NimBLE_Client + Beacon BLE

[lucasromeiro]

Hello, first I would like to congratulate you for the excellent work!

I have a small challenge:

I always used esp8266.
Now I need to connect an esp32 to a temperature and humidity (BLE) sensor.

I'm going to send a picture of him here.

I used your Scan example and it worked, found the equipment!

But, I am not able to connect to the BLE beacon to receive the temperature and humidity.
I tried to use the example NimBLE_Client.ino but was unsuccessful.

Would you help me? I didn't find many instructions and I really liked the example because it is very organized, I would like to make it work.

As there are no instructions in the example, I did not change anything.

I don't know what to do to change and read the Beacon variables (temperature and humidity)

Thank you so much for helping us all!

https://sc04.alicdn.com/kf/H4188ed456d95460a96dcffc01e015e6fl.jpg

Advertised Device found: Name: ThermoBeacon, Address: 70:f7:00:00:11:1a, manufacturer data: 100000001a110000f770830cef01be04c4300000, serviceUUID: 0xfff0, txPower: 0

[h2zero]

Hi @lucasromeiro I am unable to see the picture in the link.

I can say that if you have saved the pointer to the advertised device or the address of it you should be able to connect to it. Maybe you could provide a log output and/or code example?

[lucasromeiro]

Hello, I used the CLIENT example. I didn't change anything. How can I change this information?

Advertised Device found: Name: ThermoBeacon, Address: 70:f7:00:00:11:1a, manufacturer data: 100000001a110000f770830cef01be04c4300000, serviceUUID: 0xfff0, txPower: 0

[h2zero]

Ok, the easiest thing to change is this line to the service UUID of your device (FFF0).

So change that to if(advertisedDevice->isAdvertisingService(NimBLEUUID("FFF0")))

That should get you connected to it, after that you will need to get the services and characteristics from it and read/write to them. I don't know what the UUID's are except for the one you mentioned but you can use NimBLEClient::discoverAttributes() after connecting to get the database from the device. After that you could loop through each service/characteristic and print the UUID's.

We can go over that process once you get connected to the device, let me know.

[lucasromeiro]

NICE!!!
The result of FFF0:

THANKS!!!!

Can you explain better how to do the loop to discover the services and features?

After I discover these services, how do I use them?

One last important question, I have another BLE device, but it does not return this code 000F that worked on this one, how do I do it in these cases? Would I put the name? the MAC? Do you have these options?

Thank you very much for all your help, it will solve a problem of mine !!!

Other beacon scan:

Found another manufacturers beacon!
strManufacturerData: 29 [6][0][1][9][20][2][EA][31][EB][8A][7A][7A][7F][22][6E][EB][C2][7E][D5][57][C8][43][24][54][D6][D3][18][2F][11]
Device name: T201

[h2zero]

You will have quite a bit of work to do here but I will try to explain the work flow as best I can.

• After connection you can call NimBLEClient::discoverAttributes(); which will get the attribute database from the device.
• Next you want to do something with those attributes, probably read their UUID's/values. To do that you could use something like this:

 auto pServices = pClient->getServices();
 for (auto pService : *pServices)  {
      Serial.printf("Found service: %s\n", pService->getUUID()->toString.c_str());
      auto pCharacteristics = pService->getCharacteristics();
      for (auto pCharacteristic : *pCharacteristics) {
          Serial.printf("Found characteristic: %s  ", pCharacteristic->getUUID()->toString.c_str());
          Serial.printf("Value: %s\n", pCharacteristic->readValue().c_str())
      }
  }

To connect to the other device I suggest comparing the name instead of the UUID since it does not advertise it.

[lucasromeiro]

Hello, I managed to adapt to make it work!
Look how it looks:

The code I modified some things that had silly errors and put in this place. is correct?

I did not find the codes for temperature and humidity. =(

https://btprodspecificationrefs.blob.core.windows.net/assigned-values/16-bit%20UUID%20Numbers%20Document.pdf

Here is a table of all the codes, none of them are for temperature and humidity.
What do you suggest I do?

as for your suggestion to put the name of the sensor, I think it will be better to put MAC, so I will be able to differentiate both, Would it be possible to work like this?

if(advertisedDevice->isAdvertisingService(NimBLEUUID("MAC HERE!!!!")))

[lucasromeiro]

I was able to find it at MAC!

But I still don't know how to put a command to read temperature and humidity. ☹

[h2zero]

Glad you got that sorted.

You will need to change the service/characteristic get() calls to use the UUID's the device has for those values. Looks like it's the service UUID ffe0 and characteristic UUID's fff5 and fff3. When you read the values from those you will want to convert the string to an integer value like this : int temperature = pChar->readValue<int>() and uint16_t humidity = pChar->readValue<uint16_t>()

[lucasromeiro]

Hello, I tried the combinations that passed me and I didn't get any results.
Look how it looks:

Did I do something wrong?

[h2zero]

Sorry, I didn't look well enough at the service UUID's. The service you want is 180a and the characteristics appear to be 2a2a and 2a50. You will have to play around with them all to find the data you're looking for or use a phone and nRFConnect app to be more precise.

[lucasromeiro]

Hi!

I did the tests, look at the prints below.

I get paid but I still can't see the temperature and humidity.
I read somewhere that the 2 bytes received that have either changed LITTLE ENDIAN) Something like that.
I'm a novice, I may be confusing.

What can I do?

For 180a (2a2a):

For 180a (2a50):

what is this(tasty)?

[h2zero]

what is this(tasty)?

lol that's just silly code that is for demonstration, you should remove all of that as you don't need it.

I don't know what the values are that you are getting, the device doesn't seem to be using the standard temp/humidity characteristics. Maybe search google for information on that device, probably someone has figured it out already.

One thing you can try also is changing the temperature read to this: int16_t temperature = pChar->readValue<int16_t>()

[lucasromeiro]

Got it, how do you suggest that I search?
As I am not a profound connoisseur of the area, I am not sure how to look.
What words / phrases do I search for?

Wouldn't this data that I received and show above be correct and out of order? Perhaps it is correct and just needs to be interpreted correctly. What do you think?

TEST: int16_t temperature = pChar->readValue<int16_t>():

For 180a (2a50):

For 180a (2a2a):

These codes according to the table say something else. Are we not looking at the wrong data?

2a2a:

2a50:

FONT: https://btprodspecificationrefs.blob.core.windows.net/assigned-values/16-bit%20UUID%20Numbers%20Document.pdf

[h2zero]

Yes those do look to be the wrong data, however I do not see the standard temp / humidity characteristics available so I guessed that they used those instead for some reason. The temperature should be UUID 2a6e and humidity 2a6f but I do not see them in the list. Perhaps it only advertises those values?

[lucasromeiro]

Thanks for the tip, I looked at the nRFConnect app.

Look at the result:

it helps?
Was that what you wanted?