how to send temperature values in nrf5840

RE: how to send temperature values in nrf5840

Nivetha — Mon, 31 Jul 2017 11:37:57 GMT

Thanks, everyone. I got it working:)

RE: how to send temperature values in nrf5840

bjorn-spockeli — Mon, 31 Jul 2017 08:49:26 GMT

You should call the ble_hts_measurement_send() function the same way as the battery_level_update function which is called within the battery_level_meas_timeout_handler.

RE: how to send temperature values in nrf5840

endnode — Sat, 29 Jul 2017 08:37:25 GMT

Btw. Ruuvi tag has one variant without external sensors and this is how they work with nRF52 temperature only (see lines 194 and onwards).

RE: how to send temperature values in nrf5840

Knut Auvor Grythe — Sat, 29 Jul 2017 07:23:05 GMT

Note that sd_temp_get blocks until the measurement is complete, approximately 50 μs. I presume that is why it isn't used in the HTS example, because people are more likely to implement an actual HTS using something interrupt driven similar to how the simulated sensor works.

See infocenter.nordicsemi.com/index.jsp for the documentation of sd_temp_get.

RE: how to send temperature values in nrf5840

Nivetha — Thu, 27 Jul 2017 21:05:55 GMT

Thanks knut! Il try with that:)

RE: how to send temperature values in nrf5840

Knut Auvor Grythe — Thu, 27 Jul 2017 18:39:03 GMT

However, the GitHub code I linked to in this answer does fetch the temperature from the chip, so you should be able to modify the HTS example to use that: github.com/.../main.c

RE: how to send temperature values in nrf5840

bjorn-spockeli — Thu, 27 Jul 2017 14:05:13 GMT

If you take a look at the source code in the example you'll see that its a simulated measurement from the hts_sim_measurement() function in main.c

RE: how to send temperature values in nrf5840

Nivetha — Thu, 27 Jul 2017 13:49:17 GMT

Also, what temperature is actually shown in the app while connecting to just nrf52840? Is it the chip's temperature as given in the temperature sensor of nRF52840? Want to confirm and it shows 37-degree Celsius most of the time.

RE: how to send temperature values in nrf5840

bjorn-spockeli — Thu, 27 Jul 2017 11:35:51 GMT

As far as I know there are no plans on adding the optional characteristics or descriptors to the Health Thermometer Service example in the SDK.

RE: how to send temperature values in nrf5840

Nivetha — Thu, 27 Jul 2017 11:29:12 GMT

Very much needed. I think many are trying to use the optional characteristics and to be compliant with the Nordic standard. It would be great if they update the SDK examples with all characteristics.

RE: how to send temperature values in nrf5840

endnode — Thu, 27 Jul 2017 11:24:38 GMT

Hi Bjørn, speaking about these changes: comparing to full BT SIG HTS specification there are more GATT Chars and methods. Even these are optional they seems to be useful. Any plans to update SDK examples to be fully compliant to BT SIG definitions?

RE: how to send temperature values in nrf5840

bjorn-spockeli — Thu, 27 Jul 2017 11:17:48 GMT

If you read the Health Thermometer example description, found here, you'll see that you need to press button 1 to send the indication(which we have changed to notification). If you want to send the temperature periodically you will have to set up an application timer that calls ble_hts_measurement_send().

RE: how to send temperature values in nrf5840

Nivetha — Thu, 27 Jul 2017 11:09:17 GMT

Thanks! Although it displays the temperature. It does not notify every 1 second like the battery status.

RE: how to send temperature values in nrf5840

bjorn-spockeli — Wed, 26 Jul 2017 14:32:51 GMT

You also need to change the following line in ble_hts_measurement_send() in ble_hts.c from

hvx_params.type   = BLE_GATT_HVX_INDICATION;

hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;

RE: how to send temperature values in nrf5840

Nivetha — Wed, 26 Jul 2017 12:27:47 GMT

Thanks! I changed it. But no effect! do I have to disable the indication in the main file or change to notify else where?

RE: how to send temperature values in nrf5840

bjorn-spockeli — Wed, 26 Jul 2017 12:09:08 GMT

Yes, you simply have to modify the following line in hts_measurement_char_add() in ble_hts.c

char_md.char_props.indicate = 1;

char_md.char_props.notify = 1;

RE: how to send temperature values in nrf5840

Nivetha — Wed, 26 Jul 2017 10:40:49 GMT

Thanks. I got it working. Right now, the values are shown as an indication. Is it possible to change it as Notify?

RE: how to send temperature values in nrf5840

endnode — Wed, 26 Jul 2017 08:27:57 GMT

I believe so. Definitely you should dive into function call stack during sending of these values to see where the actual temperature value is coming from.

RE: how to send temperature values in nrf5840

Nivetha — Wed, 26 Jul 2017 08:01:53 GMT

As of now, I used the health thermometer profile and able to check it via the nrF connect app. But in order to transmit the chip's temperature, do I have to modify the health thermometer service or is the functionality inbuilt already?

RE: how to send temperature values in nrf5840

Nivetha — Wed, 26 Jul 2017 07:48:15 GMT

Yes, indeed it will be in connection. I am trying to read the nrf5840 chips' temperature at the central device.

RE: how to send temperature values in nrf5840

Knut Auvor Grythe — Tue, 25 Jul 2017 06:24:58 GMT

The Health Thermometer profile requires to be in a connection. If you're just intending to broadcast the temperature without requiring a connection, there is an old example on Nordic's GitHub page. I recently updated my fork of it to work with SDK 12.3.0: github.com/.../nrf5-ble-app-temp

Disclaimer: I'm not entirely sure if it reads temperatures correctly any more. I'm getting 40°C flat when I try with my pca10001, but I don't think it even has a temperature sensor. I've been planning to modify mine to read from an external, more accurate sensor.

RE: how to send temperature values in nrf5840

Nivetha — Mon, 24 Jul 2017 09:57:10 GMT

HealthThermometer Service Do I have to modify this to send the chip's temperature?

RE: how to send temperature values in nrf5840

endnode — Mon, 24 Jul 2017 09:51:16 GMT

However if you want example of BT SIG GATT Health Thermometer Service implementation on nRF52 then see this in nRF5 SDK. Still you need to embed it into some application (presumably with some GAP Profile),

RE: how to send temperature values in nrf5840

endnode — Mon, 24 Jul 2017 09:48:01 GMT

That's the problem: BT SIG standartize GATT Service but that doesn't mean you are done. You need to handle all other layrs on both sides. Some of them are easy to handle (= stacks are ready made for them) but some need at least minimal control over APIs (which are platform specific) and there it starts to be complex;)

RE: how to send temperature values in nrf5840

endnode — Mon, 24 Jul 2017 09:46:28 GMT

What example exactly are you referring to? There seems to be Heart Rate Monitor example which should contain Thermometer, but that might be too complex and cumbersome unless you have already app on the other side which will understand HRS protocol and data. Otherwise simply use any protocol (like Nordic BLE UART aka NUS examples) and transport temperature value over the link as you need. There is Thermometer in nRF5x MCUs, not super accurate but for first iteration it's enough. See chip specification and SDK how to read it and you are more or less done.