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PIR Sensor Rev B question — Parallax Forums

PIR Sensor Rev B question

thorobredthorobred Posts: 5
edited 2014-02-20 21:59 in Accessories
Hello I wanted to know if the PIR Sensor can detect small objects the size of a skittle? Also can this sensor trigger a seven segment display timer when an object is sensed? I would really appreciate it if someone can give me a response.

Comments

  • PublisonPublison Posts: 12,366
    edited 2014-02-16 12:42
    thorobred wrote: »
    Hello I wanted to know if the PIR Sensor can detect small objects the size of a skittle? Also can this sensor trigger a seven segment display timer when an object is sensed? I would really appreciate it if someone can give me a response.

    A PIR sensor normally relies on a change of temperature:

    http://en.wikipedia.org/wiki/Passive_infrared_sensor

    Could you tells use about your application?
  • thorobredthorobred Posts: 5
    edited 2014-02-16 13:33
    Publison wrote: »
    A PIR sensor normally relies on a change of temperature:

    http://en.wikipedia.org/wiki/Passive_infrared_sensor

    Could you tells use about your application?

    What I would like to do is use an IR sensor to detect when a small object passes. Once the sensor detects it, it will trigger the the seven segment display to keep track of it and increment me the value of the seven segment display.
  • garyggaryg Posts: 420
    edited 2014-02-16 15:22
    To do what you are describing will take a bit of research on your part.
    I have a couple of PIR sensors in use in an outdoor environment.
    The PIR sensors activate on IR temperature change.
    They work pretty good at detecting Rabbits and such.
    I think what you are after for detecting would be possibly something like this; http://www.parallax.com/product/350-00029
    It's a photo Transistor.
    Once the phototransistor is working,
    You will need to figure out how to drive your 7 segment display.
    In addition to the 7 segment display, I would imagine you want to count the skittles or what ever small object you are detecting.
    Basic Stamps would work or a Propeller.
    So the project you are considering has a number of different steps.

    I hope my ramblings here have helped you in some manner.
    Garyg
  • thorobredthorobred Posts: 5
    edited 2014-02-20 07:56
    garyg wrote: »
    To do what you are describing will take a bit of research on your part.
    I have a couple of PIR sensors in use in an outdoor environment.
    The PIR sensors activate on IR temperature change.
    They work pretty good at detecting Rabbits and such.
    I think what you are after for detecting would be possibly something like this; http://www.parallax.com/product/350-00029
    It's a photo Transistor.
    Once the phototransistor is working,
    You will need to figure out how to drive your 7 segment display.
    In addition to the 7 segment display, I would imagine you want to count the skittles or what ever small object you are detecting.
    Basic Stamps would work or a Propeller.
    So the project you are considering has a number of different steps.

    I hope my ramblings here have helped you in some manner.
    Garyg

    why use a phototransistor just out rather than a IR sensor out of curiousity?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2014-02-20 08:42
    For an application as you're describing you really would need to give details of not only the relative size of the object, but how it is travelling (conveyor belt?), direction of detector? Really all the details because this information greatly affects how you go about detecting the object. Also, is the object hotter than the ambient temperature? If not a PIR sensor won't work anyway.
  • thorobredthorobred Posts: 5
    edited 2014-02-20 20:17
    Chris Savage wrote: »
    For an application as you're describing you really would need to give details of not only the relative size of the object, but how it is travelling (conveyor belt?), direction of detector? Really all the details because this information greatly affects how you go about detecting the object. Also, is the object hotter than the ambient temperature? If not a PIR sensor won't work anyway.

    The object is a skittle and its traveling free fall on a binary tree design at a 45 degree angle from the ground. What I would like is when the skittle falls out of a hopper, I want the detector to to trigger a timer(seven segment display) to time how long it will take for X amount of skittles fall through the binary tree. I also want another detector to count how many skittles come out into the bin and that will be shown on a lcd.
  • garyggaryg Posts: 420
    edited 2014-02-20 21:59
    HI
    This is starting to sound like either a homework project or top secret development of some type.

    If it's a homework project, answer each suggestion posted in post #4 of this thread.

    If you are attempting to find the answer to particulars about a development project you are thinking about,
    you may want to provide further information as was asked in post #6.

    Lots of people here are willing to discuss, help etc. but facts are needed.

    I hope these suggestions help you out.
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