How do sensors measure data?

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measurement_course
 
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How do sensors measure data?

Post by measurement_course »

Hey guys,

I’m currently part of a project that aims to use an Arduino Uno and three Adafruit sensors to teach students about measuring technology. I would love to include a section about how the sensors convert the environmental conditions to binary data. While I do find information about principles that CAN be used by sensors to register temperature, humidity, pressure and light, I couldn’t find out which sensing method specifically my sensors ARE using.

I use an HDC1080 digital humidity and temperature sensor. I’m guessing that the temperature is measured by a part with an electrical resistance that changes with changing temperature. Is this correct? Is the resistivity increasing (NTC) or decreasing (PTC) with increasing temperature? What material is used? I have a similar question for the humidity sensor. Is capacitive sensing or resistive sensing used to detect the humidity? Are there any more details you can give?

The next sensor I use is a BMP280 barometric pressure and temperature sensor. How are pressure and temperature measured here (on a hardware level)?

Lastly I use a TSL45315 light sensor. I guess it uses a silicon crystal that has a different conductivity depending on the amount of light. Am I right?

I hope someone can answer my questions.

Thanks!

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Re: How do sensors measure data?

Post by adafruit_support_bill »

The datasheet is the place to look. If the sensing technology is not called out in the manufacturer's data sheet, the manufacturer may consider it to be proprietary. Most sensing technologies have been around for decades and are well documented. But individual manufacturers have their own optimizations and refinements - sometimes combining complementary technologies to improve accuracy and/or range.

The BMP280 datasheet says that they are using micro-machined piezoresistive strain gauges to measure pressure.

And the TSL4531 datasheet states that they are using a photodiode array.

The HDC1080 document is less informative. But most low-cost humidity sensors use capacitive sensing.

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Re: How do sensors measure data?

Post by measurement_course »

Thanks a lot for responding so shortly after I posted the question! I'm going to take a closer look at the datasheets.

Edit: I found multiple datasheets online for each of the sensors. Could you maybe post the links to the ones you looked at?

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Re: How do sensors measure data?

Post by adafruit_support_bill »

For Adafruit boards, you can find links to the manufacturer datasheets in the Downloads section of the guides:
https://learn.adafruit.com/adafruit-bmp ... /downloads

For boards from other sources, check the distributor or manufacturer sites.
https://www.mouser.com/datasheet/2/588/ ... 198438.pdf
https://www.ti.com/lit/ds/symlink/hdc1080.pdf

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Re: How do sensors measure data?

Post by measurement_course »

Thanks!

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