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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 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.
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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