Skip to content

dblanding/bluetooth

BranchesTags

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

3 Commits
imgs
imgs
 
 
mcaleer
mcaleer
 
 
upy-lib-example
upy-lib-example
 
 
.gitignore
.gitignore
 
 
README.md
README.md
 
 

Repository files navigation

Notes on learning to implement Bluetooth communication

  • Early project used HC-05, 06 BT modules to enable communication between 2 Arduinos (Tele-op Omni-Car)

  • My goal now is to implement BT to enable PS-4 gamepad to talk to Picobot

Get some experience by following Pico BT example, under Pico MicroPython Examples.

  • Followed the Instructions at Chapter 6: Working with Bluetooth in MicroPython
    • Installed ble_advertising.py and ble_temp_sensor.py on Pico #5.
    • Started ble_temp_sensor.py.
    • Producing this output in thonny:
    Sensor name Pico 28:CD:C1:0B:30:D2 write temp 28.45 degc write temp 28.45 degc write temp 27.51 degc write temp 27.98 degc write temp 27.98 degc write temp 27.98 degc
    • This BT device didn't show up at all in my phone.
    • It did show up on my laptop but failed to pair, after which it would no longer show up.
    • I could stop ble_temp_sensor.py and restart it and it would again show up on my laptop.
    • This is as far as I got...

Got a pair of Pico W devices sending & receiving via Bluetooth

This project implements Kevin McAleer's tutorial on Bluetooth Remote Controlled Robot which shows the use of aioble module to allow BT to work asynchronously.

  • Kevin's tutorial shows using Bluetooth to connect a remote control (Pimoroni LCD screen wuth buttons) to his Burgerbot
  • The server on Kevin's project imports pimoroni.py module which I chased down at the Pimoroni website
  • The client code needs burgerbot.py module which I found at Kevin McAleer's Burgerbot repo
    • burgerbot.py needs motor and servo, which I wasn't able to find.
      • No matter... I'm not using burgerbot anyway.
  • My project (below) uses a different LCD but aims to copy the Pico-to-Pico BLE communication exactly the same

LCD & Remote Pico

My Remote (bluetooth server)

  • Instead of using the Pimoroni display, I am using the Pico LCD 1.14
  • Revised remote.py to my_remote.py to use the Pico LCD 1.14 device instead of the Pimoroni one.

My Robot (bluetooth client)

  • Revised robot.py to not import burgerbot

Results

  • Works great! Here is the output of the remote process:
>>> %Run -c $EDITOR_CONTENT registering services peripheral task started blink task started not connected not connected not connected not connected Connection from Device(ADDR_PUBLIC, 28:cd:c1:0a:4a:e2, CONNECTED) connected: True A A B B CTRL CTRL UP UP DOWN DOWN LEFT LEFT RIGHT RIGHT
  • But it crashes (after about a minute):
Traceback (most recent call last): File "<stdin>", line 239, in <module> File "uasyncio/core.py", line 1, in run File "uasyncio/core.py", line 1, in run_until_complete File "uasyncio/core.py", line 1, in run_until_complete File "<stdin>", line 237, in main File "uasyncio/funcs.py", line 1, in gather File "uasyncio/core.py", line 1, in run_until_complete File "<stdin>", line 215, in peripheral_task File "aioble/device.py", line 295, in __aexit__ File "aioble/device.py", line 216, in disconnect File "aioble/device.py", line 232, in disconnected File "aioble/device.py", line 232, in disconnected File "uasyncio/core.py", line 1, in run_until_complete File "aioble/device.py", line 198, in device_task File "uasyncio/event.py", line 1, in wait CancelledError: >>>
  • Meanwhile, this is the output of the robot process (on a subsequent run):
>>> %Run -c $EDITOR_CONTENT blink task started blink task stopped starting peripheral task Robot Remote not found blink task started blink task stopped starting peripheral task Found KevsRobots UUID(0x1848) Found Robot Remote Service Connecting to Device(ADDR_PUBLIC, 28:cd:c1:0a:4c:25) Connected A button pressed A button pressed B button pressed B button pressed CNTR button pressed CNTR button pressed UP button pressed UP button pressed DOWN button pressed DOWN button pressed LEFT button pressed LEFT button pressed RIGHT button pressed RIGHT button pressed
  • Until the crash:
something went wrong; disconnected blink task started blink task stopped starting peripheral task Found KevsRobots UUID(0x1848) Found Robot Remote Service Connecting to Device(ADDR_PUBLIC, 28:cd:c1:0a:4c:25) Connected

Efforts to resolve crashing issue

  • Posted a comment on Kevin's Youtube channel
  • I noticed that another person posted a comment (~ 1 month ago) reporting a GattError after ~ 1 minute.
  • I uploaded the Pimoroni micropython version 1.20.4 (to replace the Paspberry Pi version) but this didn't solve the problem.
    • However it answered my question about where to find the missing modules (pimoroni, motor, servo). They are included in this version of micropython.
MicroPython 856e08b1931b88271816a2f60648f6ff332235b2, picow v1.20.4 on 2023-08-04; Raspberry Pi Pico W with RP2040 Type "help()" for more information. >>> help("modules") __main__ breakout_dotmatrix gc pimoroni_bus _boot breakout_encoder gfx_pack pimoroni_i2c _boot_fat breakout_encoder_wheel hashlib plasma _onewire breakout_icp10125 heapq pngdec _rp2 breakout_ioexpander hub75 qrcode _thread breakout_ltr559 interstate75 random _uasyncio breakout_matrix11x7 inventor re _webrepl breakout_mics6814 io rp2 adcfft breakout_msa301 jpegdec select aioble/__init__ breakout_paa5100 json servo aioble/central breakout_pmw3901 lwip socket aioble/client breakout_potentiometer machine ssl aioble/core breakout_rgbmatrix5x5 math struct aioble/device breakout_rtc micropython sys aioble/l2cap breakout_scd41 mip/__init__ time aioble/peripheral breakout_sgp30 motor uasyncio/__init__ aioble/security breakout_trackball neopixel uasyncio/core aioble/server breakout_vl53l5cx network uasyncio/event array builtins ntptime uasyncio/funcs automation cmath onewire uasyncio/lock binascii collections os uasyncio/stream bluetooth cppmem pcf85063a uctypes boot cryptolib picoexplorer urequests breakout_as7262 dht picographics version breakout_bh1745 ds18x20 picokeypad webrepl breakout_bme280 encoder picoscroll webrepl_setup breakout_bme68x errno picounicorn websocket breakout_bmp280 framebuf pimoroni zlib Plus any modules on the filesystem >>>

Time passes... Haven't figured out what is causing the code to crash

Decided to try approaching this from a new direction. Try to find another aioble server/client example that doesn't crash.

MicroPython aioble library GitHub repo has a temperature sensor / client example which I will now try out.

  • That works fine too, for about a minute. Then I get this error:
Connecting to Device(ADDR_PUBLIC, 28:cd:c1:0a:4c:25) Temperature: 24.53 Temperature: 24.79 Temperature: 24.77 Temperature: 24.53 Temperature: 24.93 Temperature: 25.37 Temperature: 24.92 Temperature: 24.98 Temperature: 25.12 Temperature: 25.16 Temperature: 25.16 Temperature: 24.80 Temperature: 24.52 Temperature: 24.22 Temperature: 24.36 Temperature: 24.32 Temperature: 24.08 Temperature: 23.89 Temperature: 24.46 Temperature: 24.94 Temperature: 25.23 Temperature: 25.12 Temperature: 24.65 Temperature: 24.77 Temperature: 24.61 Temperature: 24.90 Temperature: 24.55 Temperature: 24.45 Temperature: 24.69 Temperature: 24.79 Temperature: 24.80 Temperature: 24.73 Temperature: 24.49 Temperature: 24.70 Temperature: 24.07 Temperature: 24.24 Temperature: 23.96 Temperature: 24.14 Temperature: 24.54 Temperature: 24.13 Temperature: 24.12 Temperature: 24.46 Temperature: 24.19 Temperature: 24.36 Temperature: 24.28 Temperature: 24.40 Temperature: 24.44 Temperature: 24.57 Temperature: 24.89 Temperature: 24.93 Temperature: 25.04 Temperature: 24.56 Temperature: 24.32 Traceback (most recent call last): File "<stdin>", line 63, in <module> File "uasyncio/core.py", line 1, in run File "uasyncio/core.py", line 1, in run_until_complete File "uasyncio/core.py", line 1, in run_until_complete File "<stdin>", line 58, in main File "aioble/client.py", line 258, in read GattError: 31
  • Without disturbing the sensor (server), I restarted the client, which then continued without errors, but the value of the temperature was no longer changing.
Connecting to Device(ADDR_PUBLIC, 28:cd:c1:0a:4c:25) Temperature: 24.16 Temperature: 24.16 Temperature: 24.16 ...
  • From this it looks like the ble client was continuing to get temperature data but the server was no longer sending fresh data.
  • Moved the server to run under Thonny.
    • First start the server.
    • Then started the client.
    • Exactly 1 minute after the client connects, the server crashes with this traceback:
Connection from Device(ADDR_PUBLIC, 28:cd:c1:0a:4a:e2, CONNECTED) Traceback (most recent call last): File "<stdin>", line 68, in <module> File "uasyncio/core.py", line 1, in run File "uasyncio/core.py", line 1, in run_until_complete File "uasyncio/core.py", line 1, in run_until_complete File "<stdin>", line 65, in main File "uasyncio/funcs.py", line 1, in gather File "uasyncio/core.py", line 1, in run_until_complete File "<stdin>", line 58, in peripheral_task File "aioble/device.py", line 295, in __aexit__ File "aioble/device.py", line 216, in disconnect File "aioble/device.py", line 232, in disconnected File "aioble/device.py", line 232, in disconnected File "uasyncio/core.py", line 1, in run_until_complete File "aioble/device.py", line 198, in device_task File "uasyncio/event.py", line 1, in wait CancelledError:

I think I may have found the cause of the problem.

  • Edited server code: last line in coroutine async def peripheral task():

    • originally was: await connection.disconnected()
    • after editing: await connection.disconnected(timeout_ms=None)

  • Apparently, the default value is 60_000 (60 sec).

  • Indeed the code for device.py in the aioble library module has a DeviceConnection class which has a coroutine async def disconnected(self, timeout_ms=60000, disconnect=False)

  • Next I want to see if this will fix the problem with Kevin McAleer's code.

    • Yep, that seems to fix the problem. Now the code runs indefinitely.

About

Learning to implement BLE on Pico devices

Topics

async micropython bluetooth-low-energy vhotsmcomp pico-w

Resources

Readme
Activity

Stars

4 stars

Watchers

2 watching

Forks

0 forks
Report repository

Releases

No releases published

Packages

 
 
 

Contributors

Languages