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Help with a project idea

Discussion in 'General Electronics Discussion' started by nopuk, Mar 6, 2018.

  1. nopuk

    nopuk

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    May 11, 2015
    Hello,
    Purely as a personal project I would like to make the following:

    A board of 50 or so LED's, where the number that light up would depend on the value read in from a data file. Eg
    file={2,4,8}
    output={2 leds, break, 4 leds, break 8 leds}
    move onto next file or just repeat.

    My question how do I go about the above? I am guessing an ardunio is the way to go?

    I have never used ardunio, and was super pleased with myself being able to solder leds and resistors in parallel - thats my current level.

    Any advice on how to even start?
     
  2. LightShow

    LightShow

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    Jun 9, 2016
    do you mean like a scrolling led sign type thing?
     
  3. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The basics of this type of project can be found by learning how to drive a dot-matrix display as per this link:

    https://create.arduino.cc/projecthub/SAnwandter1/programming-8x8-led-matrix-23475a

    Note that this is not a definitive example but just the first of any number of tutorials on how to drive LED displays that I Googled. There will be others with greater detail that you can search out yourself.

    The LED matrix shown above consists of 64 LEDs and you can get them in any colour or even RGB to create full colour displays however....

    If you can learn the principles behind this display driving you can transfer the programming to an LED board of your own that has the appropriate buffers to drive larger LEDs.
     
    LightShow likes this.
  4. nopuk

    nopuk

    18
    0
    May 11, 2015
    @LightShow no just a static x LEDs on for say 2 sec, then y LED's on for 2 sec and so on as it reads the numbers.

    Thanks @kellys_eye so Ardunio is the way to go? does it have memory to store the data I had in mind? where do I start with learning it from the basics?
     
  5. LightShow

    LightShow

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    Jun 9, 2016
    Im with @kellys_eye on this one ;)
     
  6. kellys_eye

    kellys_eye

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    Jun 25, 2010
    You can store the data internally of the Arduino or externally (EEPROM or SD Card if you want), the choice is pretty much your own.

    As with anything that you (or anyone) currently may 'lack understanding' in it will be a process of gradual learning. I would suggest that ALL beginners in Arduino have to go through the 'flashing LED' programming step and you would be no different in this respect. I did this myself some years ago.

    Google any Arduino 'teach-in' course and it will start with the basics, run through LED control and you'll eventually reach a point where you will feel confident enough to proceed on your own.

    You could, of course, find a ready-made solution to your requirement but that will leave you dissatisfied as the knowledge learned from the progress of learning will feel a lot more satisfactory and give you skills to take forward to other projects or even a career.

    Do yourself a favour and take the subject 'seriously' and gain additional skills that could take you anywhere.....
     
  7. BobK

    BobK

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    Jan 5, 2010
    Arduino is one way you could do it. For a beginner, perhaps the most likely way to succeed.

    A matrix like Kelly's eye proposed will have the LEDs not at full brightness, since they will be on only a fraction of the time. You can up the current above the continuous max to compensate, but they will still be less bright that if drive continuously. To drive them continuously you would need additional chips, shift registers, that allow you store the state for 50 LEDs while using only 2 pins from the Arduino.

    Bob
     
  8. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    I am concerned. LEDs are usually soldered in series with current-limiting resistors, almost never in parallel. I say almost because there may be some legitimate circuit somewhere that, for some legitimate reason, requires a resistor to be soldered in parallel with an LED. I've just never seen such a circuit yet.

    An Arduino is not the world's best approach to learning how to program, and you must know how to program to use an Arduino. A personal computer IMHO is the best tool to use to learn how to program. You will need one anyway to develop and download programs to an Arduino.

    So, if you don't already know how to program, install a BASIC language interpreter on your PC and write some practice programs to get the "feel" of how you translate your logical intent into computer instructions. Logical intent is an expression of what you want to DO (light up some LEDs as a function of numbers input to the program, for example) whereas computer instructions, or a program, is a specific way to communicate and execute your logical intention on a computer, of which there are many kinds.

    Programs can be written as abstractions of reality, independent of the hardware on which they execute. Most higher-level languages encourage, even demand, such abstraction. However, where the rubber meets the road, you have to realize your program must accommodate specific hardware, not an abstraction of some hypothetical computer. The Arduino is an excellent choice to learn how to do this. It supports numerous input/output "ports" that you can connect to external hardware such as LEDs or LED drivers. There are numerous "shields" available that mount on top of the Arduino circuit board to extend the I/O capabilities further into the real world. Most shields are supported by an extensive database of application code fragments, called "sketches" in Arduino-speak. You can stitch these code snippets into your programs almost without effort to build your own independent, free-standing, sketch.

    The Arduino uses an ARM microprocessor to execute programs (sketches), but it is programmed in a version of C++ that is compiled and downloaded to non-volatile program memory on the Arduino using your PC as the program's integrated development environment or IDE. Once the program is downloaded to the Arduino, you can disconnect the PC and operate the Arduino as a stand-alone device.

    It has been suggested that you learn how to light and blink the built-in LED that is connected to one of the Arduino I/O ports. This is the Arduino equivalent to the "Hello, World!" printout that many beginners cut their programming teeth on. Next, you can use an external potentiometer to select a variable DC input voltage to be applied to the Arduino's built-in analog-to-digital converter (ADC). Use the potentiometer to (1) vary the frequency of the LED blinks, or (2) vary the brightness of the blinks with pulse-width modulation, all to be accomplished in software by your very own sketch. Depending on how much time you are willing to invest in learning about Arduino, you should be able to complete both tasks in less than a week. Add in a smattering of electrical circuit theory... Ohm's Law, Kirchoff's Laws, analysis of series and parallel circuits and combinations of the two with one, two, or more voltage and/or current sources and you will be well on your way to an exciting adventure in the electronics hobby.
     
  9. BobK

    BobK

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    Jan 5, 2010
    AVR microcontroller, not ARM microprocessor.

    Bob
     
  10. hevans1944

    hevans1944 Hop - AC8NS

    4,258
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    Jun 21, 2012
    Oops. A Senior Moment there. I should have looked it up before posting. Thanks for noticing, Bob.

    So, after a Google search on "arm vs avr microcontroller" I found this to add to my confusion:

    Then I discovered that Microchip has purchased Atmel, so the OP now has a multitude of options available for controlling a mess of LEDs. Microchip is the manufacturer of the PIC series of μPs that I prefer for simple embedded applications, but didn't mention because they are a bit more difficult to program. The Ardunio is closer to plug-and-play.

    However, the point I was trying to make is you have to know how to program to get from soldering wires together to making LEDs light up according to a logical plan. Everyone, please accept my apology for any confusion I might have injected into this thread.
     
    BobK likes this.
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