RPI Pico W GPS Bluetooth and Azure IoT Hub

A set of Arduino Sketches for execution on a RPI Pico W building up to and including sending GPS location data over Bluetooth in BT Classic mode. Also send GPS data to an Azure IoT Hub.

---

Update/Correction

The calculation of Latitude and Longitude from NMEA data has been corrected ina a number of projects as per my blog post :GPS: NMEA 101.

---

Blog Post

RPI-Pico-Arduino-AzSDK: Bluetooth and GPS Update

Hardware

Bluetooth

The RPI PicoW comes with Bluetooth. The BSP used has been updated to include that.

• The repository for the Pico W Arduino BSP: earlephilhower-arduino-pico on Github
• Installation instructions
• Bluetooth documentation for the BSP

Arduino GPS Receiver

• Arduino Compatible GPS Receiver Module Jaycar (Australia) CAT.NO: XC3710
• https://www.jaycar.com.au/arduino-compatible-gps-receiver-module/p/XC3710
• nblox NEO-7M Module BAUD is 9600

Projects

1.USART1 Echo

• Echo text from Serial terminal (uppercased) back to it after first passing it through USART1 in loopback mode.

2.Basic GPS

• Read and echo NMEA sentences to Serial terminal

3.InteractiveGPS

• Can send commands to device from Serial terminal:
  • s: Start
  • p: Stop
  • n: No filter on messages
  • n: Filter all (none displayed)
  • a: Display GPGGA - Global Positioning System Fix Data
  • l: Display GPGLL - Geographic Position, Latitude / Longitude
  • v: Display GPGSV - Satellites in view

4.LocationGPS

• Filter all messages except GPGGA
• Get latitude, longitude and height
• Note that string processing of NMEA messages is explicit rather than using existing libraries.
• Commands:
• • s: start
  • p: stop
  • n display none
  • d: Display GPGGA string
  • l: Display as location tupple
  • t: Display as json telemetry
• Has been modified for Sketch 7.
  • Parsing of NMEA in "reusable" function.

5.BTSerialUppercase

• Receive text over Bluetooth and echo it back after upper-casing it.
• Is the Android IDE SerialBT BTSerialUppercase example
• Added echo to IDE Terminal of the characters being passed, unadulterated.
• Note: Bluetooth Classic, not BLE.
• Found the Android phone app Serial Bluetooth Terminal was easier to pair than desktop.

6.BluetoothGPS

• Send Location data over Bluetooth to paired host.
• As per 4 but data and commands over Bluetooth (Merger of 4. and 5.)
• Receives commands over BT as per BTSerialUppercase and interprets them as per LocationGPS.
  • That is, sends Location data back over BT when available as per LocationGPS (to SerialBT instead of Serial)
• Note: Bluetooth Classic, not BLE.

7.Azure_IoT_Hub_GPS

• Send GPS location data, generated as per LocationGPS, as Telemetry to an Azure IoT Hub.
  • Minus interactive commands.
• Filter all messages except GPGGA Get latitude, longitude and height
• From LocationGPS uses json location option.
  • That is, all creation of the telemetry string explicitly uses string processing rather than GPS and json classes.
• Now works.

8. read-d2c-messages

• .NET Console app to monitor messages sent to IoT Hub by 7.
• Uses .NET Core 3.1
• See code for connection details.

Nb: Was found that in Azure IoT Explorer, needed to paste same connection string as the Custom Endpoint for the device. Built-in [Yes] option did not work.

9. read-d2c-messages-Net6

• As per 8. but uses .NET 6.0
• See code for connection details.

---

Footnote

Working on a Blazor app to display the GPS coordinates sent by 8. on a map. See djaus2/GPSMapIoTHub