Automotive Voltage Monitoring Circuit
Created: Nov 03, 2014
No description available.
This project is a monitoring device that significantly measures the battery of a certain automobile to warn the users pertaining the status of the battery. This system may eliminate future vehicular accidents due to low battery supply. The device uses PIC12F683 microcontroller that has six I/O pins with individual direction control. In addition, it has precision internal oscillator with selectable frequency range of 8MHz to 125kHz. Moreover, the microcontroller contains a 10-bit internal Analogue to Digital Converter (ADC) that compares the voltage on the AN2 input (Pin 5) with a reference voltage.
The PIC12F683 microcontroller that is programmed with firmware measures the vehicle supply voltage using an Analog to Digital Converter (ADC) and compares it to a set of voltage points, activating the bi-color LED to alert the rider when the voltage goes outside the expected normal operating range. The vehicle supply voltage feeds the LM2931AC-5.0, Low Drop Out (LDO) voltage regulator IC to power the microcontroller. This part is designed for use in automotive applications and can withstand load dumps and reverse transient. Diode D1 protects the circuit from accidental reverse polarity of the input supply voltage. Furthermore, capacitors C2 and C3 are required to stabilize the regulator as per the datasheet for the device. The design uses a 47µF capacitor for C3, but a 22µF part can also be used.
Automotive voltage monitoring aims to provide the rider with an early warning if a fault is detected in the battery/charging system. It is done by connecting the electrical supply on the bike and continually measuring the voltage. If the measured voltage falls to the programmed set points, the device will alert the rider with an LED. The design can be applied to cars as well as motorbikes and could also be used for other voltage monitoring applications.