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I estimated I0 by measuring the voltage in complete darkness, and I by measuring the voltage during the measurement.Mind you that this is not completely correct because the LDR will react differently to different wavelengths.
Hello,Thanks for your interest in my project.The circuit is included in the instructable - I have attached it to this message as well. Put the voltmeter between 0V and Output.
I have no idea - that'll depend on the rest of your experimental setup. I can't give you any application-related information unfortunately.
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That will depend on the clarity and absorbance of the product - you'll have to do some trial-and-error.
Hi there, The voltages needed are mentioned on the schematics: 5 V for the Arduino, 5 - 30 V for the stepper (depending on the stepper), 9 V for the opamp circuit.Absorbance is dimensionless - so it has no unit.In the paragraph "Driving the stepper" I explain how to connect the pushbuttons: "[A]dd pushbuttons by connecting one leg of a 2k2 resistor (pull-down resistor) to ground, connect the other leg to one leg of the pushbutton AND to a digital input on the Arduino.Then, connect the other leg of the pushbutton to +5V from the Arduino."Your calculation seems correct, but as mentioned before it's not perfect because the voltages might not relate 1-on-1 with the light intensity.
By the way, take a look here: https://eic.rsc.org/feature/build-your-own-spectro... for an alternative way of calculating the absorbance that probably is more accurate: I/I0 = (Vsample - Vzero)/(Vsolvent - Vzero)where Vzero is the reading in total darkness, Vsample is the reading through the sample and Vsolvent is the reading of the blank solvent.
I don't. I just take a blank voltage reading (i.e. without the sample) at every wavelength I want to use, add the sample, take another set of readings at the same wavelengths you collected the blanks, and enter those values in the Lamber-Beer formula.It might not be 100% correct, but certainly usable.
Nice work! Glad I was able to inspire you :)
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