Car Boost Gauge

Discussion in 'The Projects Forum' started by sicktim, Feb 15, 2013.

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  1. sicktim

    Thread Starter New Member

    Nov 23, 2012
    I am having trouble with using a transistor to change the color of the gauge. There are four wires from the boost gauge that control the color (blue, amber, white, green) and there are two for power. If the color wires are connected to the positive (12V), then it changes to that color. I'm trying to write a program using arduino to change the color using 4 outputs and 4 transistors. It seems simple: Using the outputs from arduino, connect them in series with a resistor to the base of the transistor and then the collector to the positive and then the emitters to each of the color wires. When I try this, I cannot get enough current to flow into the color wires. I need about 0.15mA and this is possible by connecting +12V to the base (with resistor). But when I connect the 5V arduino to the base, I can only get 0.10mA and this is nobueno for functionality (it does not work). I even tried without a resistor between arduino and base and can only make 0.10mA. I'm baffled.

    Maybe i'm going about this all wrong, any help or tips would be great.
  2. Wendy


    Mar 24, 2008
    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    Another good forum that shares many of the same membership is . Good luck.
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