Temperatur sensor

[Mikal]

HI!

We are planning to have a student project where student measure ocean temperature and uses the NRF9160DK to send data via MQTT to a broker.

I have completed the fundamental course and it seems like using a i2c sensor i possible.

Do you have any experience or suggestions of whitch sensor to use?

Do you have any experience using a oneWire sensor based on DS18B20?

Br

Mikal Lund

Krokeide Videregående Skole

[Sigurd Hellesvik]

Hi Mikal,

Do you have any experience or suggestions of whitch sensor to use?

We do Nordic specific support, so I can not help with this much. Also because I have not measured the sea before myself.
However, I suggest that you google something like "Arduiono ocean measurement", as this will give the most popular sensor for the task. Especially for educational purposes, having good online resources "er gull verdt" as we say in Norwegian.

Do you have any experience using a oneWire sensor based on DS18B20?

There is a sample in Zephyr for the DS18B20 1-Wire Temperature Sensor, which is a good sign. This sample even has an overlay file for the nRF52840DK, so all you need to do is to add a similar overlay for the nRF9160, and I think it should work.

Was this the info you are looking for?

Mvh,

Sigurd Hellesvik

[Mikal]

Hi Sigurd

We have tried to port the DS18B20 1-Wire Temperature Sensor to the nRF9160DK, but we do not receive any response from the sensor. Is it possible to have a meeting to discuss this? Br Mikal

[Sigurd Hellesvik]

Mikal said:

Does the code: NRF_PSEL(UART_RX, 1, 1) refer to UART1.

Yep, only used if you build for boards with same name as overlay file.

Mikal said:

Does the code: NRF_PSEL(UART_RX, 1, 1) refer to UART1.

Should I use UART0 to use pin P0.00 and P0.01?

These overlay files are not included automatically. They are either included in your CMakeLists.txt or in your build configuration.

I can not see serial_overlay.dtsi anywhere in https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/sensor/ds18b20, so this must be your custom one right?

Mikal said:

Does the code: NRF_PSEL(UART_RX, 1, 1) refer to UART1.

You are setting RX pin to GPIO 1.1. This does not select any UART driver for you. The uart selected is another place in your DTS files, where you refer to the uart1_default pinctrl node.

Mikal said:

Should I use UART0 to use pin P0.00 and P0.01?

The 9160 peripherals can allocate pins as you please, so you can use any UART instance with any pins. Just make sure that the pins match up with the pins you have connected the sensor to on the DK.

[Mikal]

The file serial_overlay.dtsi file is located under board in the github project

[Mikal]

Here is how I have connected the sensor

[Sigurd Hellesvik]

Mikal said:

Why are there both an serial_overlay.dtsi and a arduino_serial.overlay file when they look alike. Since I am using an external sensor is one of them obsolite?

The way I read this is that ardiuino_serial.overlay is there to use with other boards which support this.

However, we wanted to make the sensor sample specifically supported for the nRF52840, in which case boards/nrf52840dk_nrf52840.overlay is included automatically, and it includes boards/serial_overlay.dtsi.

In other words: you do not need to add any of the files manually in your project.

Other than that, I do not understand if you have any questions now. Does this work at your side now, or do you have any troubles still?

[Mikal]

When we understood that 

NRF_PSEL(UART_RX, 0, 1) means connected to P0.01 and

NRF_PSEL(UART_TX, 0, 0) means connected to P0.00 

we received correct response from the sensor