Wireless Movement Monitor with Timer IC

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In this tutorial, we are making a wireless movement monitor circuit. This circuit is based on a pendulum system and it will monitor large objects and notify you wirelessly from a distance of up to 50 meters to a remote location on an FM receiver. We have used an FM transmitter at the output to broadcast the tone on an FM receiver or radio. The circuit is using two 555 timer ICs.

These ICs are quite common among electronic circuits they are used to provide time delays and oscillations in a circuit. It has three modes of operation, astable, bistable, and monostable multivibrator.

Hardware Components

The following components are required to make Wireless Movement Monitor Circuit

S.no	Component	Value	Qty
1.	Input supply	4.5V-6V	1
2.	Pendulum system	–	1
3.	IC	NE555 Timer	2
4.	Transistor	2N3904	1
5.	Antenna	–	1
6.	Coil	–	1
7.	Resistor	100Ω, 1KΩ, 39KΩ, 10KΩ, 1MΩR, 10KΩR	1, 1, 1, 1, 1, 1
8.	Potentiometer	1MΩ	1
9.	Ceramic Capacitor	0.01µF, 0.1µF, 1nF, 28pF, 2pF, 10nF, 62pF	1
10.	Variable capacitor	TR	1
11.	Electrolytic Capacitor	100µF	1

NE555 IC Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer

2N3904 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3904

Wireless Movement Monitor Circuit

Working Explanation

The operating voltage of this circuit is 4.5 to 6 volts DC. Its working is simple when any movement occurs the pendulum swings and touches the loop which triggers the 555 Timer IC1 for a preset time.
This will now send a high signal to IC2 which will get triggered as well and activates the transmitter circuit. The transmitter circuit needs some tuning initially before using it.

The preset time period of IC1 depends on the 1M variable resistor and the 100uF capacitor. The tone is adjusted through a 1M potentiometer between pins 7 and 8 of the IC. To adjust the volume of the tone we have used a 10K variable resistor. A variable capacitor TR is used for adjusting the FM broadcast frequency of the circuit. The antenna used is a 12-inch wire, to increase distance use an 80 cm antenna.