Introduction
We all demand safety everywhere, from home to offices, from banks to museums, from vehicles to our wardrobes we need security. Hence we require an effective alarm that can easily detect even the touch of a person. So, In this tutorial, we are going to make an “IC 555 Based Touch Alarm”. The sensitive Alarm is the safety purpose circuit that gives a warning alert when an intruder enters a home, museum, office, bank, or any other place. It prevents robbery and heists.
Pin Configuration of 555 timer IC
- Pin 1: Connects to the ground
- Pin 2: Trigger pin. It needs one-third of the supply voltage for triggering. It has a high impedance and can work with 1uf.
- Pin 3: Output Pin.
- Pin 4: To reset the circuit. The voltage should be 0.8 or less to reset.
- Pin 5: Control pin.
- Pin 6: Threshold pin. Have high impedance and can work with 0.2uA.
- Pin 7: Discharge.
- Pin 8: Power supply.
Hardware Required
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | IC | NE555 Timer | 1 |
| 2. | Transistor | SL100 | 1 |
| 3. | Buzzer | 9v | 1 |
| 4. | Metal touch plate coin | – | 1 |
| 5. | Potentiometer | 100K | 2 |
| 6. | Capacitor | 47uF, 0.01uF | 2, 1 |
| 7. | Resistor | 100K, 1M | 1, 1 |
| 8. | Battery | 9v | 1 |
Circuit Diagram
Working Explanation
In this IC 555 Based Touch Alarm circuit, we are using a 9V bias supply. Resistor R3, potentiometer R4, and Capacitor C3 are working as timing components. Hence, by varying the potentiometer R4, you can get different timing outputs at the output pin which is pin 3. The transistor SL 100 is working as a switch and therefore the buzzer is connected to the collector of the transistor. R1 resistor and C1 capacitor can change the shape of an output wave, depending on the value of resistor R1. The buzzer will produce different alarm sounds when the touch plate sense.
Application and Uses
- Burglar detection systems.
- Security systems.
