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Sensors you should know about

Sensors you should know about. Thomas Edwards http://www.t11s.com. Passive Infrared (PIR) Sensor. Detects motion of warm moving objects If nothing is moving, there is no detection Commonly used in security systems Very Long range (50 feet) Binary or relay opening output ~$10

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Sensors you should know about

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  1. Sensors you should know about Thomas Edwards http://www.t11s.com

  2. Passive Infrared (PIR) Sensor • Detects motion of warm moving objects • If nothing is moving, there is no detection • Commonly used in security systems • Very Long range (50 feet) • Binary or relay opening output • ~$10 http://www.mpja.com/directview.asp?product=15840+SC http://www.parallax.com/detail.asp?product_id=555-28027

  3. Microwave Motion Detector • Uses microwave doppler shift to detect motion • Range 10 feet • May have fewer “false positives” than PIR detectors • ~$35 kit http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=MD3C

  4. Active IR Sensors • Bounces invisible IR beam off of target • Uses triangulation to determine distance • Range up to 5 feet • Analog distance output or binary fixed range detection output • ~$10-$20 http://www.acroname.com/robotics/parts/c_Sensors.html

  5. Ultrasonic Sensors • Uses travel time of sound echos to detect distance • Range up to 15 feet • Outputs can be analog, serial, or PWM • Old, expensive Polaroid sensor • New, cheaper ones today ~$25 http://www.maxbotix.com/

  6. Accelerometers • New ones based on Micro-Electro-Mechanical Systems (MEMS) devices very small • Can measure acceleration in up to three axes • Even can sense gravitational pull of earth • ~$25 and up http://www.sparkfun.com/commerce/product_info.php?products_id=692

  7. Magnetic Reed Switches • Magnet in one part causes reed switch to open/close on second part • Commonly used in security systems • Range very short (~1 inch) • Good for limit switch • ~$5 or under

  8. Force Sensing Resistors • Pressure reduces resistance • Analog voltage measured across resistor divider circuit • Can measure a few ounces to 100 lbs depending on model • ~$10-$25 http://www.parallax.com/detail.asp?product_id=30056 http://www.phidgetsusa.com/cat/viewsubcategory.asp?category=5000&subcategory=5210

  9. Touch Sensors • Measure changes in capacitance • Can sense touch through 4 inches of dielectric objects (glass, plastic) • ~$10-$20 http://www.phidgetsusa.com/cat/viewproduct.asp?category=5000&subcategory=5100&SKU=1110

  10. CMU Cam • Microcontroller and camera combo • Track user defined color blobs • Track motion using frame differencing • Controls up to 5 servos • Other video processing capabilities • Serial I/O • $169 http://www.cs.cmu.edu/~cmucam2/

  11. Laser Range Finder • Very accurate distance measurement • Time-of-flight determines distance • Range 4m • 270 degrees of measurement • 0.36 degrees angular resolution • RS-232/USB output • $2695 http://www.acroname.com/robotics/parts/R283-HOKUYO-LASER1.html

  12. Sensors you should know about Thomas Edwards http://www.t11s.com

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