It is a self-made construction of LCD display for a PC.

Elements used:
  • WINSTAR WH2004-TMI-JT REV.C display (4x20 display has white characters on blue background
  • Centronics socket removed from a dead printer HP690C
  • LPT cable
  • HDD tape (16 wires used)
  • transistor BD 135
  • assembly potentiometer 10k (lying)
  • assembly potentiometer 100ohm (lying)
  • 150ohm resistor
  • 1N4148 diode


This version of LCD display for a PC has software backlight control, as a computer often runs at night.

Schematic:



A piece of board was cut using a blade, what facilitated screwing the socket into the housing. Then a piece of the board was desoldered and the display was connected to the socket by 16 wires. Remember to have a proper list of terminals pins. Pins on the plug are numbered symmetrically to the socket.

Using construction of the socket, you can solder cables to „upper terminals”. In the end, potentiometers, transistor, diode and resistor should be soldered.

Unfortunately, location of pins of Centronics socket is different than in DB-25. So you can move the cables from the bottom row of pins to the upper row. Due to the fact, that there are 8 GND cables in the connector, four of them can be connected to one pin from the display. From the PC, they are derived from the socket.
Using these pins, you can supply the display from the PC (from +5V moelex socket).

First activation:
After connecting the display to the PC and turning on the supply, you have to adjust the backlight power. For white LEDs, current can be in range of 30mA. In presented here display, it was set to 20mA (at maximum setting of the potentiometer). You must install port95nt.exe drivers before starting the display. Then adjust the contrast.

Software:
There are few programs, which can be free downloaded. For text dispalys there are: Smartie and jaLCDs (possibility of using system variables and defining your own variables and many other features). You can create your own configuration file which displays all the information you need.

Pictures and more useful information can be found at the original thread.

Link to original thread (useful attachment) – Wyświetlacz LCD do PC