calibrating sensor values

[ps_anu]

hi..

i am using nrf52832 and a peripheral device .. temperature sensor ,my temperature values are increasing like(0 ,27,75,80...) how to get a approximate value .

i have referred the datasheet ,but i dono how to solve ?

suggest an idea

[Susheel Nuguru]

There is no visible temperature sensor but instead there is a temperature peripheral inside nordic chip that measures the temperature of the chip itself (and not the surroundings of the chip)

Please look at this thread.which says the same thing. 

The resolution of the temperature is in 0.25 C so you need to multiply your raw data with 0.25 to get the value in Celsius. That would be the temperature of the nRF chip and NOT the environment.

[ps_anu]

no i am using max30205 temperature sensor with nrf52382

[Susheel Nuguru]

Not an expert with that sensor, but there are many answered threads related to that sensor here in devzone. For example, this can be useful.

[awneil]

ps_anu said:

i am using max30205

So that's a Maxim product - nothing to do with Nordic!

You need to contact Maxim for support with their products!

Have you checked their documentation - surely, that must cover issues such as calibration?

www.maximintegrated.com/.../MAX30205.html

[ps_anu]

i am getting the output like this , see the pic . i want to print only the raw data , in this pic my raw data is 28 .... give me some idea

[awneil]

ps_anu said:

give me some idea

Use the debugger to step through your code, and see what is happening.

Use an oscilloscope or analyser on I2C signals to verify what is actually happening on the hardware interface.

Check the sensor documentation to check if this is expected behaviour - eg, does it tell you that it takes a few readings to "settle" ... ?

Again, for specific questions about the max30205 itself and its operation you need to contact Maxim for support - it is not a Nordic product.

[ps_anu]

thankyou

[awneil]

awneil said:

Use an oscilloscope or analyser

See this post (it's about SPI, but applies equally to I2C) for some more suggestions:

https://devzone.nordicsemi.com/f/nordic-q-a/41804/unable-to-read-sensor-data-using-spi-communication-_nrf52840/162690#162690

I2C (aka "TWI") equivalent of the SPIdriver mentioned in that thread:

https://www.crowdsupply.com/excamera/i2cdriver