Arduino Forum

Topics => Science and Measurement => Topic started by: Mimseey on Oct 19, 2019, 01:16 pm

Title: Is OPT101 valid replacement for TSL237?
Post by: Mimseey on Oct 19, 2019, 01:16 pm
Could I use this sensor instead of TSL 237 light to frequency converter? I need to use it to measure absorbance values of aqueous sample. Could somebody explain do both of these sensors work on same principles?

Title: Re: Is OPT101 valid replacement for TSL237?
Post by: 6v6gt on Oct 20, 2019, 02:34 pm
Well, these devices both measure light intensity:

OPT101: http://www.ti.com/lit/ds/symlink/opt101.pdf (http://www.ti.com/lit/ds/symlink/opt101.pdf)

TSL237: https://ams.com/tsl237 (https://ams.com/tsl237)

The difference lies mainly in how they present the light intensity at the output.
The OPT 101 delivers a voltage which increases linearly with intensity.
The TSL237 delivers a frequency (Square wave 50% duty cycle) proportional to the light intensity.

You can work with both using an arduino. The OPT 101 you can read maybe with a voltage divider direct by an analog pin. The TSL237 is a bit more complicated because you have to write code to measure the signal frequency (up to 1Mz which could be around the limit without simple additional hardware such as a frequency divider chip)
Title: Re: Is OPT101 valid replacement for TSL237?
Post by: Mimseey on Oct 20, 2019, 07:27 pm
Thank you a lot!