You will be required to design a 'Night Timer' system.night. The
timer should have four 7-segment LEDs i.e. should count up
to 59 minutes 59 seconds in increment of 1 second. Nosferatu
can pause the timer if he spots a beautiful lady while
joyriding. He can also reset the timer any time he wishes to.
You will have to design an electronic system with:
1. Four 7-segment RED LEDs. (his favourite colour)
2. One PAUSE button and one RESET button to pause and reset the timer as needed.
3. Nosferatu starts cycling once it gets appreciably dark. You need to use and configure a Light
Dependent Resistor for that purpose. (Note: Multisim does not make provision for LDRs so to
simulate your design you have to use an Opto-coupler and potentiometer combination to represent
the LDR).
4. You need to use a step-down transformer as the system will have a 230V AC supply (Nosferatu can
generate electrical power from one of his special organ) and the timer should operate on 9V DC.
5. You MUST ONLY use the following components in your design: Power Source, Transformer, Opto-
coupler, Potentiometer, switches, LED Display, Resistors, Capacitors, Transistors, Diodes, Basic logic
gates ICs, Decoders, Timers, Counters and Flip-Flops.
6. You CANNOT use Programmable ICs, Micro-controllers or Multi-Function ICs to design the system.
