bicycle back safety light circuit schematic

Description: This circuit is designed to produce a clearly visible light using 13 high-efficiency flashing LEDs arranged in a pseudo-rotating sequence. Its low voltage, low battery drain operation, and compact size make it suitable for mounting on bicycles as a backlight or for use by joggers and walkers. The circuit utilizes IC1, a CMOS version of the 555 integrated circuit, configured as an astable multivibrator that generates a square wave with a 50% duty cycle at approximately 4 Hz frequency.

The circuit operates on a low voltage supply, making it energy-efficient and ideal for portable applications. The 13 LEDs are connected in such a way that they flash in a sequence that simulates rotation, enhancing visibility during low-light conditions. This effect is achieved by controlling the timing of the LEDs through the 555 timer's output, which toggles between high and low states.

The astable multivibrator configuration of the 555 timer is created by connecting resistors and a capacitor to the timing pins. The frequency of the oscillation is determined by the values of these components, specifically R1, R2, and C1. Adjusting these values allows for fine-tuning of the flashing rate, which in this case is set to approximately 4 Hz. The output from the 555 timer drives the LEDs through a transistor or directly, depending on the current requirements of the LEDs.

The circuit's design emphasizes minimal power consumption, making it suitable for battery operation. The use of high-efficiency LEDs ensures that the light output remains bright while keeping the overall power usage low. This characteristic is particularly beneficial for applications where battery life is crucial, such as in portable lighting solutions for outdoor activities.

The compact nature of the circuit enables easy integration into various mounting systems, whether on a bicycle frame or as part of a wearable device for joggers and walkers. Overall, this circuit provides a practical solution for enhancing visibility and safety in low-light environments.This circuit has been designed to provide a clearly visible light, formed by 13 high efficiency flashing LEDs arranged in a pseudo-rotating order. Due to low voltage, low drain battery operation and small size, the device is suitable for mounting on bicycles as a back light, or to put on by jogger/walkers.

IC1 is a CMos version of the 555 IC wired as an astable multivibrator generating a 50% duty-cycle square wave at about 4Hz frequency..