The microcontroller (MCU)-based automatic turn signal system for bikes that is on the market is expensive and hard to program. Here is a circuit that is easy to build and doesn't cost much. The circuit is used to tell a bike or two-wheeler to turn left or right. There must be two identical circuits, one for the left and one for the right. The circuit is made up of an ADXL335 accelerometer sensor, a voltage regulator 7805 (IC1), an LM393 comparator IC (IC2), two NE555 timer ICs (IC3 and IC4), and a few other parts. ADXL335 is a small, thin, low-power, 3-axis (X, Y, and Z) accelerometer with signal-conditioned voltage outputs. It can measure acceleration in the X, Y, and Z directions. In this project, only the Y direction of the ADXL335 is used. The device has a full-scale range of at least 3 volts and can measure acceleration. It can measure

both static accelerations, like the force of gravity, and dynamic acceleration, like the force of motion, shock, or vibration. Circuit diagram of bike turning signal system Dual comparator LM393 is an IC with 8 pins. Pins 1, 2, and 3 make up one comparator, and pins 5, 6, and 7 make up another. The two comparators are used to watch for signals from the left turn and right turn indicators. We use two NE555 timer ICs (IC3 and IC4) set up as a monostable multivibrator, one for the left signal and one for the right signal. IC voltage regulator is used to turn a 9V-12V battery into +5V DC (IC1). Left signal When the bike handle is turned to the left, a voltage between 1.2V and 2.6V is sent as a tilt angle output. The pin 2 of IC2 is connected to the Y signal from the ADXL335 sensor, and the pin 3 is connected to the preset signal (VR1). The left tilt angle signal

comes out of pin 1 of IC2. Use preset to set the reference voltage to 2.2V at pin 3. (VR1). At first, when the bike handle is turned 90 degrees to the right, the voltage at pin 3 of the comparator will be 2.2V and the voltage at pin 2 will be about 2V. So, the output of the comparator will be high (5V). Pin 2 of IC3 gets this high output signal. Because of this, IC3 won't be able to do much. When the bike handle is turned to the left, IC2's pin 2 will have 2.6V. This means that pin 1 has a low output. The low output signal is linked to IC3's pin 2, which is a trigger. The high signal at pin 3 of IC3 is caused by the low signal at pin 2. When transistor T1 works, LED1 lights up. The width of a pulse made by monostable IC3 is given by the following equation: t=1.1×R2×C4 seconds Right signal When the bike handle moves to the right, it sends a voltage of 2.6V to 1.2V as a tilt angle output (decreases from high to low). Pin 6 of IC2 is connected to the preset (VR2), and pin 5 is connected to the Y signal from the ADXL335 sensor. VR2 is used to set the voltage reference at the inverting terminal to 1.6V. At first, when the bike handle turns 90 degrees, there will be 1.6V at pin 6 and 2V at pin 5. This means that the output of the comparator will be high (5V). This output goes to IC4's pin 2, which makes its pin 3 output low.

t=1.1×R3×C7 seconds When the bike handle is turned to the right, 1.2V will be at pin 5 of IC2. This is less than pin 6's reference voltage of 1.6V. This turns pin 7 of IC3 into a low output. When the output is low, monostable multi-vibrator IC4 starts to vibrate. This causes pin 3 of IC4's output to be high, transistor T2 to conduct, and LED2 to light up.