Beginning Construction
The schematic for the Random Number Generator is shown in figure 2. There is nothing critical about this circuit. You may purchase the kit to build this unit or hardwire the circuit on a prototyping board.
The circuit uses a 16 x 2 LCD display. You should be able to use any 16 x 2 LCD module that has the Hitachi 44780 controller or equivalent (these are pretty common LCD modules). I am not familiar with every LCD module out there, so when connecting a different LCD module that used in this article double check the pin/function on the LCD’s datasheet. Match pin function of the LCD to the schematic.
The PCB simplifies construction, see figure 3. Q1 is the 7805 voltage regulator. Place the component into position. Bend the 7805 so that it lies flat on the board, see figure 4. Then solder into position. Continue to mount and solder the components into position on the PC board.
We substitute a 75-ohm resistor for the resistor marked 1.2K on the pc board. The 10K resistor by the white silkscreen option box on the front of the pc board is NOT mounted to the board. Leave this component space open. Mount and solder the other four 10K resistors and the 4.7K resistor. The 20K pc mounted potentiometer is mounted on he back on the PC board, see figure 5. Mount and solder the 1N914 (D2) diode into position. The two right angle slide switches, Capacitors C1 and C2.
