Results tagged “LCD” from The GPSy EV Project

I wanted to hook up a HD44780 LCD panel to my computer to use as a display via the LCD Smartie program.   The HD44780 displays are quite cheap on ebay (~$10) but the dedicated LCD displays that are sold for use with LCD Smartie are quite expensive (~$30).

In the spirit of hacking, I wanted to make my own hookup since I have plenty of HD44780 displays lying around because of my Arduino work.

The LCD Smartie site has a page showing the hookup from the DB25 parallel port on the rear of your computer to an HD44780.

 

lcd44780.gif

However, my cheapo Biostar motherboard doesn't have a rear DB25, only a 25 pin JPRNT1  header (a 2x13 male pin header) on the motherboard itself.  And surprisingly, there isn't any information on the web what the pinout on the JPRNT1 header is.  After much scrounging, I finally found a cached version of a single moribund  site that had the info:

 

ParallelPortHeader.png

Comparing with the DB25 layout, it looks like there is a 1:1 correspondence with the pins on the header and the pins on the cable, with the exception that the JPRNT1 header is 2x13 and not 13+12.  If you look at the header above, the numbers go:

2 4 6 8 10 12 14 16 18 20 22 24 nc
1 3 5 7 9 11 13 15 17 19 21 23 25

 

ParallelPort.gif

Just so that this info doesn't disappear from the ether, I'm keeping things cached here.

Insides of Doc Wattson

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When I was first starting out with the Piaggio conversion, I was monitoring my power consumption using a Doc Wattson / Watt's Up. Good for checking on amp-hours used, voltage, etc.

watts-up.gif

A few weeks into the conversion, I dropped my bike chain on the Doc Wattson and broke the LCD glass. Very annoying -- they should provide a lexan cover on things like this that will get banged around.

I asked the manufacturer if they did repairs and they didn't. I asked them for the spec on the LCD and they said it wasn't divulge-able. They did give me a discount on my second one and I threw the old one in my "crash" bin.

Well, fast forward a few months more and I've been working with STAMPS and PICs and know a bit more about LCD screens -- especially how most 16x2 displays are driven using the same HD44780 IC chip.

Time to open the Doc Wattson up and see what's in it.

More after the jump

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