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Drive output to LEDs

valleytech
valleytech asked
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Last Modified: 2010-04-26
Hi all,
  I have a bread-board and LEDs on it. I don't know how i can drive my program's output to make those LEDs blinking. Could you please tell me
       + What kind of connector to i need to buy in order to connect my bread board to the system ?
       +  Which port can i make that kind of connection?
       + How can i control the LED from my program ?
 Also, i don't know where to start.
   Please let me know in details since i never do any kind of stuff like this. Thanks for your patience.
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Author

Commented:
Could you please move it to the hardware section. Thanks a lot.
PS: what kind of connector do i need to buy?
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Top Expert 2012

Commented:
Are you sure you want to deal with hardware at such a primitive level?  LCD Smartie (http://lcdsmartie.sourceforge.net/) is open source and lets you control an LCD display in a much easier way - unless you're doing this to learn about controlling LED displays and not to actually build something for practical use.

Author

Commented:
 The LEDs in the bread board will just blink. Honestly, i want to learn how to control it by C, C++, or MFC => so i can use LCD Smartie after I understand the concept. Thanks.

  After i buy a RS232, what should i do next? What issue should i focus on software? Thanks.
Simplest way is to use the parallel port, I think you can get up to 13 LEDs working off it if you abuse some of the status and control lines. But 8 would probably be easier. If they're low output LEDs I think you can just drive them straight off the parallel port, high output ones might suck a bit too much and you'd need to use a buffer. Probably best to use a buffer anyway, if you're using the motherboard parallel port.

Author

Commented:
i have 2 bread boards. For each bread board, i have:
    +  4 yellow leds
    +  4 green leds
    + 4 read    leds

=> total i have 24 leds.
  I group them differently. Yellow leds connect to yellow, red ones to red ones...
  So i have 4 power lines totally. One for GROUND, one for YELLOW Leds, one for GREEN leds, and one for RED leds.
  I just wonder i should use serial port or parallel port?  It seems to me that serial port can have enough current to drive all the LEDs.
  Any advise is appreciated.
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Top Expert 2012

Commented:
All the LCD and VFD devices I have seen use the serial port or USB port and draw power from a standard PC molex connector (+12v, +5v).  Since LCD Smartie is open source, you can look at the code to see how it is done, although it is a lot more complex than simply turning on and off LEDs.

Author

Commented:
I just wonder that after i buy RS232 plug, what should i do next in order to use LCD Smartie. I have no idea how i start since this is my first time to work on it.
Could you please tell me step-by-step ? Thanks.
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Commented:
This one is on us!
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Author

Commented:
Thanks lot. I will read it.
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