In this tutorial, we are making a project of a simple headlight reminder. It has often happened with all of us that we forget to switch off our car headlights and as a result, the headlights eat the battery fully and the battery gets deep discharged due to which the car does not start until you charge the battery with an external charger. This puts us in a lot of issues and makes us do so many efforts because of our one little mistake.
With this circuit, you can be saved from all this. This circuit is so simple and can be made easily and all the components are easily available, the components used are only two transistors, a melody generator UM66 IC, and a few other discrete components. When you close the ignition switch without closing the headlight switch this circuit will make a melodious alarm to remind you that the headlights are still open until you turn them off.
Hardware Components
The following components are required to make the Car Headlight Reminder Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Transistor | 2N3904, BC548 | 2, 1 |
| 2. | Resistor | 2.2K, 3.3K, 1K | 1, 2, 2 |
| 3. | Electrolytic Capacitor | 0.1µF | 1 |
| 4. | Speaker | 8Ω | 1 |
| 5. | Zener diode | 3V | 1 |
| 6. | IC | UM66 | 1 |
2N3904 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3904
UM66 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of UM66
Car Headlight Reminder Circuit
Working Explanation
This circuit can be connected with the cigarette lighter socket where you will find the three connections as shown in the circuit diagram i.e., dashboard lights, accessory power, and chassis. The working of this circuit is quite simple, if the headlight switch is on after the ignition switch is closed then the circuit will send a signal to the transistors, one of them will switch on the UM66 IC and the others will amplify both input and the output signal. An 8 ohms speaker is used for the output of the melody generator IC, you can either use any small or big speaker of 200 milliwatts to 2 watts as desired.
