Mac LCD

Information for using small character LCDs such as the HD44780 with Mac OS X, LCDproc and Growl. And other Apple and Mac USB stuff.

Sunday, January 29, 2006

Command Line Tool Updated

USBLCDWriter Icon

I recompiled the tool to run on earlier versions of Mac OS X. I tested it on 10.2.8 with no problems.

Mac_OS_X_USB_LCD.tgz

Update!

I have posted the updated source for most of the command line tool. It does not include commands specific to the USS720 chip, as I am working on a library for that functionality in the future.

stdinToUSBLCD.c

Thursday, January 5, 2006

LCD Housing

Currently, the USB LCD Kits do not come with any sort of housing or case. However, I have been doing some experimenting and have found a very neat way to house the LCDs: USB LCD Housing

(Note: this procedure can be adapted to work with most character LCDs that you want to mount externally, regardless of the source.)

Parts:

  1. Mac OS X USB LCD Kit
  2. 1593TBK or 1593QBK (slightly deeper) Hammond project box
  3. Small machine screws as long as the project box is deep.
  4. a Decora style light switch plate
  5. short piece of double stick tape
  6. some wire (single strand wire like in cat 5 cable is easiest)

Procedure:

USB printer adapter preparation

  1. Using a sharp knife, carefully cut around the edge of the Belkin USB parallel adapter from the kit. It is easiest to cut into the adapter on the seam on the edge.
  2. Peel back the brown cover and peel away the copper tape and the clear substance that is on the board resembling hot glue.
  3. Cut off the centronics port by scoring the pins where they contact the PCB, and bending it back and forth, or with a small wire cutter.
  4. Remove the USB B port by desoldering the pins and the ground wire and pulling it off the PCB.
  5. Cut the USB cable leaving the amount of cable you need connected to the USB A (rectangular) cable end.
  6. Strip back the rubber insulation and push the shielding to one side. Then strip a small amount of insulation off of each of the 4 wires.

This leaves you with just the PCB from the parallel adapter which is tiny compared to the adapter itself. You may want to cut a cheaper USB cable instead of the nice Belkin one included in the kit.

Project box preparation

  1. On the larger side of the the 2 piece box (we don't need the side with the battery door), clip off the 4 bits of plastic on the inside sides of the box.
  2. Cut off the 2 screw riser posts in near the middle of the box.
  3. cut off the board riser blocks in near the middle of the box
  4. place the decora cover over the box, center it and mark where the 2 holes on the plate should be oriented on the box.
  5. drill the holes through the box.
  6. notch the small end plate on one side where the cord will come through.
USB LCD Back

Assembly

  1. (If you want a strain relief on the USB cable, remember to put it on before you solder.) Solder the four wires and the shield of the USB cable to the small end of the USB adapter PCB. The wire pads are marked with the color of the wire.
  2. Using about 3/4 of an inch of wire , solder the pads of the USB PCB to the rear pads of the LCD following the wiring of the adapter cable included in the kit.
  3. Place some double stick tape on the back of the USB PCB and mount it to the LCD.
  4. Place the LCD in the box and hot glue the end plate of the box in place, aligning your USB cable with the notch you made in the plate.
  5. Using some machine screws, attatch the Decora switch plate by threading them through the box into the small holes drilled earlier.
USB LCD Interior

Conclusions

This project box is perfectly sized to to hold the display, and just deep enough to hold the PCB also. The deeper box is a little better suited to getting everything in there. The Decora switch cover is absolutely the right size for the 16x4 LCD display, and is available in many colors and materials. Most of all, the parts for the housing cost less than $6.00. I have a brushed aluminum plate for my powerbook and a white one for my iBook. You an even get clear switch plates for a hi-tech look.

Pictures to come!