Question

We went over Sensors in class. There are other types of third party sensors that work with the EV3 (or the NXT). Describe what these types of sensors would be used for and how they work. They can be short descriptions, but each sensor description should be about three lines and in plain English. Tell the name of the third party company that sells the sensor and how they can be used with the EV3 or NXT (ex. some may need a sensor adaptor to use on some versions). You can check our book, the lejos.org web site, etc. Include references, reference links, etc. to cite your sources. Attach a file with your descriptions and submit.  

PIR Sensor

Barometric Sensor

Force Sensor

O2 Gas Sensor

Relative Humidity Sensor

Answer 1

The PIR sensor for Lego Mindstorms NXT

PIR stands for "Passive Infrared". The PIR sensor for Lego Mindstorms NXT is then a passive infrared sensor. This is the technology used by motion detectors in an alarm system for a house. The principle of PIR sensor is that- all objects, people and animals emit infrared radiation. The warmer the object is, the stronger the infrared emission.

The PIR sensor for NXT therefore detects changes in infrared radiation in its field. Thus, a person or an animal (warm blooded) that moves in the field of the PIR sensor will be detected. If the person or the animal remains stationary in the field of PIR, then the detection will fade gradually. The sensor detects movements.

This sensor is effective for people, animals or objects at temperatures between 30°C and 50°C.

Company that sells PIR sensor:

• Senba Sensing Tech

The Barometric Sensor:

The Barometric Sensor Block gives the access to both the pressure and temperature data from the sensor. The block allows us to select either metric or imperial units. For pressure, the data can be in either in 1/1000th inch of mercury or 1/10th hectopascals. For temperature, the data is either in 1/10th degree Fahrenheit or 1/10th degree Celsius. Note that the native temperature data from the sensor is in Celsius so the Fahrenheit value does not represent actual resolution.

In addition to pressure and temperature data, the NXT-G block also gives a calculated altitude value in either feet or meters. By default, the altitude calculation is based on a "standard atmosphere" with an altitude pressure at sea-level of 29.921 inHg. The NXT-G block also adjusts this base altitude pressure by either specifying the known current altitude or by supplying an altitude pressure at sea-level that represents your current conditions.

Company that sells Barometric Sensor:

• HiTechnic
• Generation Robots

Force Sensor:

The NXT Force Sensor will enable us to build robots that can measure a physical force applied through a LEGO cross axle. The sensor has a LEGO cross axle receptacle and the value represents the force that is applied to an axle going into the sensor. Note that the force measured is the linear force going into the sensor.

This sensor can be thought of as an analog touch sensor. Unlike a touch sensor, which gives just a binary value indicating pressed or not-pressed, this sensor gives you a numeric value based on how hard the axle receptacle is pressed.

Note: The sensor value does not directly translate into force. With calibration the value can be used to determine the approximate weight of an object. Build the sensor into your robot so that the weight of the object becomes a force pressing into the sensor. Now the sensor value can determine the weight of the object.

Company that sells Force Sensor:

• HiTechnic

O2 Gas Sensor:

The O2 Gas Sensor measures oxygen concentration in air, and is temperature compensated for use in different environments. It has a wide measurement range, allowing it to be used to study human and cellular respiration. The O2 Gas Sensor also includes a 250 mL bottle that can be used to study the rusting of iron or as a respiration chamber for monitoring plants and insects.

Relative Humidity Sensor:

Measure temperature and humidity using these sensors. These sensors can be used as external sensors (environmental sensors) or as internal sensors to the robot.

References

(n.d.). Retrieved from www.vernier.com: https://www.vernier.com/products/sensors/o2-sensors/o2-bta/

(n.d.). Retrieved from www.generationrobots.com: https://www.generationrobots.com/en/342-temperature-and-humidity-sensors

(2018, 06 28). Retrieved from www.hitechnic.com: http://www.hitechnic.com/cgi-bin/commerce.cgi?preadd=action&key=NBR1036

401146-nxt-barometric-sensor-hitechnic-for-lego-mindstorms-robots. (2018, 06 28). Retrieved from www.generationrobots.com/: https://www.generationrobots.com/en/401146-nxt-barometric-sensor-hitechnic-for-lego-mindstorms-robots.html

lego-mindstorms-nxt-pir-sensor-hitechnic. (2018, 06 28). Retrieved from www.generationrobots.com: https://www.generationrobots.com/en/401150-lego-mindstorms-nxt-pir-sensor-hitechnic.html