Fuel Reserve Indicator For Vehicles

Here is a straightforward circuit for monitoring the gasoline stage in vehicles. It offers an audiovisual indication when the gasoline stage drops alarmingly under the reserve degree, helping you to keep away from working out of petrol on the way. Nowadays autos come with a dash-mounted gasoline gauge meter that point outs the fuel degrees on an analogue display. The ‘reserve’ level is indicated with the help of a pink marking in some vehicles, but the needle motion in the path of the crimson marking is additionally complicated and no longer actual. This circuit displays the fuel tank under the reserve stage and warns thru LED indicators and audible beeps when the chance level is drawing near. 

Circuit diagram :

Fuel Reserve Indicator For Vehicles Circuit Diagram

The gas sensor system includes a tank-mounted waft sensor and a current meter (fuel meter), that are connected in sequence. The go with the flow-driven sensor hooked up to an interior rheostat offers excessive resistance when the tank is empty. When the tank is full, the resistance decreases, permitting extra current to cross in the path of the meter to give a higher studying. The gas monitoring circuit works by sensing the voltage model developed across the meter and prompts the beeper when the fuel tank is nearly empty. Its level A is hooked up to the input terminal of the fuel meter and point B is connected to the body of the car. The circuit consists of an op-amp IC CA3140 (IC1), two 555 timer ICs (IC2 and IC3) and decade depender CD4017 (IC4). 

Op-amp IC CA3140 is wired as a voltage comparator. Its inverting input (pin 2) obtains a reference voltage managed thru VR1. The non-inverting enter (pin 3) obtains a variable voltage tapped from the enter terminal of the fuel meter via resistor R1. When the voltage at pin 3 is better han at pin 2, the output of IC1 goes high and the green LED (LED1) glows. This situation is maintained until the voltage at pin three drops beneath that at pin 2. When this occurs, the output of IC1 swings from high to low, sending a low pulse to the set off pin of the monostable (usually held high by using R3) by manner of C1. The monostable set offs and its output goes high for a predetermined time according to the values of R5 and C2. With the given worths, the ‘on’ time will doubtless be around four minutes. 

The output of IC2 is used to power the astable circuit together with timer 555 (IC3) by implys of diode D2. Oscillations of IC3 are controlled with the help of R6, R7, VR2 and C4. With the given worths, the ‘on’ and ‘off’ time periods are 27 and 18 2nds, respectively. The pulses from IC3 are given to the clock enter (pin 14) of decade depender CD4017 (IC4) and its outputs go excessive one by way of one. When the circuit is swaped on, LED1 and LED2 glow in case your vehicle has adequate petrol within the tank. 

When the gasoline goes below the reserve stage, the output of IC1 goes low, LED1 flips off and a terrible set offing pulse is received at pin 2 of IC2. The output of IC2 goes excessive for round 4 minutes and all via this time frame, clock pin 14 of IC4 obtains the clock pulse (low to high) from the output of IC3. For the first clock pulse, Q0 output of IC4 goes high and the fairway LED (LED2) glows for round 50 2nds. On receiving the 2nd clock pulse, Q1 goes excessive to illuminate the yellow LED (LED3) and sound the buzzer for round forty five 2ds. This audio-visual sign warns you that the vehicle is working out of gasoline. On receiving the 0.33 clock pulse, LED3 and the buzzer go off. There is a niche of around two-and-a-half minutes before Q5 output goes excessive.

By the time Q5 goes excessive and the red LED (LED4) glows, 4 minutes elapse and the ability provide to IC3 is bring to an end. The output state at Q5 will no longer exchange except a low-to-high clock input is obtaind at its pin 14. Thus LED4 will glow constantly together with the beep. The continuous glowing of the pink LED (LED4) and the beep from the buzzer indicate that the car will run out of fuel very shortly. Q6 output of IC4 is related to its reset pin 15 via diode D3. This means that after ‘on’ state of Q5, the count will at all times begin from Q0. Capacitor C5 presents power-on reset to IC4 when switch S1 is closed. The output of IC1 can additionally be related to reset pin of IC4 by means of diode D1 (1N4148). So when your car is refueled above the reserve stage, LED2 glows to point that the tank has enough gas.

IC5 presents regulated 12V DC for right kind functioning of the circuit even when the battery is charged to greater than 12V. The circuit can be assembled on a perforated board. Adjust VR1 till the voltage at pin 2 of IC1 drops to 1.5V. When level A is hooked up to the fuel meter (fuel gauge) terminal that goes to the gasoline sensor, inexperienced LEDs (LED1 and LED2) glow to indicate the traditional gasoline degree. VR2 may additionally be varied to set the ‘on’ time frame of IC3 at round 20 2ds. Enclose the circuit in a small case and mount on the dashboard the use of adhesive tape. The circuit works most effective in automobiles with poor grounding of the physique.

Author : D. Mohan Kumar