Thermistor with nRF 52840

RE: Thermistor with nRF 52840

Simon — Thu, 09 Jan 2020 00:32:43 GMT

Here is one solution:

Set the reference to VDD/4
Set the gain to 1/4
The input range will then be (VDD/4)/(1/4) = VDD, as described in the infocenter
Then set Vs to VDD, which will make it equal to adcMax (=1024 if 10 bit resolution)
Then you can read the input on Vo, where a reading of 1024 corresponds to VDD, 1024/2 corresponds to VDD/2 and so on...

Best regards,

Simon

RE: Thermistor with nRF 52840

Sundar_santhanam@1998 — Mon, 06 Jan 2020 10:05:18 GMT

My idea is just to connect thermistor with nrf. I just wanted to know how to get accurate results in degree celcius , the formula to calculate thermistor resistance involves adc values , my biggest problem is my adc reference voltage and my source voltage to the thermistor are different . Pls help me solve this issue

RE: Thermistor with nRF 52840

Simon — Fri, 03 Jan 2020 19:43:09 GMT

I am sorry for the delay. Lately, a huge portion of the support team has been on Christmas vacation. Most of the staff will be back 6 of January 2020 and you can be sure to get an answer shortly after that.

Best regards,

Simon

RE: Thermistor with nRF 52840

Sundar_santhanam@1998 — Fri, 27 Dec 2019 15:10:15 GMT

Is it possible to have a reference voltage of 5 Volts and how? Because as of now the ADC reference voltage is 3.6V and the source voltage to the thermistor is 5V ? Even if I give 5V to the Vdd to make it as a reference voltage , it may damage the board. So my source voltage to the sensor and my adc reference voltage are not the same . what can I do in this case?

RE: Thermistor with nRF 52840

Simon — Fri, 27 Dec 2019 15:01:33 GMT

Check out the section Reference voltage and gain settings in the infocenter on how to change the reference voltage for SAADC. If you want me to go more into details about anything please ask.

These cases may also be helpful:

Best regards,

Simon