Voltage Controller

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

  1. rrowley

    Thread Starter New Member

    Feb 14, 2013
    2
    0
    Hi
    I'd like to build a circuit that would allow me to output 1-10vdc and step through from +1 to +10vdc at one volt increments.Normally I would just use a rotary switch to do this but panel space is limited.The two ideas I've had are..
    1.Use 10 momentary switches eg switch 1 outputs 1v,switch 3 outputs 3v etc.I've seen circuits that give momentary switches latching action but how can I have it so only one button is active at a time and cancels the previous button push?

    2.Have two momentary switches that scroll up and down from 1 to 10v,ideally with a seven segment led display showing 0-9?

    I'd be grateful for any ideas or maybe someone has done this before?
    Thanks
    Rich
     
  2. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    Your first question is merely an exercise in logic design. You'll have a register for each button. When you press a button, a reset signal will be sent of all registers, and a set signal to the register associated with the pressed button. Googling "radio button logic" might give you a littl more info.

    You second question is easily implemented with an up/down counter. One button connects to count up and the other to count down. The output of the counter connects to an D/A converter. There must be some logic between the counter and the D/A converter to make the 1V increments
     
    Last edited: Feb 15, 2013
  3. rrowley

    Thread Starter New Member

    Feb 14, 2013
    2
    0
    Thanks for the info.Now i have something to go on
     
  4. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    I was never satisfied with my answer. Here is something I came up with. If you use a 10-bit A/C converter, then each step is 100/1024 ~=.097V. So, to get 1-V intervals, all 0x11 for each time the pushbutton is exericsed. That gives .097*11 = 1.067V. Use a x 0.945 amplifier/buffer at the output for 1.067*1.945 ~=1.0V intervals. The amplifier can be an opamp with the gain set up vairable resistor. The adder can be an adder IC or a microcontroller.


    EDIT: All my math was based on 1-100V output. Please scale it to your requirements of 1-10V. For example, each step of a 10-bit A/D converter is 10/1024 = .0097, and a 1V output is represented by 110 or 0x6e. This is the value to connect to the "A" input of the adder. Sorry for the confusion.
     
    Last edited: Feb 21, 2013
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