Thingy 52, best way transmit real time data to AWS GreenGrass

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

ketil — Tue, 10 Apr 2018 10:37:33 GMT

Hi Ankit,

You write a new Eddystone URL using the Eddystone URL Characteristic in the Thingy:52 Configuration Service.

Other Eddystone beacon protocols such as UID, EID and TLM are not supported. If you need these you will have to merge our Eddystone example with the Thingy firmware.

Ketil

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Tue, 10 Apr 2018 09:08:04 GMT

Thanks Ketil, that explains it.

Also, where can I find the documentation to configure Thingy as an eddystone compatible beacon?

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

ketil — Mon, 09 Apr 2018 09:06:47 GMT

Hi Ankit,

According to the MPU9250 datasheet there might be inaccuracies of ~1%. In addition the circuitry of Thingy:52 might add to this and specifically the speaker which contains a coil and a permanent magnet.

If the fluctuations are periodic they might be caused by the Magnetometer compensation interval which periodically calibrates the magnetometer. It might also be worth looking at the Temperature compensation interval. The characteristics for changing these values are documented in the Thingy:52 GATT Profile Motion Service. Try changing these intervals and observe if they have any effect on the fluctuations.

If this does not work you might try using the raw accelerometer data which is available in the Raw data characteristic. This will give you unfiltered data unlike the Gravity Vector which is the result of sensor fusion of accelerometer, gyro and magnetometer. This means that any disturbances caused by the speaker are irrelevant.

If you use the Raw data characteristic for displaying accelerometer data note that the data is unfiltered and likely to fluctuate quite a bit. It is common to run accelerometer data through a running average algorithm. Try different sample sizes for your algorithm until you find a result you are pleased with. It will now be trivial to compare the result of using only accelerometer to the Gravity Vector. I hope you will share the result with us.

Note that the Accelerometer Full-scale range (FSR) is set to the default value of ±2g. If you want to change this you will have to modify the Thingy:52 firmware.

Ketil

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Mon, 09 Apr 2018 07:41:13 GMT

its straightforward, refer to the post by Ketil above. https://github.com/NordicPlayground/Nordic-Thingy52-Nodejs

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Mon, 09 Apr 2018 07:21:58 GMT

Thanks for the reply Ketil.

Yes, if X Axis is being exerted with 1G, then Y and Z fluctuate a bit even when stationary.

Best,

Ankit

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

priya123 — Mon, 09 Apr 2018 07:21:06 GMT

DID U SUCCED IN CONNECTING TO PI ? HOW DID U ACHIVE THIS?

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

ketil — Mon, 09 Apr 2018 07:14:34 GMT

Hi Ankit,

I'm very happy to learn that you have made such great progress. I hope you will consider open-sourcing the project on GitHub or similar as I know there is a lot of interest in this subject. Please let me know if you do.

Not immediately sure what is causing the fluctuations from the accelerometer. I will ask one of our developers who has worked with the MPU9250 IMU which is inside Thingy:52. The fluctuations might be within spec or it might be possible to do some calibration or configuration. I have a hunch that you might be right about the sensitivity but we will see.

Could you try to point the X direction downwards? Can you observe 9.81 on the X axis? Do the Y and Z fluctuate when you do this?

Ketil

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Tue, 03 Apr 2018 19:40:58 GMT

yup, done

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Tue, 03 Apr 2018 19:40:29 GMT

Hello Ketil, we finally managed to get the stack working.

Question - We have mapped Thingy's sensor values as-is to a dashboard. Everything is working ok, but when the thingy is stationary - we observed the gravity vector to jump some points.

Eg. Earth's gravity is 9.81m/s represented by z axis - perfect.

On the x and y axis, the -.10 and 0.05 sometimes change, +-.2 Is that possible?

My inference is:

There may be noise due to micro-fluctuations in power supply
My device is not calibrated correctly
Since its a deduced value, this is normal
The sensitivity is very high so it may be recording veryyy minor vibrations

Please help me zero in on the root cause

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

arunbm123 — Tue, 03 Apr 2018 09:30:01 GMT

are you developing bl-wifi gateway using Raspberry Pi ?

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

ketil — Mon, 19 Mar 2018 07:46:59 GMT

Hi Ankit and Paritosh,

Good luck with your Raspberry Pi Gateway.

Ketil

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Sat, 17 Mar 2018 07:06:53 GMT

Thanks Ketil, I and my team member Paritosh are trying to set it up. Let us get back to you with questions.

We are looking for a more permanent gateway, using Pi. Thanks!

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

ketil — Tue, 13 Mar 2018 11:35:51 GMT

Hi Ankit,

Sorry for the late reply.

The cloud options and cloud token are used to connect Thingy:52 with IFTTT. Please see the documentation on Infocenter for details. We also have a video demo of the IFTTT cloud functionality.

We have reference apps for Android, iOS and Web showing how to use your phone as a gateway for Thingy:52. The source code is available on GitHub. If you would like a more permanent gateway we also have examples for Raspberry Pi.

Ketil

RE: Thingy 52, best way transmit real time data to AWS GreenGrass

Ankit Madan — Wed, 07 Mar 2018 15:40:38 GMT

Hi, any suggestions please?