CMA ML14s User guide

Brand: CMA

Model: ML14s

Type: User guide

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LIGHTSENSORML14S

USER’SGUIDE

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CENTRE FOR MICROCOMPUTER APPLICATIONS

http://www.cma-science.nl

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2|ML14sLightSensorUser’sGuide

Figure2. Light source dependency, fluorescent

lightissetto‘1’.

Figure 2. The spectral sensitivity of the light

sensor.

Shortdescription

The Light sensor ML14s measures light intensity levels

in3ranges,0.35to22,937lux,1to65,535lux(default),

and1.53to100,487lux.Thisgeneral‐purposesensoris

suitableforindoorandoutdoormeasurementsoflight

intensity.

Thesensorusesaphotodetector,whichis mountedon

thesurface

underaglasswindow.Toprotecttheglass

window the sensor is closed with a plastic cap. The

sensorhasamountingthreadlocatedononesideofthesensor.

The Light sensor is an I2C digital sensor, which gives calibrated values of the

measured quantity. This sensor can only

be connected to special interfaces that

supportI2C digitalsensors like the CMA MoLabinterface. The sensorcableneeded

toconnectthesensortoaninterfaceisnotsuppliedwiththesensor(sensorcables

aresuppliedwithinterfaces).

Sensorspecifications

TheLightsensorML14sisadigitalsensorthatconvertsthemeasuredlightintensity

valuetoa digitalvaluevia16‐bitanalog‐to‐digitalconversion.Theresolutionof the

sensorvariesbetween1lux(samplingrateupto8Hz)and32lux(samplingrateup

to200Hz).The

Lightsensorusesaphoto‐detector,whichissensitivetolightinthe

range of 400 to 840 nm, with the peak sensitivity at a wavelength of 560 nm. The

spectralresponseofthesensorapproximatestheresponseofthehumaneye.

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ML14sLightSensorUser’sGuide|3

Collectingdata

ThisLightsensorworksonlywithspecificinterfaces.Thesensorwillbeautomatically

detected when connected to such an interface. For detailed information about

measurementswithsensorsconsulttheUserManualsoftheinterfaceandtheCoach

6software.

Calibration

TheLightsensorissuppliedwithafactorycalibrationinlux(lx).TheCoach6program

allows selecting the measuring range of the sensor and shifting the sensor

calibrationifneeded.

Suggestedexperiments

TheLightsensorcanbeusedinavarietyof

measurementssuchas:

 Inversesquarelaw.

 Measuringthelightintensitylevelsof

varioussources.

 Studiesoftransparencyofmaterials.

 Studiesoflightreflection.

 Theeffectoflightintensityon

photosynthesis.

 Investigatingratesofreaction.



Weatherstudytomonitorsunriseand

sunsettimes.

 Solarenergystudies.

Luxmeasurement

Lux(Latinfor“light”,symbollx)istheSIunitforilluminance andluminousemittance

i.e. it is used to record the light incident on a surface (striking a surface) or light

emittedfromasurface.Belowaregivenlightintensitiesofexemplarylightsources.

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Illuminanceinlux Lightsource

1 Moonlight

50 60wattbulbatadistanceof1m

100 100wattbulbatadistanceof1m

300‐500 Officelighting

400 Sunriseorsunsetonaclearday

1,000 Overcastday,typicalTVstudiolighting

10,000–25,000 Fulldaylight(notdirectsun)

32,000to130,000 Directsunlight

Figure3. Investigating the light intensity from

a light source as the light sensor is moved

awayfromit‐inversesquarelaw.

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4|ML14sLightSensorUser’sGuide

TechnicalSpecifications

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Sensorkind

Digital

on‐sensordigitalconversion

(upto16‐bitsresolution,communicationviaI2C)

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Measuringrange

1to65,535lx(default)

0.35to22,937lx

1.53to100,487lx

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Resolution

range1to65,535lx(default)

1luxforsamplingfrequencieslowerthan8Hz

32luxforsamplingfrequencieshigherthan8Hz

range0.35to22,937lx

0.35luxforsamplingfrequencieslowerthan8Hz

11.2luxforsamplingfrequencieshigherthan8Hz

range1.53

to100,487lx

1.53luxforsamplingfrequencieslowerthan8Hz

48.96luxforsamplingfrequencieshigherthan8Hz

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Readingtime

120ms(range1to65,535lx)

286ms(range0.35to22,937lx)

65ms(range1.53to100,487lx)

Maximalsamplingrate 200Hzinlowresolutionmode

Spectralrange 400to840nm

Dimensions Housing:32x18x64mm(WxDxH)

Opticalglasswindow:24x30mm

Connection 5‐pinsminijackplug

Warranty:

The Light sensor ML14s is warranted to be free from defects in materials and

workmanshipfora period of12monthsfrom thedate of purchaseprovidedthatit

has been used undernormal laboratory conditions. This warranty does notapplyif

thesensorhasbeendamagedbyaccidentormisuse.

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Note: Thisproductisto beusedforeducationalpurposesonly.Itisnotappropriate

forindustrial,medical,research,orcommercialapplications.   

Rev. 17/11/2011

CMA ML14s User guide

CMA ML14s User guide

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