Thursday, April 7, 2005

LCD Project Proposal...

So I have this idea for a LCD controller project for my Mac.

  1. Take a USB -> IEEE 1284 parallel printer adapter, open it up and take off the centroncs connector.
  2. Connect it to a parallel character LCD which uses the Hitachi HD44780 controller.
  3. Write a program on the Mac to send data through usb to the LCD.

Why is this any different from all of the other LCD's I have seen?

Well, any LCDs designed for the Mac use a serial connection. May others use serial connections too. This would require a USB -> RS232 adapter . This doesn't seem very elegant considering the project this will be a part of (more to come...). Any that use USB are generally pretty expensive:

http://www.j-works.com/jsb815.html - $65 for just the controller!

http://www.usblcd.de/products/showprod.php4?gr=1&lang=en - 45 euro for the controller.

I imagine I should be able to make this for $10-$20.

potential problems:

  • The IEEE 1284 USB adapters are made for printing, and maybe this won't work with an lcd (I'm not sure this will be a problem).
  • writing to USB devices is a little less obvious to program than writing to serial devices using the darwin IOKit. I sould be able to work this out though. You just can't open up a terminal program and make it work though.
  • Parallel won't let me use a keypad on the device like a serial controller would. But hey, I can use usb, right?

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