The “LCD2LPT with Lirc“ circuit is the compilation of two circuits found on the net on a single board. The first is LCD to LPT interface and the second an IR remote control interface using http://www.lirc.org program.
The main circuit for LCD connection to LPT was modified adding a backlight and contrast control using 4 push buttons. Responsible for the adjustment are the two DS1809 ICs made from Dallas-Maxim semiconductors along with 2 buttons for each adjustment.
IC1 with the use of S1(+, Up) and S2(-, Down) controls the Contrast of LCD and IC2 with the use of S3(+, Up) andS4(- , Down) and the help of transistor T1, controls the backlight intensity.
IC3 is a 7805 regulator that stabilize the power line of the circuit. There is also a filtering capacitor that helps the transient discharge of the circuit preventing any damages to the ICs.
To JP2 you must apply 12V and if you wish you can add a polarity protection diode (1N4007).
For the IR receiver you must read the site http://www.lirc.org. The only thing i have to add up is to remove pin3 during contraction and read the receiver’s IC datasheet to help you out connecting it right.
An adaptor for the LCD is also included so you can use a ribbon cable for the connection with the main circuit.