nRF52840 module and SHT21 sensor

[Hannu Hirvonen]

Hello,

Is there someone who has worked recently with nRF52840 and SHT21 (Humidity / Temperature) sensor ? I have to do some basic test for HW and validate that sensor is working properly ? I have seen that over 3 years ago there was some discussion about that. Basic tests I can do without SD. Of course it is nice to see valid temperature and humidity values at least in debugging console (why not in UART also). 

I run twi_scanner SW and it found device 0x40 = 100 0000 = Sensirion SHT21 device. But how to validata that it really works.

Br,

-Hannu-

[Sigurd]

Hi,

A test program that verifies that the temperature and humidity are within valid ranges sounds like a good idea. An extended test could be to run the test program over time, logging the temperature, and see if it stays within the expected temperature range.

[Hannu Hirvonen]

Hello Sigurd,

Problem is that using twi_scanner project I can see device 0x40 = 100 0000 now and then. I'm not sure if problem is in SD or driver or where ? Sometimes it works fine, but sometimes doesn't. Are you familiar with this SHT21 temperature/humidity sensor using I2C / TWI ?

-Hannu-

[awneil]

Hannu Hirvonen said:

I'm not sure if problem is in SD or driver or where ?

Well, as you said in the OP, you could easily eliminate the SD by simply using a project which doesn't have the SD.

Other than that, are you checking for error reports in the code?

Have you looked at what's happening on the I2C lines with an oscilloscope?

[Hannu Hirvonen]

Hello,

Sometimes I can see SHT21 chip on I2C/TWI bus, but typically not ? When I can't see it I get error 0x00008201 = NRF_ERROR_DRV_TWI_ERR_ANACK. Just using twi_scanner example code. Any ideas how to get it working and is there someone who is familiar with this SHT21 chip ?

-Hannu-

[awneil]

Hannu Hirvonen said:

When I can't see it I get error 0x00008201 = NRF_ERROR_DRV_TWI_ERR_ANACK

So have you looked-up what that error means?

Again, have you looked at what's happening on the I2C lines with an oscilloscope?