Improve consumption by UUID organisation

RE: Improve consumption by UUID organisation

Olfox — Tue, 21 Jun 2022 07:58:57 GMT

Hi Sigurd,

Thanks a lot for your help and advices. Now it is clear with UUID :) .

You are right, now i will fine tune with these parametre and check if it doesn't bring to much latency to the user exeprience.

i'm using module ( insight sip isp1907ht),

And DCDC is enable in main.c init

I had to change my thermal camera recently, i'm facing a new " issue" that i quikly solved but not sur it is the good way to proceed.

But i created a new ticket for that :)

in case you are interrested to have a look ;)

Communicate with sensor in timer interrupt occurs issue

Thanks a lot again for your help, it is precious !

RE: Improve consumption by UUID organisation

Sigurd — Mon, 20 Jun 2022 11:52:37 GMT

The main benefit with notifications is that it's GATT server initiated, so you can send it whenever the value changes. But if you don't need all the values, then the read request is a good choice as well. I was not suggesting use both.

I think there are better ways improve power consumption in this case, e.g. take a look at the BLE connection interval you are using, if you have DCDC components on your board, enable DCDC mode, add external LF crystal to your board if you don’t have that.

You might find this blog post useful: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/optimizing-power-on-nrf52-designs

RE: Improve consumption by UUID organisation

Olfox — Fri, 17 Jun 2022 10:09:28 GMT

Hi Sigurd,

OK that's clear now that UUID is not send every time, but i guess just at each service discovery when it connect. so the less service and charac i have the less data will be send.

[quote userid="15146" url="~/f/nordic-q-a/88988/improve-consumption-by-uuid-organisation/372958#372958"]The value is the same 9 out 10 times? The central read this value 10 times per second? Why not just send a notification with the value when it changes?[/quote]

The 16byte data of ircam will change each 100ms for sure.

The pressure sensor is read each second.

So we decide that mobil app read 10times per second the carac ircam, and one time per second the pressure charac.

Idea was to use only one carac with both data but i realise that it is a waste of radio on time if uuid is not send each time and only 3byte with attribute opcode and attribute handle are send during read request.

Is notification (even at 10hz) more energy efficient ? Because i guess it send notification, then receive a read request, and finally read response with data s i 'loose' 10 notifications per second instead of just let the mobile app read by it self at its interval.

RE: Improve consumption by UUID organisation

Sigurd — Fri, 17 Jun 2022 08:43:55 GMT

Hi,

[quote user=""]1) Is all the charac and services UUID send at each connexion to allow central to list services in peripheral? [/quote]

No. If there is nothing to send, only an Empty PDU will be sent.

[quote user=""]2) Does central send UUID of the charac to be read in each read request (meaning,128bits = 10 times per second in my case?)[/quote]

No, it uses the Attribute Handle, not the complete UUID.

[quote user=""]3) Even if tpms value will be 9/10 the same, Is it more profitable to have all data in one charac or keep as it is at the meoment in a second charac?[/quote][quote user=""]- Temperature Matrix averaged: 16 bytes. Read in loop 10times per second, in connected mode[/quote]

The value is the same 9 out 10 times? The central read this value 10 times per second? Why not just send a notification with the value when it changes?