Final Project - Fabux Meter, Light intensity measuring device

Objective

To measure light intensity of various lamps and make analysis for energy consumption in lumens. The following information will help to anyone to make LUX meter. Overall it was learning experience for me.

You can know more about LUX or lumens concept here LUX meter

Introduction

I made this project to measure light intensity in digital format. Main purpose of my Lux meter kit is to teach students about light in experimental way. They will able to make their own lux meter.
It will teach them about light and also to give them various activities. These activities will be connected to their curricular area.
Device made as a project is really easy to understand and helpful for everyone It will also find applications in Poly house and poultry farmers

Every one use light but few of us know about intensity. We understand lamps but we can't answer questions about intensity of light.
In Vigyan Ashram we made LED lamps of various wattages but it could not be sufficient to know how much output we get from lamp and same training we provide in schools. So idea is to make LED lamp kit with LUX meter. So student also know about light intensity and they can describe terms to every one with simple small device.

This device is also useful for Farmers of poultry, polyhouse business to get proper lamps with required energy consumption

Trials

Before making this device in digital way (with microcontroller) I have checked couple of circuits like first trial. I put 10 LED and check intensity with number of LED glow. In second trial I have use 10k ohm resistor, LDR and variable pot, 9V DC supply and LED. Finally I decided to make LUX meter circuit as per below.

The above circuit can describe value of intensity of the light being produced by the lamps that we make (at Vigyan Ashram) by measuring voltage drop.

For Fab Academy Final Project I am designing LED lamp kit with LUX meter which measure light units in Digital form.

Processes Covered

I made final project for calculation light intensity with different processes learnt in fab academy shown below. Including electronics design, 2D and 3D design, computer controlled cutting.

Electronic Design and fabrication

In electronic design I did my board during Input Devices and Output devices assignments.

Circuit includes micro controller(ATTINY 44) used for the implementation of ADC and other calculations of light intensity and interface with LDR and LCD display. Input device is a sensor system based on LDR to detect changes in light intensity in analog form. So it outputs a voltage from 0 (darkness) to 5 V. Output device (LCD - to display the light intensity that was measured by the system, in units such as Lumen)

The function is the board reads LDR sensor output voltage whick is internally converted in the ADC of micro controller to a number from 0 to 255. Then some calculations are made in the microcontroller to convert voltage to lux intensity. These calculations are obtained from LDR datasheet. After that the result in displayed in a 16x2 LCD screen.

I did schematic design in Eagle software, Schematic file making is an easy task for me. But create board file was so much hard and challenging. It tooks 3-4hrs completing.

After milling board file on Modela machine, the most hard thing I did is SMD components soldering. Before Fab Academy I never did SMD soldering. I did soldering with general PCB but not SMD. My speed for SMD components soldering during fab academy was min.2hrs max.5hrs.

Above you can see image of the board i Did for final project. Later I had to manually cut the board because I did not cut the FR1 board with the roland modela.

Embeded Program

Embeded program is essential part in electronic fabrication. In embedded program I study Datasheets for microcontroller, LDR and LCD screen datasheet help for making code and schematic file making in eagle. Pin connection and write code very critical but interesting part.

I used Arduino IDE to make the code. The code is a mix of Input Devices and Output devices assignments but also includes algorithm to convert analog voltage from LDR sensor to lux intensity. This algorithm was implemented by reading the datasheet of the LDR sensor. I sucessful did code and shows reading of light intensity. Please see embedded video at the bottom.

After programming board i.e LCD start showing results which sense by LDR
and start showing light intensity value in terms of digits

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3D Design

Before Fab Academy I could do 2d design in Autodesk but 3D designing was a learning for me. I have checked some opensource software for 3d design and then chose TinkerCAD software. But also I make same design in Blender software (see Computer aided design week). I have design LUX meter casing on it.

3D Printing

I wished to print on 3D printer but assembly tooks 6hrs continue to print. I try to print but because of power issue machine got stop after 60% complete or 25% complete and again start from zero. So I feel it was waste of material and time too. Then I decided to cut LUX meter casing on laser cutter using 2D design.

2D Design

2D design of the case was made in combination of Autodesk 123d design software and Inkscape. Inkscape is easy software for 2D design assembly.

Computer control cutting

Laser machine we have in Vigyan Ashram FAB LAB since 2002 and I have good commond on laser machine. So I took design in Inksape and print my file on laser cutter machine. I have done several versions of the box with different materials and sizes until I decided for dark acrilic.

Laser machine is Epilog Laser Mini. Material used for final version is dark acrilic 3 mm. I did not write down laser settings for cutting but these are pretty standard and can be found elsewhere.

Benifits

1)Now I am able to package it as a kit for schools in my network. I am also planning to encourage project to make its use in various situation like polyhouses, use of solar gadgets etc.

2)I want to make this gadget for school children to teach them about light intensity. This D-I-Y kit will also be a good exercise for practicing soldering / programming / sensors and casing design.

3)I have made circuit less complex. I have also used simple LDR as sensor It is very cheap and locally available.

4)The program written for the circuit is very simple. Its only of few lines and can easily explain to children.

5)I have callibrated using datasheet procedure and compared it with commercially available LUX meter and found it to be sufficiently accurate. Which have been little bit difference in intensity min. 7lux and max14-20LUX

6)I have also worked on making D-I-Y instructions so that it can be integrated in our school assignments.

7)In a 10x10x10 (ft) room, would this lamp be able to deliver light with enough intensity so as to read", such a lux meter will help out to identify the answer.


8)We can differentiate LED lamp and ordinary lamp consumption etc.

9)Eventually, this may result into an technically enriched feature list of our LED lamps.

10)This project is more about Laboratory Test/Measurement equipment.

I write more about LUX meter in detail last three assignments

Presentation Slide

Final Version

Final project Video

Download files

Schematic Design Click here.

Final code is hereOriginal code

2D design in Inkscape.2D design file