Adaptive Lighting System for Automobiles

ADAPTIVE LIGHTING SYSTEM FOR

AUTOMOBILES

Abstract

Our project “Adaptive Lighting System for Automobiles” is a

smart solution for safe and convenient night driving without the

intense dazzling effect and aftermaths. Adaptive Lighting

System for Automobiles needs no manual operation for

switching ON and OFF headlight/down light (Bright/Dim) when

there is a vehicle coming from front at night. It detects itself

whether there is light from the front coming vehicle or not.

When there is light from front coming vehicle, it automatically

switches to the down light and when the vehicle passes it

automatically switch back to headlight. The user can adjust the

light detection sensitivity of this Adaptive Lighting System.

I NTRODUCTION

Adaptive Lighting System for Automobiles needs no manual

operation for switching ON and OFF headlight/downlight when

there is vehicle coming from front at night. It detects itself

weather there is light from front coming vehicle or not. When

there is light from front coming vehicle it automatically

switches to the downlight and when the vehicle passes it

automatically switch back to head light. The sensitiveness of the

Adaptive Lighting System for Automobiles can be adjusted. In

our project we have used four L.E.D for indication of

headlight/downlight but for high power lamp switching one can

connect Relay (electromagnetic switch) at the output of pin 1 of

I.C LM358 Then it will be possible to turn ON/OFF high power

headlight/downlight of the vehicle.

PRINCIPLE: 

This circuit uses a popular timer I.C LM 358. I.C LM358 is

connected as comparator with pin-6 connected with positive rail,

the output goes high (1) when the trigger pin 3 is at lower then

voltage level at pin no 2. Conversely the output goes low (0)

when it is above pin no 2 level. So small change in the voltage

of pin-2 is enough to change the level of output (pin-1) from 1

to 0 and 0 to 1. The output has only two states high and low and

cannot remain in any intermediate stage. It is powered by a 12V

power supply. The circuit is economic in power consumption.

Pin 4 is ground and pin 8 is connected to the positive supply and

pin 1 is grounded.

To detect the present of an object we have used LDR and a

source of light.

LDR is a special type of resistance whose value depends on the

brightness of the light, which is falling on it. It has resistance of

about 1 mega ohm when in total darkness, but a resistance of

only about 5k ohms when brightness illuminated. It responds to

a large part of light spectrum. We have made a potential divider

circuit with LDR and 10K variable resistance connected in

series. We know that voltage is directly proportional to

conductance so low voltage we will get from this divider when

LDR is getting light and high voltage in darkness. This divided

voltage is given to pin 2 of IC LM358. Variable resistance is so

adjusted that it crosses potential of 1/2 in darkness and fall

below 1/2 in light.

Sensitiveness can be adjusted by this variable resistance. As

soon as LDR gets light the voltage of pin 2 drops of the supply

voltage and pin 3 gets high and LED or buzzer that is connected

to the output gets activated.

Component used

1) Voltage Regulator 7812

2) 12 V transformer

3) Diode IN4007

4) LM358

5) Relay

6) Switch

7) General Purpose PCB

8) LED’s

9) Variable Resistance

10) Resistor, capacitors etc.

COMPONENTS

a) Power Supply: For 12v power supply we can use 12 v step

down transformer, bridge rectifier, 12 v regulator.

b) Switch: Any general-purpose switch can be used. Switch is

used as circuit breaker.

c) L.D.R: (Light Depending Resistance) it is a special type of

resistance whose value 

depends on the brightness of light, which is falling on it. It has

resistance of about 1mega ohm when in total darkness, but a

resistance of only about 5k ohms when brightness illuminated. It

responds to a large part of light spectrum.

d) L.E.D: A diode is a component that only allows electricity to

flow one way. It can be thought as a sort of one way street for

electrons. Because of this characteristic, diode are used to

transform or rectify AC voltage into a DC voltage. Diodes

have two connections, an anode and a cathode. The cathode is

the end on the schematic with the point of the triangle pointing

towards a line. In other words, the triangle points toward that

cathode. The anode is, of course, the opposite end. Current

flows from the anode to the cathode. Light emitting diodes, or

LEDs, differ from regular diodes in that when a voltage is

applied, they emit light. 

This light can be red (most common), green, yellow, orange,

blue (not very common), or infa red. LEDs are used as

indicators, transmitters, etc. Most likely, a LED will never burn

out like a regular lamp will and requires many times less

current. Because LEDs act like regular diodes and will form a

short if connected between + and -, a current limiting resistor is

used to prevent that very thing. LEDs may or may not be drawn

with the circle surrounding them.

e) Variable resistance: (Potentiometer) Resistors are one of the

most common electronic components. A resistor is a device that

limits, or resists current. The current limiting ability or

resistance is measured in ohms, represented by the Greek

symbol Omega. Variable resistors (also called potentiometers or

just "pots") are resistors that have a variable resistance. You

adjust the resistance by turning a shaft. This shaft moves a wiper

across the actual resistor element. By changing the amounts of

resistor between the wiper connection and the connection (s) to

the resistor element, you can change the resistance. You will

often see the resistance of resistors written with K

(kilohms) after the number value. This means that there are that

many thousands of ohms. For example, 1K is 1000 ohm, 2K is

2000 ohm, 3.3K is 3300 ohm, etc. You may also see the suffix

M (mega ohms). This simply means million. Resistors are also

rated by their power handling capability. This is the amount of

heat the resistor can take before it is destroyed. The power

capability is measured in W (watts). 

Common wattages for variable resistors are 1/8W, 1/4W, 1/2W

and 1W. Anything of a higher wattage is referred to as a

rheostat.

f) P.C.B: (Printed Circuit Board) with the help of P.C.B it is

easy to assemble circuit with neat and clean end products. P.C.B

is made of bake lite with surface pasted with copper track-

layout. For each components leg, hole is made. Connection pin

is passed through the hole and is soldered.

POWER SUPPLY

The power supply designed for catering a fixed demand

connected in this project. The basic requirement for designing

a power supply is as follows,

1. The voltage levels required for operating the devices is

+5volt. Here +5Volt required for operating microcontroller.

And as well as required for drivers and amplifiers and ir

transmitters and receivers.

2. The current requirement of each device or load must be

added to estimate the final capacity of the power supply.

The power supply always specified with one or multiple

voltage outputs along with a current capacity. As it is estimate

the requirement of power is approximately as follows,

Out Put Voltage = +5Volt, Capacity = 1000mA

The power supply is basically consisting of three sections as

follows,

1. Step down section

2. Rectifier Section

3. Regulator section

Design principle:

There are two methods for designing power supply, the

average value method and peak value method. In case of

small power supply peak value method is quit economical, for

a particular value of DC output the in put AC requirement is

appreciably less. In this method the DC out put is

approximately equal to Vm. A full wave bridge rectifier is

designed using two diodes and the output of the rectifier is

filtered with a low pass filter. The capacitor value is decided

so that it will back up for the voltage and current during the

discharging period of the DC output. In this case the out put

with reference to the center tap of the transformer is taken in

to consideration, though the rectifier designed is a full wave

bridge rectifier but the voltage across the load is a half wave

rectified out put. The Regulator section used here is

configured with a series regulator LM78XX the XX

represents the output voltage and 78 series indicates the

positive voltage regulator 79 series indicates the negative

regulator for power supply. The positive regulator works

satisfactorily between the voltage XX+2 to 40 Volt DC. The

output remains constant within this range of voltage. The

output remains constant within this range of voltage.

Circuit connection: - In this we are using Transformer (12-0-

12) v / 1mA, IC 7805 , diodes IN 4007,LED & resistors.

Here 230V, 50 Hz ac signal is given as input to the primary of

the transformer and the secondary of the transformer is given

to the bridge rectification diode. The positive out put of the

bridge rectifier is given as i/p to the IC regulator (7805)

through capacitor (1000uf/25v). The o/p of the IC regulator

is given to the LED through resistors to act as indicator.

Circuit Explanations: - When ac signal is given to the primary

of the transformer, due to the magnetic effect of the coil

magnetic flux is induced in the coil (primary) and transfer to

the secondary coil of the transformer due to the transformer

action.” Transformer is an electromechanical static device

which transformer electrical energy from one coil to another

without changing its frequency”. Here the diodes are

connected to the two +12volt output of the transformer. The

secondary coil of the transformer is given to the diode circuit

for rectification purposes.

During the +ve cycle of the ac signal the diodes D1 conduct

due to the forward bias of the diodes and diodes D2 does not

conduct due to the reversed bias of the diodes. Similarly

during the –ve cycle of the ac signal the diodes D2 conduct

due to the forward bias of the diodes and the diodes D1 does

not conduct due to reversed bias of the diodes. The output of

the bridge rectifier is not a power dc along with rippled ac is

also present. To overcome this effect, a low pass filter is

connected to the o/p of the diodes (D1 & D2). Which

removes the unwanted ac signal and thus a pure dc is

obtained. Here we need a fixed voltage, that’s for we are

using IC regulators (7805).”Voltage regulation is a circuit that

supplies a constant voltage regardless of changes in load

current.” This IC’s are designed as fixed voltage regulators

and with adequate heat sinking can deliver output current in

excess of 1A. The o/p the full wave rectifier is given as input

to the IC regulator through low pass filter with respect to

GND and thus a fixed o/p is obtained. The o/p of the IC

regulator (7805) is given to the LED for indication purpose

through resistor. Due to the forward bias of the LED, the LED

glows ON state, and the o/p are obtained from the pin no-3.

MICROCONTROLLER

BLOCK DIAGRAM

PD0-PD7PB0-PB7

The microcontroller used here is atmega 16 which has inbuilt adc and counter along with microcontroller. The pin configuration and details are given below.

The ATmega16 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega16 achieves throughputs approaching 1 MIPS per MHz allowing the system designed to optimize power consumption versus processing speed.

The AVR core combines a rich instruction set with 32 general purpose working registers.

All the 32 registers are directly connected to the

Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.

The ATmega16 provides the following features: 16K bytes of In-System Programmable Flash Program memory with Read-While-Write capabilities, 512 bytes EEPROM, 1K byte SRAM, 32 general purpose I/O lines, 32 general purpose working registers, a JTAG interface for Boundary-scan, On-chip Debugging support and programming, three flexible Timer/Counters with compare modes, Internal and External Interrupts, a serial programmable USART, a byte oriented Two-wire Serial Interface, an 8-channel, 10-bit ADC with optional differential input stage with programmable gain (TQFP package only),a programmable Watchdog Timer with

Internal Oscillator, an SPI serial port, and six software selectable power saving modes. The Idle mode stops the CPU while allowing the USART, Two-wire interface, A/D Converter, SRAM, Timer/Counters, SPI port, and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the Oscillator, disabling all other chip functions until the next External Interrupt or Hardware Reset. In Power-save mode, the Asynchronous Timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping.

The ADC Noise Reduction mode stops the CPU and all I/O modules except Asynchronous Timer and ADC, to minimize switching noise during ADC conversions. In Standby mode, the crystal/resonator Oscillator is running while the rest of the device is sleeping.

This allows very fast start-up combined with low-power consumption. In Extended Standby mode, both the main Oscillator and the Asynchronous Timer continue to run.

The device is manufactured using Atmel’s high density non-volatile memory technology. The On-chip ISP Flash allows the program memory to be reprogrammed in-system through an SPI serial interface, by a conventional non-volatile memory programmer, or by an On-chip Boot program running on the AVR core. The boot program can use any interface to download the application program in the Application Flash memory. Software in the Boot Flash section will continue to run while the Application Flash section is updated, providing true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on a monolithic chip, the Atmel ATmega16 is a powerful microcontroller that provides a highly-flexible and cost-effective solution to many embedded control applications.

The ATmega16 AVR is supported with a full suite of program and system development tools including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators, and evaluation kits.

Pin Descriptions

VCC Digital supply voltage.GND Ground.Port A (PA7..PA0) Port A serves as the analog inputs to the A/D Converter.Port A also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used. Port pins can provide internal pull-up resistors (selected for each bit). The Port A output buffers have symmetrical drive characteristics with both high sink and source capability. When pins PA0 to PA7 are used

as inputs and are externally pulled low, they will source current if the internal pull-up resistors are activated. The Port A pins are tri-stated when a reset condition becomes active, even if the clock is not running. Port B (PB7..PB0) Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port B output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port B pins that are externally pulled low will source current if the pull-up resistors are activated. The Port B pins are tri-stated when a resetcondition becomes active, even if the clock is not running.Port B also serves the functions of various special features of the ATmega16 .Port C (PC7..PC0) Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port C output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port C pins that are externally pulled low will source current if the pull-up resistors are activated. The Port C pins are tri-stated when a resetcondition becomes active, even if the clock is not running. If the JTAG interface is enabled, the pull-up resistors on pins PC5(TDI), PC3(TMS) and PC2(TCK) will be activated even if a reset occurs.

Port C also serves the functions of the JTAG interface and other special features of the ATmega16 as listed on page 61.Port D (PD7..PD0) Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port D output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port D pins that are externally pulled low will source current if the pull-up resistors are activated. The Port D pins are tri-stated when a reset condition becomes active, even if the clock is not running. Port D also serves the functions of various special features of the ATmega16.

RESET Reset Input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if the clock is not running. The minimum pulse length is 0.1 vcc. Shorter pulses are not guaranteed to generate a reset.XTAL1 Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.XTAL2 Output from the inverting Oscillator amplifier.AVCC AVCC is the supply voltage pin for Port A and the A/D Converter. It should be externallyconnected to VCC, even if the ADC is not used. If the ADC is used, it should be connectedto VCC through a low-pass filter.AREF AREF is the analog reference pin for the A/D Converter.

Adc

• 10-bit Resolution• 0.5 LSB Integral Non-linearity• ±2 LSB Absolute Accuracy• 13 - 260 μs Conversion Time• Up to 15 kSPS at Maximum Resolution• 8 Multiplexed Single Ended Input Channels• 7 Differential Input Channels• 2 Differential Input Channels with Optional Gain of 10x and 200x(1)• Optional Left adjustment for ADC Result Readout• 0 - VCC ADC Input Voltage Range• Selectable 2.56V ADC Reference Voltage• Free Running or Single Conversion Mode• ADC Start Conversion by Auto Triggering on Interrupt Sources• Interrupt on ADC Conversion Complete• Sleep Mode Noise Canceler

BLOCK DIAGRAM

8051 MICROCONT

ROLLER

RALAY

POWER SUPPLY

LDR

Prominent Features

12V automobile battery powered automatic switching circuit with negligible current consumption in standby mode.

Reliable and weatherproof light sensor module (Cds photocell).

Independent variable control to set the “light detection sensitivity to avoid false triggering caused by the influence of other light sources like streetlights.

Optional selector switch for “Automatic Signaling Mode” (ASM). In this mode, dim/bright control of headlight is in pulsed, i.e. headlight automatically changes to dim level from bright level and vice versa in a rhythmic style (like a signal to the other motorists) when light from the front coming vehicle is detected by the light sensor module.

“Energy Saving Mode” – If the circuit is in active state, by default, headlights automatically goes off when the vehicle enters in a well-lighted area.

Functional Block Diagram

Proposed electrical wiring diagram for existing connection

Proposed electrical wiring diagram for new connection

Schematic Circuit Diagram

Parts list

IC: NE555 – 1

IC Socket 8 Pin – 1 Transistor: BC547 – 1 Diode: 1N4007 – 2 Resistors: 100K Trimpot – 1, 47K 1/4W – 1 ,22K 1/4W –

1 ,10K 1/4W – 1 , 1K 1/4W – 2 Capacitors: 10uF/25V – 1, 100uF/25V – 1 LEDs: 5mm Red /Green – 2 LDR: 20mm Encapsulated Type – 1 Relay: 12VDC SPDT – 1 Switch: SPST Rocker Switch – 2

Working of the circuit

This circuit is built around the popular timer chip NE555 (IC1). Here IC1 is configured as a gated-a stable multivibrator running at a frequency of about 1.5 Hertz (duty cycle 75%), determined by the values of components R1, R3 and C1. The whole circuit can be directly powered from the 12V automobile battery.

When power switch S1 is turned to “on” position, 12VDC supply from the battery is fed to the whole circuit through polarity guard diode 1N4007 (D1). Capacitor C3 (100uF/25V) is a traditional buffer capacitor to improve the circuit stability. Initially, a stable built around IC1 is disabled by the light sensor circuit realized using the 20mm – Light Dependent Resistor (LDR), 100K trimpot (P1) and BC547 (T1) transistor. As a result output (pin 3) of IC1 is at a “low” level, and the 12V electro-magnetic relay (RL1) connected at the output of IC1 is in “off “state. The first LED (LED1) indicates this condition. As per the wiring (+ve supply is routed to headlights through the N/C contacts of RL1), headlights are in now in “on” condition.

However, when a strong light falls on the LDR, IC1 is enabled immediately and as a result its output goes “high” to energize

the relay. Now the down lights are powered by the N/O contacts of the relay and stays in this condition until the light level on LDR is reversed. The second LED (LED2) indicates this condition. Note that, switch for the ASM mode (S2), directly grounds pin 6 and 2 of IC1, when it is in “on” mode and hence the stable function of IC1 is in disabled state. If S2 is in “off” mode, the “ASM” function turns to “on” and this flashes headlights and down lights rapidly, as long as strong light level (from another headlight) is detected by the LDR.

Referance

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Wu Qing, Lei Ling, ChenJianlin, Wang Weifeng. Research on Hardware-in-the Loop Simulation for Advanced Front-lighting System [J]. 2008 Pacific-Asia Workshop on Computational Intelligence and Industrial Applications, 671-675. 

Fang ying-lan, Zhu xiang-bing. The adaptive headlight's function and implementation [J]. The Lighting of China, 2010(7):11-17 

Marc Bodson, John N. Chiasson, Robert T. Novotnak, Ronald B. Rekowski. High-Performance Nonlinear Feedback Control of a Permanent Magnet Step Motor [J]. IEEE Trans. on Control Systems Technology, 1993, 1(1):5-14. 

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