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Need help with making a circuit for a peltier module

Discussion in 'General Electronics Discussion' started by Marshy933, Nov 9, 2017.

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  1. Marshy933

    Marshy933

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    Nov 9, 2017
    hi there i'm doing a project currently and using a peltier module.
    http://cpc.farnell.com/multicomp/mcpe-031-10-13/peltier-cooler-8-8w/dp/SC10911

    That one to be specific, ive never used one before so really need help for making a circuit to use this. I want it to use a push button to make it start to function if possible. i understand i may need something to regulate the temperature too. Hopefully someone has a circuit design i can use for this?
     
  2. kellys_eye

    kellys_eye

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    Jun 25, 2010
    To heat or to cool?

    Either way you need a constant current source where the current chosen is representative of the temperature produced - which itself will be a product of the peltier and the heatsinking attached.
     
  3. Marshy933

    Marshy933

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    Nov 9, 2017

    Hi there, im gonna be using 2 peltiers, one to heat and one to cool
     
  4. 73's de Edd

    73's de Edd

    2,940
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  5. Marshy933

    Marshy933

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    Nov 9, 2017
  6. Chemelec

    Chemelec

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    Jul 12, 2016
    Why such a Low Voltage Peltier?
    3.8 Volts?
    All the ones I use are rated nominal 14.4 volts.
    As needed for Automotive applications.

    Heating verses cooling, Just reverse the polarity.
    But what is your application?

    Yes regulating the Temperature is Good, Especially Important on the HOT Side.
     
  7. Marshy933

    Marshy933

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    Nov 9, 2017
    These are just the ones ive been given, i honestly just need to get it working with a push button so it will heat up/ cool when button is pressed. and stay at a constant temperature
     
  8. Chemelec

    Chemelec

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    Jul 12, 2016
    For Constant Temperature, Would require a Temperature Monitoring Probe and Current Control Circuits.
    NOT EASY with your Proposed Push Button Control.
    What is your Power Source?
     
  9. Marshy933

    Marshy933

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    Nov 9, 2017
    well constant isnt required, but ideally dont want it so hot it would burn you if touched. But power source im not sure about, i saw a thing about using arduino for setting up peltier but comments said it wont supply enough current. Really i need a circuit design i can just follow
     
  10. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    You really need to define what you are trying to DO first before seeking a circuit design.

    A Peltier device moves heat from one surface to the opposite surface, the direction of heat flow depending on the polarity of the current applied to the Peltier device. If you are trying to control the temperature of one of those surfaces, the other surface needs to be attached to a heat sink that can absorb heat from the first surface, or provide heat from ambient environment to the first surface, either way depending on Pelitier heat-pumping action, which will depend on whether the first surface temperature to be regulated is higher or lower than ambient temperature.

    So, presuming you have a Peltier device connected to a "black box" with incoming power and push button on it, what do you expect to happen when you push the button?
     
  11. Marshy933

    Marshy933

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    Nov 9, 2017
    Pretty much im integrating this with haptics for VR. So the user will be touching the peltier to feel the heat or cold while in the VR world. So really i just need the peltier to heat up/ cool and for the user to be able to touch it
     
  12. hevans1944

    hevans1944 Hop - AC8NS

    4,541
    2,116
    Jun 21, 2012
    That simplifies things a lot. You can just run the Peltier "open loop" without any temperature control, choosing a current for heating and another current for cooling. The efficiency of the Peltier is different, depending on which way the heat is flowing, so you will need to determine the two currents by experiment. Since this is part of a VR presentation, you should integrate a touch sensor with the Peltier device so the Peltier device IS the pushbutton.

    The circuit for changing the direction of heat flow can be as simple as a DPDT relay: actuated it applies power to the Peltier device in a direction that causes the touch surface to heat; de-actuated it applies power in a direction that causes the touch surface to cool. A second relay can be used to turn power on and off if desired. An Arduino, or similar microcontroller/micorprocessor, can be easily programmed to turn on and off a MOSFET with logic-level gate actuation for pulse-width modulation of the current supplied to the Peltier device. Setting the duty-cycle in the PWM software routine to zero effectively turns the Peltier device off. Then you choose two other duty-cycles for heating and cooling by trial-and-error, remembering to associate the actuation/de-actuation of the heating/cooling relay with the appropriate duty-cycle. You can also use an H-bridge configuration (Google this) to control the heating direction as well as produce the PWM of the Peltier current.

    Many ways to build a touch sensor integrated with the Peltier device, but that is a separate problem. You might consider capacitance-sensing circuits (there are integrated circuits available for this function) as well as membrane switches.

    Do you have any experience with electrical or electronics circuits and the construction of same? Do you seek a "monkey see, monkey do" solution, such as you might find in an Instructables project?
     
  13. Marshy933

    Marshy933

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    Nov 9, 2017
    I have a little experience but mainly I specialise in software development hence the VR aspect of this. So ideally a simple solution would be perfect, or a circuit diagram i can follow in doing this.
     
  14. Chemelec

    Chemelec

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    Jul 12, 2016
    What are you intending to use as a Power Source for this?
    Battery or power adapter.
    That Module is 3.8 volts, somewhat an odd rating for either of these sources..

    Want to talk, the UK is a free phone call for me.
    For Better Explanations.

    Peltier-1.JPG
     
    Last edited: Nov 12, 2017
  15. Marshy933

    Marshy933

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    Nov 9, 2017
    Hi there sorry for slow reply, been busy with work but ideally a battery as its small. But a call would be perfect, when would suit you?
     
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