1

Digital Light Meterby

Ak Muhammad Saufi

Final Year Project

Contents1. Objectives of the project2. Introduction3. Implementation of the project4. Schematic Overview5. Programming flowchart6. Testing and Results7. Conclusion8. Recommendation

2

3

1. Objectives of the project• To measure the level of light at a sensor• To display the value of the lux in a qualitative

manner on the LCD• To collect data recorded• To give an idea of the light cycle for duration of

data collected

1.1 Project Timeline

4

PlanningData Gathering

ExecutionTesting

Report Writing

June 2011 July 2011 Sep 2011 Oct 2011 Nov 2011 Nov 2011

Completed

5

2. IntroductionWhat is Digital Light Meter?It measures the control parameters based on the

intensity of the ambient light.

Tool Used;Hardware – Micro controller (Arduino Uno)Software – Programming (Arduino IDE)

6

3.1. Hardware ImplementationMain Components;

16 x 2 LCD Display

Arduino Uno microcontroller

Light Dependent ResistorPrototyping shield

3. Implementation of the project

7

7

Additional Features

3.1. Hardware Implementation

The Data LoggerReal Time Clock (DS1307)

Temperature sensor (TMP32)

8

3.2. Software ImplementationMain Element – Arduino IDE;

9

4. Schematic Overview

10

4.1 The Assembly of the ComponentsBlock Diagram

The Block Diagram of the Digital Light Meter

The Block Diagram of the Data Logger

11

4.2 The Complete Circuitry Board

11

12

5.Programming Flowchart

12

13

6. Testing and ResultsMethods & Steps;Testing on different real environments

- Table lamp- In a refrigerator

Data LoggingPlotting the results

13

Resistance vs Light level (Theory)

14

Linear characteristic on logarithmic graph

Resi

stan

ce o

f LD

R in

kΩ

Light Level in Lux

15

6.1 Test Results (Table Lamp)

• When a brighter light level is directed towards the sensor, the resistance is lower.• When a lower light level is directed towards the sensor, the resistance has risen dramatically

The Temperature sensor being squeezedUntil it warms up.

As the Light meter is shone brightly onto the table lamp.

Light

level (l

ux)

Tem

pera

ture

(F)

16

6.2 Test Results (Refrigerator)

The data logger The 9V battery

17

6.2 Test Results

1818

6.3. Typical Measurement

Results based on using 1kΩ Resistor

• When a brighter light level is directed towards the sensor, the resistance is lower.• When a lower light level is directed towards the sensor, the resistance has risen dramatically

19

7. ConclusionThe results demonstrated that the digital light meter is functioning as per intended design, and meeting the overall project objectives.

The project is successfully implemented, within a timeframe which total cost estimated at $170.00.

Some typical applications of the equipment can be used for monitoring and recording light sensitivity and temperature such as light testing in the factory, home, office, farming, hospital, laboratory and food storage for preservation. It can also be used for trending on condition change for analysis or investigation.

20

8. Areas for Improvement (Recommendation)

- Use a 1kΩ resistor and adding 2kΩ resistor series to it improve much better reading of

lux in bright lights.

- Have more than one sensor (or setups) to collect data from more than one sample

area

- Also, incorporate a temperature sensor to send signal directly to LCD display by using

the microcontroller

Demonstration

21