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Salvage LCD display for homebrew GPS clock

Discussion in 'Homebrew and Kit Projects' started by KJ6ZOL, Sep 27, 2018.

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  1. KJ6ZOL

    KJ6ZOL Ham Member QRZ Page

    With all the talk about WWV/H/B going QRT I am taking a stab at building the GPS controlled clock in this PDF:

    http://w8bh.net/avr/clock.pdf

    W8BH used LED displays, which are power hungry, so I decided to swap them for LCD displays from old radio controlled clocks. So when an old SkyScan clock popped up at a thrift store for $3, I grabbed it. After I dismantled it I noted that there only seems to be a single black wire leading from the motherboard to the display, and this wire is labeled GND on the motherboard, strangely enough. There is a 4 wire ribbon leading from what apparently is the radio receiver daughterboard to the motherboard, right next to the black wire. On the motherboard the LCD is labeled "IS15030". Google turns up nothing, and there is no documentation, such as schematics, for this clock. The clock is pretty old-the boards are copyright dated 1999 and 2000. Does anybody have any ideas? Should I just bite the bullet and try to find a NOS display somewhere?
     
  2. KV6O

    KV6O Ham Member QRZ Page

    Looks like it's based on an Arduino. The Hitachi HD44780 is a very popular LCD driver chip that many LCD modules use - Google "arduino lcd" and you'll find a lot. You can pretty easily replace the LED driver code with the LCD driver, experimenting with the LCD on the Arduino will make it easier to understand what is going on, and how to customize code for your needs.

    If you want to use use something that isn't documented, you're going to have to do some reverse engineering - a MUCH bigger task!
     
  3. KJ6ZOL

    KJ6ZOL Ham Member QRZ Page

    Got it. Serves me right for being cheap. :rolleyes: I will go and do some more investigation on Arduino based LCD modules. And the cheap clock goes off to the recycler. :p
     
  4. KF5FEI

    KF5FEI Ham Member QRZ Page

    There are displays, and there are display modules.

    Displays typically have either pins attached to the glass on the perimeter, which are soldered onto the board, or they use zebra strips which make a connection between the LCD glass and the board. There is a driver chip (or chips) on the board which turn on and off the LCD segments.

    Display modules are an LCD display *and* the related driver hardware in one unit. You talk to the module through a number of data lines, and the chip on the display module works out which segments or dots to turn on depending on the characters you want it to display.

    Most Arduino / Stamp / PIC projects use an character LCD module which may be 1, 2 or 4 lines of characters tall, and 8 to 40 characters wide. For the Arduino, the drivers to talk to these displays are easy to include in your code. A standard 2x16 or 2x20 display can be had for as little as $5-10.
     
  5. VE3CGA

    VE3CGA XML Subscriber QRZ Page

  6. KJ6ZOL

    KJ6ZOL Ham Member QRZ Page

    VE3CGA, what I like about the W8BH clock is that it displays UTC in addition to local time. That is what I am looking for.
     

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