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Real Time voltmeter

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by CarElectronics, Sep 1, 2002.

  1. CarElectronics

    CarElectronics New Member

    Joined:
    Sep 1, 2002
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    I need to know how to make a circuit for my car to read the voltage off my Oxygen sensor. It puts out a voltage from about 0-1 volts. I want it to be a digital numerical LED display. It really only has to display in hundreths of a volt. I would assume it needs to be of a high resistance so it doesnt "steal" some of the signal going to the cars actual computer. Also it needs to update as quick as possible, realtime if possible. This is my first project and I have basic experience so keep it simple. I know how to make one in the bar display but want a numerical display is there an IC that will hook up to a 2 digit LED?
    Thanks in advance.
    Tim
     
  2. mechie

    mechie New Member

    Joined:
    Sep 4, 2002
    Messages:
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    Location:
    Lincolnshire, England
    Digital Panel Meter - the easy way

    A liquid crystal digital panel meter is available - 0 to 200mV, 3 1/2 digit display, 1000Meg input impedance, 9 to 12v supply.
    A simple 2 resistor divider will give the required range.
    Maplin in the UK (WWW.Maplin.co.uk) sell it for £17. (order code GW01B)
    I bet others (Radio Shack, RadioSpares, etc) also do similar devices?
    :?: This device expects the power supply negative and signal negative to be the same (both 0v) :?:
    :!: A voltage regulator would be a wise idea to protect the meter from a car's battery voltage - this can reach 15v ! :!:
     

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