Sensor Circuit

Discussion in 'The Projects Forum' started by blitzgunner, May 14, 2014.

  1. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    Hi, I am having trouble coming up with a circuit to activate a 12V solenoid when the photo gate sensor detect the object twice.

    The photogate circuit I believe look something like this in general:
    [​IMG]

    Any suggestions on what components and the probable circuit that will be needed to acquire the sensor signal? It do not have to be detail in voltage/resistor and current numbers.

    Right now, I can only think of using ( it could be wrong:confused:):

    1) a relay to separate the solenoid circuit from the photogate circuit, the relay will be switched on through the sensor signal

    2) an amplifier to amplify the sensor signal if needed

    3) flip flop to store the 0-1 state so that the first detection will not activate the solenoid.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You can use a slot sensor such as H22A1 or equivalent, there are a few the same out there, just go to Digikey and plug in opto interrupter.
    Max.
     
  3. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    actually the priority of the photo gate is for detecting the object's velocity, so if possible i would still like to use the same sensor to trigger the solenoid?

    or do I need an additional sensor like interrupter to do the work??
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    The operating principle of your circuit is fine (but you may need to play with component values). The output may need 2 D-type flip-flops to do what you want. A CD4013 is an IC which includes 2 such flip-flops.
    One interrupter can provide the input to do both jobs.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    How are you detecting velocity?
    And what rate?
    Max.
     
  6. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    using a commercial photogate.. it is an infrared emitter and receiver type. but exploring means of using it to activate solenoid

    i not very sure about the rate, but all i need is to do some test to drop an object and for the sensor to detect the object's velocity and then activate the solenoid to catch the onject.. though the sensor will have to detect the object for the second time before the solenoid is activated.
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    So you have, or need some intelligent way of calculating the velocity?
    There are dual head slot detectors that may be set up for velocity detection, but so far the details are a little vague as to what you have and system parameters?
    Max.
     
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  8. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    If possible, reduce Rb2 to less than 1K, or remove it completely and replace it with a short. The 22K resistor in Q1's collector is more than enough base current limiting.

    I don't think you need a sensor amplifier.

    A dual FF such as a 4013 can signal the second trigger after a reset. Connect FF#1 Q- to FF#2 clock. FF#2 Q output will go high on the second trigger. Note that by trigger I mean a positive-going edge out of the Q2.

    ak
     
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  9. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    Thank you.. As of now, i would very much like to stick with using the photogate sensor to detect the velocity. The circuit I provided does not belong to me, just a reference as to what a photogate circuit resembles.

    So at this stage, I just curious what components I might need to allow the activation of solenoid. Also a very brief circuit.
     
  10. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    So using the dual FF, i can just tap onto the sensor circuit? or do i need to use a relay or something to isolate the solenoid circuit from the sensor circuit?

    also, will I still be able to measure velocity?

    Thank you.
     
  11. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Depends on what the solenoid and sensor circuits are. Please post a schematic or drawing or photo or something.

    [/QUOTE]also, will I still be able to measure velocity?[/QUOTE]

    Can't say because you've given us so little information. The sensor is a simple light beam detector, and the output signal changes when the beam is blocked. That can not measure velocity by itself. It can provide the information needed to calculate velocity if you know the length of the object breaking the light beam. With that dimension and an external circuit to measure the length of time the beam is blocked, you can calculate the velocity.

    Or, two sensors can be placed a known distance apart. If the first one starts a timer and the second one stops it, you can calculate the velocity between the two sensors.

    ak
     
  12. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    If you want to measure the velocity of a dropped object you will need two single-slot sensors or one dual-slot type (as Max mentioned). However, to measure, say, the rotation velocity of a disc you could use just one single-slot sensor.
     
  13. t06afre

    AAC Fanatic!

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    What about your other circuitry/instruments? How do plan to measure the speed. As your project is outlined now it gives very little sense
     
  14. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    the photogate is a commercial product comes along with the software and its interface.
    [​IMG]

    But ignoring the commercial product, I believe its circuit still look something like this in general.
    [​IMG]

    I just need to know how I can tap onto it to acquire the signal to activate the solenoid.

    it does not have to be in detail just mainly the rough concepts and electronic parts will do:)
     
  15. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    The question mark is the part which I am interested to know.
     
  16. eetech00

    Active Member

    Jun 8, 2013
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    Do you have a part number or model number of the sensor being used?

    eT
     
  17. t06afre

    AAC Fanatic!

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  18. blitzgunner

    Thread Starter New Member

    May 6, 2014
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    I using Neulog photogate. here is the link: neulog.com/Photogateloggersensor.php
     
  19. Alec_t

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    That photogate requires a proprietary adaptor ('USB-200 module' or 'WIFI-201 WiFi module') to connect it to a PC or tablet.
     
  20. alfacliff

    Well-Known Member

    Dec 13, 2013
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    if your measuring velocity with this, then yyou must know the length of the object. that determines how long a pulse is produced as the object passes through the detector beam. an easier method is to use two sensors spaced a known distance apart, the first to start a count, and the second to end the count. why do you need to activate a relay and know the velocity of the object at the same time? relays are notoriously slow.
     
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