NRF52840 Thread example power down 10 mins after USB disconnect

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Robert Lubos — Wed, 13 Sep 2017 06:44:57 GMT

I meant DFU example from Thread SDK. You can find it in <INSTALL_FOLDER>\examples\thread\experimental\dfu\client. It uses a copy of IOT CoAP, ported for OpenThread, which is located in <INSTALL_FOLDER>\examples\thread\experimental\dfu\coap. The example itself does not use observe feature though, but you can check the documentation to see how to use it. Optionally, there is an example in IOT SDK (Observer Client) that uses observer feature, so you can use is as a reference for CoAP code. Keep in mind though that IOT SDK examples does not use Thread.

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Tue, 12 Sep 2017 16:02:07 GMT

Thanks for clarifying that. I couldn't find any DFU example in the IOT SDK. The only place i found it was <INSTALL_FOLDER>\examples\iot\tftp\dfu. In the normal SDK, there is a dfu example but no IOT CoAP. Did you mean this example ? <INSTALL_FOLDER>\examples\iot\coap\ipv6\client_observe ?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Tue, 12 Sep 2017 15:43:41 GMT

Setting poll period to 500 ms after just after sending DNS request solved it! Thanks!

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Robert Lubos — Mon, 11 Sep 2017 10:58:48 GMT

Hi, my guess is that there is a mismatch between SED data poll period and DNS query timeout. The poll period is a time between consecutive polls for the data from SED to the parent. If the DNS query timeout is lower than the poll period, the query will fail before SED would even attempt to get the response (which will happen for default value of poll period). What you can try to do is to lower the pool period just after sending the DNS request, the same way we do in Thread MTD CoAP Client before sending CoAP requests: otLinkSetPollPeriod(m_app.p_ot_instance, DNS_POLL_PERIOD);. Just set the DNS_POLL_PERIOD to some reasonable value (default DNS response timeout is 3000 ms, so setting poll period to 500 ms should be fine).

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Robert Lubos — Mon, 11 Sep 2017 10:45:38 GMT

Hi, Unforunately the observer feature is not present in OpenThread's CoAP implementation. Althought there is an API to add "Observe" option to the header, there is no mechanism to handle Observe responses from the server. And just FYI, the aObserve paramter is the value of the Observe option, For more information about this mechanism, please refer to RFC 7641. An option to use the Observe mechanism is to use different CoAP implementation, for example the IoT CoAP that we use in the DFU example (you can find it inside DFU example folder in the recent release). Unfortunately there is no Thread example that demonstrates the use of it, but you can refer to the documentation: infocenter.nordicsemi.com/.../lib_iot_coap_addon_observe.html

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Fri, 08 Sep 2017 07:37:29 GMT

Thanks for the information! So the Cloud COAP client example in the Thread SDK is by default setup to assign router roles to nodes? I saw in the MTD COAP client some lines of code to make a node sleepy end deivce:

 otLinkModeConfig mode;
    memset(&mode, 0, sizeof(mode));
    mode.mRxOnWhenIdle       = false	; // Join network as SED.
    mode.mSecureDataRequests = true;
    assert(otThreadSetLinkMode(p_instance, mode) == OT_ERROR_NONE);

However, when I try to do this in the Cloud COAP client example, hostname resolution always fails. So I'm assuming that sleepy end devices do not do any hostname resolution themselves, but depend on the router?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Krzysztof Loska — Thu, 07 Sep 2017 21:22:10 GMT

Hi,

Thread Routers are not meant to be baterry-powered devices. Routers have their radio turned on and listening all the time when not transmitting. If you need energy optimization you have to use Thread Sleepy End Device role.

This new website is an official place which documents OpenThread project but it also includes very good guides on Thread itself e.g. about node roles and types.

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Thu, 07 Sep 2017 09:22:11 GMT

Thanks for checking. An update from my side - I managed to get a bit further in receiving value on the NRF52840. Basically I use otCoapHeaderInit(&header, OT_COAP_TYPE_NON_CONFIRMABLE, OT_COAP_CODE_GET); to create a message and send that using otCoapSendRequest(p_instance, p_request, &message_info, cloud_data_request_callback, p_instance);. Here, cloud_data_request_callback is the callback function that is executed when the cloud responds with data. I execute this on Button press 3, which works, the cloud returns the JSON string for the requested resource. However, this is the NRF52 kind of polling. Instead, I would like the callback function to be executed when the value on the cloud is changed. For that, I checked and saw there is an "observor" option that can be set using otCoapHeaderAppendObserveOption. In this function, I don't understand the second parameter aObserve Observe field value. I tried various values but they don't work. So it would be great if you could check with the developers about this issue!

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Petter Myhre — Thu, 07 Sep 2017 09:06:23 GMT

I'm not aware of such an example. I'm not sure if it is trivial or not. If you want me to, I can check with the developers if they see any problem with implementing a "cloud coap server"?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Wed, 06 Sep 2017 14:46:47 GMT

Thanks, I'll have a look at that! Can I ask another question about the same Thread Cloud Coap client example? Basically, the example sends data to thethings.io cloud when I press button 1 and 2. I now want to establish communication in the other direction. So, have a button widget in the things dashboard which when pressed sends a value to the NRF52840. Could you tell me if there is some example available about how to do this?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Petter Myhre — Wed, 06 Sep 2017 14:41:15 GMT

I haven't actually tried myself, but the Thread MTD CoAP Client example should be of interest.

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Wed, 06 Sep 2017 14:38:06 GMT

Right now the roles are automatically assigned. I have a network of three NRF52840s, where one of them is a NCP attached to Raspberry Pi and the others are nodes. When a node is joined, I can see in the Thread Topology Manager that it is a end node initially, but after a few seconds becomes a router. Making the node a sleepy end device is a good idea - could you tell me how I can force a node to become a sleepy end device? Some changes in the code?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Petter Myhre — Wed, 06 Sep 2017 13:49:36 GMT

Strange. Could it be that you are draining too much current from the battery, but I'm not sure if there is anything special happening after 10 minutes. Is it exactly ten minutes? Have you tried to measure the current consumption?

If the power consumption of the Thread examples are quantified? I'm not sure what you mean by this. The thread router role is not very battery friendly as it is scanning most of the time. If you want to run of a battery you should look into the sleepy end device. Maybe you can use that?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Tue, 05 Sep 2017 12:17:37 GMT

Yes, I am using the same battery for every test. If the board is connected to USB, it works uninterrupted without any power down. Is the power consumption of Thread examples quantified? We are interested in using Thread for further development, but a big constraint for us is that battery consumption should be minimal. Our use-case is a door sensor which sends door open/close information when this status changes to a cloud application. The Thread Cloud CoAP client seems to be a straightforward solution, but maybe we have to rethink using Thread if it consumes too much power. Could you recommend a non-Thread example which can achieve the similar Client-Cloud functionality as the Thread example?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Petter Myhre — Tue, 05 Sep 2017 12:11:28 GMT

And you are using the same battery for every test? And this does not happen after 10 minutes if you power it from USB? Sounds really strange, but I'll look into it. The Thread examples would be much more power hungry than for example HRM, because it will almost be scanning all the time.

RE: NRF52840 Thread example power down 10 mins after USB disconnect

meetandyhere — Tue, 05 Sep 2017 12:02:08 GMT

The board is powered by a CR2032 battery that came when we purchased the kit. It doesn't seem a battery issue because the board is powered on and works well for about 10 mins after USB disconnect. After a subsequent USB connect and disconnect, we get the same behavior. So there seems to be some pattern with the 10 min power down behavior. Also, non-Thread BLE examples, e.g. HRM from the SDK v. 13.1 run for much longer than 10 mins on battery. So I was wondering if it is some Thread-specific issue?

RE: NRF52840 Thread example power down 10 mins after USB disconnect

Petter Myhre — Tue, 05 Sep 2017 11:25:58 GMT

How is the board powered when you unplug it from the USB? Could it be a battery issue?