S e c u r i t y L i g h t E a s t e r E l e c t r o n i c s P r o j e c t Dark Sensor Comparator Monostable Counter Light Brief Design a system that turns on a light when a dark sensor detects darkness than also stays on for two minutes, when it senses light. System Diagram

S e c u r i t y L i g h t E a s t e r E l e c t r o n i c s P r o j e c t Circuit Diagram

S e c u r i t y L i g h t E a s t e r E l e c t r o n i c s P r o j e c t How it Works The Comparator in the centre of the circuit is constantly checking whether the LDR senses that it has become darker than the light level set by two resistors. If it is darker, the Comparator outputs low which triggers the monostable counter to the right of the circuit this then turns on the bulb in the top right of the circuit. If the LDR then senses that it is light again, the bulb stays on while the electricity stored in the charged Capacitor is used up.

L i f t S a f e t y E a s t e r E l e c t r o n i c s P r o j e c t Brief Design a circuit which would be placed in a lift which would stop the lift motor from moving and flash a warning light when more than 8 people stepped into the lift or the total weight of people in the lift exceeded 800kg 1. Weight Sensor Comparator Astable Timer Light, Electromagnetic switch. 2. Pressure Pad Decade Counter Astable Timer Light, Electromagnetic switch. System Diagram

L i f t S a f e t y E a s t e r E l e c t r o n i c s P r o j e c t Circuit Diagram

L i f t S a f e t y E a s t e r E l e c t r o n i c s P r o j e c t How it Works 1. When a person steps onto a pressure pad inside the lift, the decade counter adds one, if eight or more people step onto the lift, it sends a high signal to the astable counter which flashes a red LED and to the latch which stops the lift motor moving. 2. When the amount of resistance of the weight sensor is greater than the resistance set by the comparator (800kg) in the lift, a high signal is sent to the astable counter which flashes a red LED and to the latch which stops the lift motor moving.

M u s e u m A l a r m E a s t e r E l e c t r o n i c s P r o j e c t Brief Design a circuit which would be placed in a museum as an alarm system which would protect a valuable vase. It needs a movement sensor, a temperature sensor and a pressure pad. When the system is activated, it should sound an alarm and lock the doors. The system should be able to be reset via a key-switch. System Diagram 1.Buffer 2.Comparator, buffer. 1. Pressure pad, Movement sensor 2. Temperature sensor. Alarm, Motor for door lock.

M u s e u m A l a r m E a s t e r E l e c t r o n i c s P r o j e c t Circuit Diagram

M u s e u m A l a r m E a s t e r E l e c t r o n i c s P r o j e c t How it Works 1. When the vase is removed from its pressure pad or the movement sensor detects movement in the room a high signal is sent through a buffer and to a motor which locks the doors and a buzzer which sounds an alarm. 2. When the resistance increases past the amount set by the comparator, a high signal is sent through a buffer and to a motor which locks the doors and a buzzer which sounds an alarm.

A n a l o g u e T o D i g t a l C o n v e r t e r E a s t e r E l e c t r o n i c s P r o j e c t