In this tutorial, we are making a project of a movement sensor or detector circuit. To detect the movement of any object this circuit uses a pendulum system. This pendulum system will activate the relay switch when any movement is detected. It can be made easily with two wires by making a loop with one wire and attaching a small weight to another wire as you can see in the circuit diagram, the wires are not supposed to be insulated.
Hardware Components
The following components are required to make a Movement Sensor Alarm Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Input supply DC | 5-15v | 1, 1 |
| 2. | Pendulum system | – | 1 |
| 3. | IC | NE555 Timer | 1 |
| 4. | Piezo Buzzer | – | 1 |
| 5. | Variable Resistor | 1M | 1 |
| 6. | Electrolytic Capacitor | 470uF | 1 |
| 7. | Resistor | 10KΩ | 1 |
| 8. | Ceramic Capacitor | 0.1uF | 1 |
NE555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer
Movement Sensor Alarm Circuit
Working Explanation
The operating voltage of this circuit is 9 to 12 volts DC. The working of this circuit is quite easy to understand. When any movement occurs the pendulum will swing and touch the loop, this will make the transistor Q1 start conducting and activate the timer circuit which is built around the transistor Q2. When the timer circuit activates it will switch on the relay switch.
Any AC/DC appliance such as an alarm or lamp etc. can be connected with a relay switch and it will be activated along with it for a preset time period and automatically deactivate after the time is over. This preset time period depends upon the 470uF electrolytic capacitor connected to this circuit.
The preset time period can be increased or decreased by increasing or decreasing the value of the capacitor. For example, a 100uF capacitor will provide a time period of 15 seconds and a 1000uF will provide a time period of a few minutes.
This circuit can be operated at low voltages such as 5 or 6 volts but you will have to use the relay of the same voltage as the operating voltage.
Applications and Uses
This circuit can be used for multiple purposes such as securing your vehicle’s small or large, or any other large objects.
