Add BLE Communication #96
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Signed-off-by: Kozova1 <mug66kk@gmail.com>
Signed-off-by: Kozova1 <mug66kk@gmail.com>
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Currently has a limitation: Notify doesn't work with the current protocol, since it seems to be limited to about 20 bytes of payload. Maybe a more compact protocol can be used for BLE (maybe sending it as packed binary data?), or even just have a notify characteristic that tells the driver to read the "real" characteristic. |
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It might be doable if we send the flexion values as shorts (16bit), and since they're 0-4095 always we can also use the upper 4 bits of the short for various booleans. This way we have exactly enough space, with maybe a few single bits left over. I'd prefer not to do this because this makes the implementation way harder on the decoder, and doesn't leave any room to expand in the future. What I think should be done instead is to add a "data updated" characteristic, that simply notifies when the glove's data was changed, and then opengloves will need to know that when it receives that, it should read the full glove data. |
| @@ -25,6 +27,9 @@ void setup() { | |||
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| void loop() { | |||
| if (comm->isOpen()){ | |||
| #if COMMUNICATION == COMM_BLE | |||
| BLE.poll(); | |||
| #endif | |||
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This is here because BLE needs polling, otherwise connections will fail.
I don't really like the way I did it here, but I'm not sure whether I should add a poll-like method to ICommunication or just keep it this way.
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where is BLE defined?
and yeah, probably best to add a new method to ICommunication, but let's see what Lucas says.
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It's a global provided by the ArduinoBLE library.
| if (input == NULL) { | ||
| return false; | ||
| } | ||
| strcpy(input, reinterpret_cast<const char*>(m_rx.value())); |
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Is this an std::string? ideally use .c_str() if so, or if it's an arduino string iirc there's a .toCharArray - might that be helpful?
| #define BLE_SERVICE_UUID "090b69e6-d509-4c32-8b20-5f8b947b253a" | ||
| #define BLE_TX_UUID "0eac19b9-5441-40bc-afca-cffb4380714d" | ||
| #define BLE_RX_UUID "54cd1674-a8aa-4b15-ac74-361b0084877f" |
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I'm not too familiar with the BLE spec so feel free to correct me - do these identifiers have to be unique between devices? (so no two gloves can have the same uuid?)
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I don't think so - I believe these just describe the "service" - in this case, the "serial" interface.
| int initialFlexion[5] = { 0 }; | ||
| char* encoded = encode(initialFlexion, 0, 0, false, false, false, false, false, false, false, false); | ||
| m_tx.writeValue(encoded, strlen(encoded)); |
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It might not be, but it's better to initialize these to have well defined values instead of possibly causing undefined behavior
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In any case, the array should probably 10 long, otherwise if splay is enabled this will cause reading beyond the end of the array. Will fix soon.
Signed-off-by: Kozova1 <mug66kk@gmail.com>
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Unfortunately, due to private reasons I won't be able to work on the opengloves side |
| #define COMM_BTSERIAL 1 | ||
| #define COMM_BLE 2 | ||
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| #define BLE_SERVICE_UUID "090b69e6-d509-4c32-8b20-5f8b947b253a" |
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I recommend using standard chars for uart: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v13.0.0%2Fble_sdk_app_nus_eval.html
It is widely supported, you can download NRF connect for your phone, I use it quite a lot in my project
This PR adds BLE communication to the LucidGloves firmware.
Opengloves doesn't support it yet, so the only way to test it ATM is to use some kind of BLE explorer app on your phone.
I verified that this works and sends the data as expected on my phone.