The project illustrated below helps to find out nearby person or vehicle and make them visible to one another. It can be used in various applications for pedestrians, runners, bicyclists, motorcyclists, vehicles etc.
Most of the time during the night when the roads are badly lit the risk of accidents increases. Sometimes it happens that our vehicle breaks down and we need help. In such conditions this reflector can be used which automatically gets turned ON when it receives light from another vehicle passing nearby. The circuit is based on 555 timer IC and uses a NE555 version of it. The pin diagram of the IC is shown in the image below:
Fig. 1: Pin Diagram Of NE555
The reflector circuit consists of Light dependent resistor (LDR), timer IC (NE555), some bright LED’s and Transistor (BC549) which is used as buffer. In this project 555 timer is configured in oscillatory mode.
When ambient light is dim a potential drop occurs across the light dependent resistor (LDR) below the level set by VR1. Due to this the reset terminal (PIN4) of NE555 goes high to enable the oscillator.
In other words we can say that in the presence of light, the resistance at PIN4 of IC1 is very low. Hence no signal is passed to PIN4 of IC1 so the voltage at pin 4 becomes equal to zero. As a result of this low voltage the circuit remains OFF and in the darkness vice versa occurs so PIN4 of IC1 becomes high and we get the output.