How to turn on/off mesh

RE: How to turn on/off mesh

Trond Einar Snekvik — Thu, 07 Jan 2016 14:22:21 GMT

That seems reasonable. If you don't want to push data to the sensor, you can actually do this only by advertising, if you follow the packet format. Enabling the mesh will force you to do some scanning, and it might take up to 100ms to get a response from the master, but it's not an unreasonable approach. The end node does not need to reestablish its network role, or negotiate some slot from the master in any way. It can wake up, send, and go back to sleep, without any management overhead.

RE: How to turn on/off mesh

d21d3q — Thu, 07 Jan 2016 14:17:13 GMT

How about waking up end node (some sensor) from deep sleep, ask some Master through mesh for instructions (to transfer some data) and go back to sleep? In this case question is if end node needs to discover network on reconnection as ZigBee does?

RE: How to turn on/off mesh

Trond Einar Snekvik — Thu, 07 Jan 2016 12:54:15 GMT

Unfortunately, no. When turned off, the mesh doesn't use the radio at all, and will not be able to send or receive anything. The mode you're requesting requires a surprising amount of extra functionality, as the battery powered node cannot be in RX mode constantly (it's extremely power consuming). Therefore, the "router" node has to buffer all incoming messages while waiting for the end-node to attach in some low-power fashion, like a regular BLE connection. This is the approach I would recommend for the mesh; let router devices scan for end node's advertisements, and connect. Transfer all data since the last connection, and disconnect again. Alternatively, keep a connection running, but keep the connection interval high, as to conserve power in the end node. If you want several end-nodes at each router, you should make the router the master in the connections (requires SD120 or SD130).

RE: How to turn on/off mesh

d21d3q — Thu, 07 Jan 2016 12:39:32 GMT

Does it mean that devices with turned off mesh is working like ZigBee end node? Only listening and not participating in forwarding messages? I would like to have mesh end nodes running on battery and some routers with no power constraints .

RE: How to turn on/off mesh

sphudson — Tue, 08 Sep 2015 18:45:57 GMT

Thank you very much, Trond!

RE: How to turn on/off mesh

Trond Einar Snekvik — Tue, 08 Sep 2015 07:16:07 GMT

The framework now supports start/stop actions for the radio activity, see release v0.6.9. Note that this only stops radio activity, while the memory remains allocated and local functionality is kept.

It works by aborting the running timeslot, and stops all ordering of new ones from the Softdevice.

RE: How to turn on/off mesh

Susheel Nuguru — Fri, 04 Sep 2015 06:19:14 GMT

I am not sure, is there any events that you were expecting?

RE: How to turn on/off mesh

sphudson — Thu, 03 Sep 2015 00:50:17 GMT

Aryan, My last comment got deleted for some reason. The problem is that ts_sd_event_handler() is never called. Can you please provide some clues as to why it isn't being called? Thanks -stan

RE: How to turn on/off mesh

Susheel Nuguru — Wed, 26 Aug 2015 07:51:00 GMT

I forgot to check the error return value of sd_radio_session_close. I have edited the answer now. Did you check if it returned NRF_SUCCESS? After that it should atleast get NRF_EVT_RADIO_SESSION_CLOSED event.

RE: How to turn on/off mesh

sphudson — Tue, 25 Aug 2015 21:07:52 GMT

Aryan, I tried what you suggested above and it isn't working. In fact, the ts_sd_event_handler() function isn't even being called. Nor is the rbc_mesh_sd_irq_handler() function. I'm using the template example on a PCA10031 dongle. And, I have confirmed that the mesh is working because it is periodically sending (and receiving) updates between the dongle and another board running the mesh. Can you please confirm that your suggestion is correct? thanks

RE: How to turn on/off mesh

Susheel Nuguru — Mon, 24 Aug 2015 16:53:55 GMT

the receiver is switched off before the slot has ended, and if no new slot is requested, then it remains off. Timeslots can be used both for transmission and reception of data

RE: How to turn on/off mesh

sphudson — Mon, 24 Aug 2015 15:46:15 GMT

Thank you for the quick reply. I'll implement that solution. Does the sd_radio_session() call turn off the receiver as well? I am not completely familiar with the inner-workings of the mesh and timeslot handler, but is the receiver basically on all of the time and the timeslots are used to process not only transmissions but also reception of data from other nodes? Thanks

RE: How to turn on/off mesh

Susheel Nuguru — Mon, 24 Aug 2015 12:10:56 GMT

The turning on and off of mesh is not exposed. It should be, but we didn't really consider it at first. I think the easiest fix is to stop the timeslots. you would have to modify the way the radio events are handled to keep it from restarting the session, but it should be pretty straight forward.

in ts_sd_event_handler instead of renewing the timeslot, renew it based on some condition something like this for example

        case NRF_EVT_RADIO_SESSION_IDLE:
            if(!switch_it_off)
                  timeslot_order_earliest(TIMESLOT_SLOT_LENGTH, true);
            else
                  err_code = sd_radio_session_close();
                  if (err_code != NRF_SUCCESS) {handle_error}
            break;

so when the timeslot-start signal isn't triggered, there should be no unexpected hardware usage.