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QRD1113 Reflective Object Sensor — Parallax Forums

QRD1113 Reflective Object Sensor

TebosTebos Posts: 11
edited 2009-04-25 19:43 in Accessories
Hello all,

I am building a maze solving robot and am trying to use some QRD1113 (·http://www.fairchildsemi.com/ds/QR/QRD1114.pdf) sensors.· I am using a BS2 on a super carrier board.· I tried following the testing instructions in some of the manuals but have not been successful.· I believe i wired it correct....pin 1 VCC pin 2 BS2 input pin, pin 3 BS2 output pin and pin 4 GRD (and many more configs confused.gif ).· I included the 1k and 220 resistors in the circuit but am not sure if these are correct since they are not the same IR sensors as manual.·· Any input will be greatly appreciated, thanks for your time.·

Comments

  • kwinnkwinn Posts: 8,697
    edited 2009-04-25 14:15
    If you are using a 5V supply you will need a 150-180 ohm resistor to limit the diode current to about 20mA, which is what they used to produce the collector current vs distance curve.

    The curve shows a collector current of 0.4mA when the reflector is approximately 1/10th of an inch from the surface, so to get a 5V drop you would need a 12K (5/0.0004) resistor on the collector of the phototransistor.

    These values would be starting points only, since the sensor distance from, and the reflectivity of the surface may be different.

    The diode current can be increased by decreasing the value of the current limiting resistor, but I would not go lower than 100 ohms or the diode will be damaged.

    The sensitivity of the detector can be increased by putting a higher value resistor on the collector of the transistor or connecting another transistor (like a 2n3904) to the phototransistor in a darlington circuit.
  • TebosTebos Posts: 11
    edited 2009-04-25 19:35
    Im still have issues with these sensors confused.gif, does anyone else have any info?
  • FranklinFranklin Posts: 4,747
    edited 2009-04-25 19:43
    What issues and could you include a drawing of how you have it connected. Have you tried the things kwinn suggested?

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