN0019.
Phidgets 1103 IR Reflective Sensor
The 1103 IR reflective sensor from Phidgets is used to detect objects at a distance of up to 10 cm. The sensor works only for objects that do not emit bright light, for example a light bulb, but works equally well in dim and brightly lit environments.
Specifications
- Supply voltage: 4.75 V to 5.25 V;
- Current consumption: 9 mA;
- Output impedance: 1 KOhm.
Sharp IS417F IR Proximity Detector
The IS417F proximity detector from Sharp is an IR sensor that can be used as short-range wide-angle proximity detector or for non-contact bump sensing.
It uses a LED as an IR light source to illuminate the objects. Using this LED the sensor makes the detection, insensitive to ambient lighting.
Dagu Compound IR Sensor
This compound IR sensor from Dagu Electronic can be used to track movement within 200 mm. The negative part for this sensor is that it does not function as set in bright light, such as sunlight, bright light produces a blinding effect for the sensor. Operating mode of the sensor is simple, it sends IR light to the object and follows the light reflected.
Specifications
- Track movement within 200 mm;
- Simple range finder function.
Sparkfun SEN-08630 PIR Motion Sensor
The SEN-08630 sensor can detect movement of living beings that emit heat, it is a sensor that can be used to build robots that need to detect motion in social environments. Motion detection is done by comparison between a snapshot of the environment and what is moving after snapshot, if there is movement, the sensor generates an output.
Specifications
- Product length: 1.27 inches;
- Product height: 1 inches;
- Product width: 0.96 inches;
- Voltage: 3.3 – 5 V.
Pololu IR Beacon Transceiver
The IR beacon transceiver from Pololu is a compact board that is used in pairs to allow robots to locate each other, the idea behind this product is communication between robots. Suppose that two robots want to communicate with each other and know the distance and the direction where is heading one of them. In this case, for both robots such a plate is used which has integrated up to 4 IR sensors. The beacons work by transmitting and detecting infrared light, much like a television remote control.
Specifications
- PCB size: 1.35″ circle;
- IR modulation frequency: 56 kHz;
- Output refresh rate: 20 Hz;
- Detection range: 6 inches to 20 feet;
- Supply voltage: 6-16 V;
- Data voltage: 5 V;
- Number of IR detectors: 4.
Fairchild QRB1134 IR Photoreflector
The QRB1134 is an IR photoreflector sensor that works simply by emitting an infrared light and detect it. Objects that are in front of sensor reflect the light, depending on the distance between sensor and object. Analog output of the sensor is proportional to the amount of light received.
Can be used for line following robots, the optimal working distance of the sensor is 0.5 cm (0.2 inches).
SenseAir CO2 Engine BLG
The CO2 Engine BLG from SenseAir is a non-dispersive infrared (NDIR) sensor for measuring CO2 concentration in the environment. It can be used for robots that work especially in areas with high degree of danger for humans.
The sensor also measures relative humidity (RH) and temperature and can also store logs of its measurements. It is designed to be battery operated. It is equipped with alarm function which is activated if CO2 emissions exceed a certain amount. Measurement ranges are available from 400 ppm up to 30% vol CO2 and it can be configured as flow-through or diffusion sensor.
