user Electronics Engineer

city Innovuze Solution Inc.

  • Safety Tail Light

  • Created: Jul 11, 2016

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When vehicles were first invented, the only light it has was for forward vision. At that time, there are few vehicles, so communications to other vehicles are not that important. The rapid increase of vehicles raises the need of a way of communicating other vehicles. Thus, the lighting system of vehicles is made. One of this is the tail light. The tail lights are colored red for it associates with stop, danger or alarm. Tail light are not only used in vehicles but also in bicycles. The tail lights in bicycle how ever are usually taken for granted since people think it just a bike and usually ridden at the side of the road. Unlike the headlight, which can light up the area in front of you, which clearly needed at night. The lack of emphasis of the use of the tail lights and the cost cause it to be taken for granted, thinking that the headlight will be enough. The tail light is used to increase the cyclist visibility to other vehicles and motion approximation of the vehicle behind. This can aid in the visibility of the user from other vehicles on the road. The designed circuit is a tail light that uses the QBLP670D-R-ND LEDs in a pseudo-rotating order.

The LEDs are arranged (see LED Arrangement) in an alternate flashing of two groups of LEDs to have a pseudo-rotating appearance. This is done using two CMOS 555 IC to drive the two groups of LEDs separately; U1 is used as an astable multivirator to drive L1-L6 and U2 as an Schmitt trigger inverter to drive L7-L12. Connecting L1-L6 between pin OUT and VDD in U1 drives the LEDs in a sinking operation, when pin OUT is LOW the LED turns ON. While U2 as an Schmitt trigger inverter operates alternately with U1 turning L7-12 opposite to L1-L6. The C2 provides the timing for the U2 to operate oppositely to U1. The L13 is permanently ON in the center. This alternate flashing gives a rotating effect to the LEDs. The LEDs must be placed in a retro reflector to get the most visibility and reflection.

The road traffic safety is important to prevent accidents on road users including pedestrians, cyclists, motorist, and passengers. The safety tail light is applicable to cyclist, motorist and joggers that use the road for added visibility. Having a full gear of protection might be costly but medical cost is much more costly.



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