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PIR operated DC motor project odd behaviour help

Discussion in 'Sensors and Actuators' started by spyder9, Feb 15, 2017.

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  1. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    OK, this is not a substitute for a proper supply but once you have one and if you still have spike issues you can try this circuit. I replaced the 7808 with a simple RC filter that should tame any spike noise on you supply. Making R1 higher, say 10Ω, will help filter things even more but its value must be made small if the relay you choose is a heavy duty model that pulls a lot of coil current. This is because the lower the resistance of the coil the more current it will demand. The more current it demands the higher the voltage drop across R1. C3 & C4 aren't critical and can be larger if you like, say 100uF or even higher.

    BTW, the voltage rating of your PIR (5V to I forget) should never be used as a proper operating voltage. This is because minimums and maximums are just that. If minimum is 5V then I would not go below 6V and if 25V is maximum then I wouldn't even exceed 23V. You always want a safety margin.

    Chris
    PirSwitch2.png
     
  2. spyder9

    spyder9

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    Feb 15, 2017
    I will try this circut as soon as possible
    And then i'll get a proper supply

    Is it possible that i have damaged my pir
    Because when i connected it to my supply i got 26v on the output with no load
    But on pir input i had 19v

    Also i would like to replace relay with a mosfet,so can You just help me how to connect it in this circut.

    Ivan
     
  3. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Later today I'll redraw the circuit using a MOSFET. BTW, what value electrolytics do you have on hand? I ask because you can tame your charger output with a 1000uF or larger. That said you could very well have exceeded the max voltage of your PIR. If you have a large electro you will see the output voltage of your charger go up quite a bit.

    Chris
     
  4. spyder9

    spyder9

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    Feb 15, 2017
    Can't open charger it is a sealed type
    I connected pir to my other phone charger just to test,a 7v one
    And it works fine,opens and closes as it should

    I can get any capacitor,i have very good electronic shop in my city
    Right now i have 2200uF
    Few 270,50, and 47
    All 16v rated from some old radio
     
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Spyder, I just arrived home after being out of town. While I'm modifying the schematic please tell us what this motor is driving. More to the point, .. What is the scope of you're project?

    Chris
     
  6. spyder9

    spyder9

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    Feb 15, 2017
    Wiper motor is driving bicycle gear,which is connected to another,bigger gear with chain and that drives some kind of dog food dispencer,it is not very heavy load but it needs to be reliable
    Motor needs to be activated by ir diode (which is working fine)...IR is detected by pir
    Which needs to let current to the motor,power it and when IR signal stops,after PIR delay time to turn off motor.
    And if possible to have same supply for circut and motor,not seperate ones

    Ivan
     
  7. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Spyder, I'm well versed in the psyche and basic nature of Dogs. The vast majority of them will eat as much as you give them. They'll do it as though it's the last meal they'll ever get! ,,Like light speed! If you don't stop supplying it they'll keep woofing it down until they explode! There's nothing in your circuit requirements that addresses this. Have you given this any thought?

    Chris
     
  8. spyder9

    spyder9

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    Feb 15, 2017
    I have sent you a conversation message explaining some details about this so if you can,read it

    Ivan
     
  9. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Hi Spyder,
    Thanks for the PM and critical information you provided. Now that I have a clearer picture of what you're designing I can tell you that your PIR Sensor / Switch makes little sense for use in your prototype. An Optoisolator would be far more logical. After all, you're not using it to detect an IR signature of animal or human.

    We often have budding inventors posting here and like you they don't want to reveal the end goal of their project. I believe we can keep the secret element of this project between us without revealing it to the board. That said this is an educational forum and it's for this reason that I don't do design work via PM.

    Later today I'll post a new schematic utilizing an Optoisolator in place of your PIR. In the interim Google the 4N33 Optoisolator. It should be easy to find the datasheet that explains its theory of operation and provides full specs .

    Chris
     
  10. spyder9

    spyder9

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    Feb 15, 2017
    I really never heard of that 4N33 Optoisolator
    That is why i decided to try with PIR
    Thank You for your help,and i have no problem to have all of this project discution here on forum page
    I just wanted to send core details to your PM
    Now i will go and learn something about this
    Optoisolator

    Ivan
     
  11. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
  12. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
  13. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Do you want the GSM or Phone to share the same 12V supply too? If so what's the operating voltage of the GSM or Phone that you're using?

    Chris
     
  14. spyder9

    spyder9

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    Feb 15, 2017
    No no,phone has seperate supply,via own charger,i would like to keep it that way.


    Sorry for late answers but time difference is i think 6h
     
  15. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Hi Ivan,
    Sorry for the delay in posting this but I needed to resolve an issue with J1and P1 on my schematic. My schematic editor/spice simulator (Tina) provides the schematic symbol you see but to invisibly connect them they provide an "Additional Nodes" property with absolutely no help files explaining syntax structure to do so. I had to build a Macro circuit as a work around.

    Anyway, below you'll find a schematic of a basic "OptoIsolator" (also called an "OptoCoupler") driving the gate of a power MOSFET. I provided links on the schematic for the datasheets for D1 and the 4N33M.

    After drawing this I have reservations about it. OptoCouplers aren't fast devices and MOSFETS like to be turned on and off as fast as possible when used in high current switching applications. A Schmitt Trigger between the coupler output and Q1's gate would speed switching times. I did some googling and found quite a few OptoCouplers with integral schmitt trigger and logic level output but none of those devices are in my Tina library. Besides that issue I have reservations about the turn off time of Q1. Even if the Opto was super fast R3 would slow fall time of Q1.

    This issue sent me in a different direction.. Solid State Relays (SSR). These devices are designed for very high current switching in AC applications. They employ a zero crossing detector that insures that the output is switched on and off when the line crosses through zero. Your wiper motor can be powered by unfiltered DC. IE, mains transformer with a full wave bridge rectifier which I believe will satisfy the zero crossing requirements of an SSR.

    https://en.wikipedia.org/wiki/Solid-state_relay
    https://www.sparkfun.com/products/retired/10636
    https://www.sparkfun.com/products/13015

    Some opinions from some of our members would be welcome.

    Chris

    upload_2017-2-25_9-55-22.png
     
    Last edited: Feb 25, 2017
  16. spyder9

    spyder9

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    Feb 15, 2017
    Thank you for your reply and this schematic
    I understand most of it
    Only question is,what is this element (J1 P1),with no connection between

    And also this ac ssr can be driven by dc current ?
    When i get home in an hour i will try to google some more info about it all and understand it more.

    Ivan
     
  17. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    J1 & P1 are connectors. Yes, they're triggered by low current DC and employ an integral OptoCoupler input. I provided links for SSR descriptions. Later I'll post a block schematic using an SSR in your application.

    Chris
     
  18. spyder9

    spyder9

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    Feb 15, 2017
    Ok,now i get it all
    Gsm transmits signal to ir every second,it is not continious
    At the motor,will it also run every second and not continious ? Or this opto, like PIR has a certain delay before switching off
    Also,what symptoms can occure by having slow optocoupler with fast mosfet request ?
    Ivan
     
    Last edited: Feb 25, 2017
  19. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    In this world the terms "fast" and "slow" are relative to the topic being discussed. When I said OptoCouplers are slow I'm speaking in terms of microseconds vs nanoseconds. When a MOSFET is used to switch a heavy load it's imperative that the Gate - Source voltage (that turns the fet on) transistions from low to high as fast as possible. Likewise we want the Gate - Source voltage to switch from high to low as fast as possible. Remember that power in Watts = E x I. So looking at these plots you should be able to understand why switching a FET on and off as fast as possible is imperative.

    I did some searching on ebay and found some modules that look like they'd fit your requirements with very little DIY on your part. Some employ Optocoupler input and all provide an adjustable hold time.

    http://www.ebay.com/sch/i.html?_odk...lay+board.TRS0&_nkw=time+delay+board&_sacat=0
    http://www.ebay.com/itm/DC-12V-Norm...hash=item35dbc138de:m:mZe9VLHVCi1drd54VrG0tPg
    http://www.ebay.com/itm/DC-24v-High...594734?hash=item2cb523f96e:g:RwgAAOSw5cNYGz~i
    http://www.ebay.com/itm/DC-5V-12V-2...856123?hash=item282b66e7bb:g:7qcAAOSwTuJYnzJO
    http://www.ebay.com/itm/Adjustable-...hash=item2cb000054d:m:m02YwzUT302c1_w9NHPcukQ

    Chris
    upload_2017-2-26_10-52-21.png
     
  20. spyder9

    spyder9

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    Feb 15, 2017
    I'm aware that time difference is not noticable
    But i wasnt able to explain what i asked,now i get it

    So the solution will be that i add this module after the mosfet and before motor connector J1
    Or to put this module instead of FET ?
    Acording to this latest schematic i need this module after the FET
     
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