Sonar Phone Placement

One this I am unclear of is how the phone should be placed for sonar. I understand it should be less than 1 meter from your body but what about orientation? The photo in the documentation shows the phone parallel to your body, but other videos I have seen show the microphone being aimed towards the body. Does it matter?

Also does height matter? Should the phone be level with your body or above it? Will being slightly lower than your body cause the mattress to get in the way of the sonar?

Currently I have it placed with the microphone facing me and the phone sitting on a box making it level with my body as my nightstand does not come above my mattress. The data I am getting from sonar is not matching up with the data S Health is pulling from my watch so I am wondering if I have the phone placement wrong.

I have the Galaxy S7.

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I’m wondering the same.

Would be dependent by the mic location. General guidelines of use would be nice, because I’m willing to set up a special plateau next to my bed for this. I feel a well-aimed sonar would outscore precision movement sensor on a two persons bed.

I played around with it some last night. It appears that the microphone needs to be facing me for it to work correctly. It would not detect my movement placed parallel like this picture shows.
doc_phone_placement_sonar

I am still unsure about the correct height.

I messed around with the frequency settings and I think 18 works better than 19, 20, or 18-20. For my S7 at least.

We are unable to give a general guide on how to position the phone with sonar, as there are thousands of phones and we haven’t tested on nearly a percent of them :slight_smile:
Joking aside - many thanks for testing this out!
In an ideal setting, the mic and speaker have to be clear (not covered by anything), and that also includes the phone chassis itself. Having a clear path from the speaker to you and back to the mic will provide the clearest and strongest signal.

So a pseudogeneral guide would be to place the front of the mic or speaker to you. The mic and speaker are usually on different sides of the phone so we can never reach the ideal setting.

Yeah that makes sense. I think my mic and speaker are both on the bottom of my phone which is why facing it towards me works best. It would be awesome if a specially designed mic/speaker could be used to provide precise sonar feedback!

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Could you somehow use ear buds or headphones instead of specially desiigned speakers. Attach to the bedhead and pointing down at your chest. Will try some experiments.

Bill

Hello, I’m afraid you can’t easily… To allow sonar to work properly you need very good isolation between the mic and the speaker otherwise the signal going directly from speaker to mic will dwarf any meaningful reflected signal… such isolation is a feature of the speaker and mic in your phone as you need to not hear your own voice during phone calls (putting it simply)… so you would need to have some buds with the same features - we did not find such during our own experiments…

Thanks for reply Petr,

To isolate the speaker from the mic could you use another device to generate the noise ie lots of people own both a tablet and a phone.

Use the phone to record results and use the tablet to generate the noise ?

Bill

Hello Bill, that would not work IMHO… with isolate I mean the Misc needs to be shielded from the speaker so that the signal produced by the speaker does not directly hit the mic but rather hits an obstacle first and gets back to the mic after it is reflected…