Lux meter as an obstruction detector

Hello newbie here

I would like to ask for help in our project...
we're planning on using lux meters as an obstruction detector... the idea is that we will use the changes in value of illuminance in an controlled area... that thing is that we need to connect the lux meter into a computer.... an make a program that will track that change...

my problem is that.. the lux meter available in our country doesnt support usb connection... im planning on wiring it to a serial-port.. and maybe a microcontroller and then into a computer.... i really don't have any idea on how to connect it.


i wish somebody could help and share their ideas... thank you.

can you gimme the specs of the lux meter you are using?

LX-104 Digital Light Meter

SPECIFICATION:
• Measurement range scale is from 0.1 ~ 19990 Lux or 0.01 ~ 0.01~1999 FC
• Measuring Range Selection: 200/2000/20000 Lux or 20/200/2000 FC
• Sensor used the Exclusive Photo Diode & Correction Filter
• Data-hold function
• Light Sensor Separate Design for optimum position measure
• Current measurement range scale and illuminated units are displayed on the screen
• Low battery indication
• Offset adjustment
• High accuracy measurement
• Large LCD display and distinct digital data reading
• Power consumption: approximately 2mA
• Response speed: 2.5 times/sec.

is there any communication ports in it already or do we have to make them?

i believe we have to make them...

Is there a communication port of any kind on your meter or only a plug to recharge it ??

it says here that https://www.nunesinstruments.asia/inds/products/detail/flypage/720-lux-meter-lx104?pop=0&sef=hfp its got a usb terminal?
if not, it will be somewhat difficult. we have to disassemble the thing and have to directly connect a Uc to the internal hardware. i think its possible, but if you are not careful you can damage the meter.

btw if i ever i disassemble the thing and able to connect it into the computer... i do still need a micro controller to get it's data isn't it?

our plan is to make a software/program for it so any changes in the illuminance is tracked.... let sayit will show an illuminance vs time graph... slope will tell any obstructions... i'm really hoping it will work...

btw im also open for suggestions, insights and your ideas... i really need help

I can't see that any of the performance features of your Lux meter will serve a purpose for your project. Instead any light sensor with sufficient dynamic range, connected to A/D converter and a computer interface will do the same, e.g. a photo diode or LDR.

As an ultimate solution, a digital ambient light sensor can be used

Over what range do you need to detect obstruction? and what field of view angle? I am thinking of a simpler pulsed IR Rx and Tx. Any voltage available? for detector?
What user interface is necessary? desirable?

actually this is a thesis proposal as of now but we have to implement it as soon as the paper will be approved...
the thing in our paper is that we will use something and think about it "out of the box"... yeah we usually use lux meters in measuring illuminance... but we think we can use it as a obstruction detector in some sort... you're questions are really tough to answer i kinda feel spaced out but we'll think about it...

if we ever manage to connect out little lux meter in the computer we're gonna test it in a small room actually... im not planning to use it for long distance...maybe a confined room since only room lights will be the only thing that would illuminate...

this is how we think it would work
there is a well illuminated room... then a lux meter let's say pointed at the center maybe adjacent to the target...
if you put anything at the center illuminance will change because light would be reflected or absorbed... so any changes in illuminance would tell me there are obstructions...


sorry for my bad english tho...

Check out **broken link removed** Passive Infrared Motion sensors. or PaPIRS for short.
The temperature difference between the target and the surroundings should be superior to 4°C (7.2°F)
Movement speed: 1.0m/s
Target concept is human body (Size: Around 700 x 250mm)
5m or 12m versions.
low cost slow but sensitive to heat motion.

http://pewa.panasonic.com/assets/pcsd/catalog/papirs-ekmc-catalog.pdf

Not so much for Obstruction….. but mainly for Motion sensing.

A couple buddies of mine long ago invented a BOB sensor for food carts. BOB= bottom of the basket.

MY buddy did the PIC code and I invented the IR Interruption pattern recognition. We used unique pulse patterns with TDM methods using IRDA RX 3 pin chips and discrete LED's so that we could sense any path obstructed as small as a resistor wire across a 2m aisle. We used a 2" hole to create the aperture on each side for tunnel vision which resulted in enough spatial isolation to avoid interference and TDM to resolve which emitter path was active and simple decoding to identify the signature pattern of 99% of the shopping cart bottom rail and nose to detect the presence of a cart and tell which direction it was travelling so that we could easily reject false triggering from women's dresses blocking the path by simple pattern matching. THe IRDA built in BPF AGC allowed wide range in distance at the centre freq. to get great SNR.

Lux meters would suffer from a wide range in noise from background illumination variations while the objects move. so SNR gives false positives and true negatives on detection. Whereas our design had a detection error rate greater than we had patience to test,, ( several thousand trials error free)

i think i'd better make my own lux meter i think i would be far much more easier to connect into a computer.