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Non Micro-Controller LED Array Control?

Discussion in 'LEDs and Optoelectronics' started by Rory Starkweather, Dec 18, 2014.

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  1. Rory Starkweather

    Rory Starkweather

    77
    7
    Nov 13, 2014
    I've spent two days looking for a way to control the output of an LED array WITHOUT using a micro-controller, and I've had no luck.

    What I want to do is add digital readouts, mainly for voltage and current, to the cases that some of my experiments. I may try using a switch to make the display show more than one value, but probably only one at a time until I have a better idea of what I am doing.

    The problem is that every display I have seen like this lately has been controlled by a micro-controller. I'm not very familiar with micro-controllers yet, but it already seems like a waste of money to use a $30 micro-controller to operate a $1 LED display module.

    I would like to do a cost comparison, but have not been able to find a single design that shows how to build a controller without a micro-controller.

    It seems to me that these designs used to be very common because micr-controllers used to be more expensive.

    What happened to all the old designs?
     
  2. Colin Mitchell

    Colin Mitchell

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    313
    Aug 31, 2014
    By the time you use 3 discrete chips, you could have used a 30 cent micro.
     
    KrisBlueNZ likes this.
  3. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    Well, microcontrollers aren't $30 (unless you want some ultra-fast high-tech device out of a gigabit Ethernet product). Small PIC microcontrollers start around USD 0.50 in 1-up quantities and around USD 0.35 in tube quantities, and those are retail prices. So they're actually cheaper than two or three gate ICs.

    If you want a digital display of voltage, the old way involved a dedicated voltmeter IC such as the Intersil ICL7106: http://www.digikey.com/product-detail/en/ICL7106CPLZ/ICL7106CPLZ-ND/821473

    Many of the devices listed with this Digi-Key filter will be suitable: http://www.digikey.com/product-search/en?pv382=24&pv382=25&pv382=3&pv382=4&pv382=29&FV=fff40027,fff8020a,980006,98001b,980085,9800b3,9800b4&stock=1&quantity=1&pageSize=500 although not all of them are available in THT.

    These ICs can drive LED and/or LCD displays directly, and they may be more accurate than a solution that uses the microcontroller's internal ADC, but they are quite expensive, and cheap microcontrollers are also available with built-in LCD drivers.
     
  4. Colin Mitchell

    Colin Mitchell

    1,416
    313
    Aug 31, 2014
    "If you want a digital display of voltage, the old way involved a dedicated voltmeter IC such as the Intersil ICL7106:"

    You can buy a digital voltmeter on eBay for $3.00
     
    KrisBlueNZ likes this.
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