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README.md

Bluetooth - People Counting (AK9753)

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Overview

This project aims to implement a people counting application using SparkFun Human Presence Sensor Breakout - AK9753 (Qwiic) and Sparkfun development board Sparkfun Thing Plus MGM240P with integrated BLE stack.

Table Of Contents

SDK version

Software Required

Hardware Required

Connections Required

The hardware connection is shown in the image below: hardware connection

Listed below are the port and pin mappings for working with this example.

  • Board: BRD2704A - SparkFun Thing Plus Matter - MGM240P

    GPIO Pin Connection Pin function
    GPIOB PB00 Button
    SCL PB03 I2C Clock
    SDA PB04 I2C Data

Note

  • Some boards do not have an integrated button. In this case, the user has to connect an external button to the board and config this button in accordance with project specifics.

    btn_config

  • To make the driver more stable, use a ceramic capacitor (ex: Ceramic Capacitor 104) to avoid the anti-vibration button used in the project as below:

    btn_setup

Setup

To test this application, you can either create a project based on an example project or start with a "Bluetooth - SoC Empty" project based on your hardware.

Note

Create a project based on an example project

  1. From the Launcher Home, add your hardware to My Products, click on it, and click on the EXAMPLE PROJECTS & DEMOS tab. Find the example project filtering by "people".

  2. Click Create button on the Bluetooth - People Counting (AK9753) example. Example project creation dialog pops up -> click Create and Finish and Project should be generated. create_project

  3. Build and flash this example to the board.

Start with a "Bluetooth - SoC Empty" project

  1. Create a Bluetooth - SoC Empty project for your hardware using Simplicity Studio 5.

  2. Copy all attached files in inc and src folders into the project root folder (overwriting existing app.c).

  3. Import the GATT configuration:

    • Open the .slcp file in the project.

    • Select the CONFIGURATION TOOLS tab and open the Bluetooth GATT Configurator.

    • Find the Import button and import the attached gatt_configuration.btconf file.

    • Save the GATT configuration (ctrl-s).

  4. Open the .slcp file. Select the SOFTWARE COMPONENTS tab and install the software components:

    • [Platform] → [Driver] → [I2CSPM] → default instance name: qwiic
    • [Platform] → [IO Stream] → [IO Stream: USART] → default instance name: vcom
    • [Platform] → [Driver] → [Button] → [Simple Button] → instance name: btn0. If using the BRD2704A board, configure btn0 to select the "Selected Module" as PB00
    • [Application] → [Utility] → [Log]
    • [Third Party Hardware Drivers] → [Display & LED] → [SSD1306 - Micro OLED Breakout (Sparkfun) - I2C] → use default configuaration
    • [Third Party Hardware Drivers] → [Service] → [GLIB - OLED Graphics Library]
    • [Third Party Hardware Drivers] → [Sensors] → [AK9753 - Human Presence Sensor (Sparkfun) - I2C]

  5. Build and flash the project to your device.

Note

A bootloader needs to be flashed to your board if the project starts from the "Bluetooth - SoC Empty" project, see Bootloader for more information.

How it Works

Application overview

Application overview

GATT Configuration

The application is based on the Bluetooth - SoC Empty example. Since the example already has the Bluetooth GATT server, advertising, and connection mechanisms, only minor changes are required.

A new custom service (People Counting) with 8 characteristic must be added.

  • People Entered So Far:

    • [Readable] - Get total number of people enter the room

    • [Writable] - Clear total number of people enter the room

  • People Count:

    • [Readable] - Get number of people in the room

    • [Writable] - Clear number of people in the room

  • Room Capacity:

    • [Readable] - Get the capacity of the room

    • [Writable] - Set the capacity of the

    • [Notifiable] - Get notification of room status( full or empty)

  • Lower Threshold:

    • [Readable] - Get the lower threshold

    • [Writable] - Set the lower threshold

  • Upper Threshold:

    • [Readable] - Get the upper threshold

    • [Writable] - Set the upper

  • IR Threshold:

    • [Readable] - Get the IR threshold

    • [Writable] - Set the IR threshold

  • Hysteresis:

    • [Readable] - Get hysteresis

    • [Writable] - Set hysteresis

  • Notification status:

    • [Readable] - Get the notification status

    • [Writable] - Set the notification status

People Counting Implementation

Application initialization

Application init

Sensor initialization

Application Workflows

  1. Initialize the peripherals, the Bluetooth stack

  2. Initialize and load the NVM3 configurations

  3. Initialize the AK9753 sensor with the configuration loaded from NVM3:

    • Upper threshold: 100
    • Lower threshold: -200
    • IR Threshold: 800
    • Hysteresis: 50

  4. Initialize OLED display

  5. Start a periodic timer with a period of 1000ms, The timer callback will fire an external event to the BLE stack and the event handler will display people counting data from the result of the counting algorithm calculation.

  6. After the sl_bt_evt_system_boot_id event arrives, application sets up the security manager to bond with an iOS/Android device. And then start advertising.

  7. Handle GATT event to help users configure the counting algorithm and get the result from the algorithm calculation over the EFR32 connect mobile

Counting algorithm

The AK9753 sensor includes 4 IR sensors that are arranged in the picture below, and the detection algorithm will be based on the values of the IR2 and IR4.

sensor

We divide the ambient space into 3 areas: front, back and middle zone. Whenever a person appears in one of these 3 zones, a trigger will happen to notify that there is a person in this area and the status of this area will be also stored in a list. The order of these state values in the list is used to detect the moving direction of the person. For example, if the consecutive states in the list are 0, 1, 3, 2 or 0, 2, 3, 1 this means a person has been detected in one direction or the other.

entering pattern

leaving pattern

When no-one is seen in either of the two zones, the list of states will be reset. The workflow of the whole algorithm is described in the picture below.

algorithm_workflow

OLED Display

  • Display the current people count and people entered so far values.

Button

  • Press the button to reset the people count to 0.

Room status notification

  • To receive the status of the room (full or empty), the user should use the Simplicity Connect Mobile Application to enable notification
  • If the number of people counts is greater than the room capacity then the device will send a "room is full" notification
  • If the number of people count is zero then the device will send a "room is empty".

Reset the counting value

Use Simplicity Connect Mobile Application

Connect to the device

Follow the below steps to test the example with the Simplicity Connect application:

  • Open the Simplicity Connect app on your smartphone and allow the permission requested the first time it is opened.

  • Find your device in the Bluetooth Browser, advertising as People Counting, and tap Connect. Then you need accept the pairing request when connected for the first time. After that, wait for the connection to be established and the GATT database to be loaded.

    Note: The pairing process on Android and iOS devices is different. For more information, refer to Bluetooth security.

    EFR32 Connect App EFR32 Connect App EFR32 Connect App

Read/Write characteristics

The parameters of this example application can be easily configured via BLE characteristics. Values for the characteristics are handled by the application as ASCII strings. Tap on the main service to see the available characteristics.

Read:

Push the read button to request the value of a characteristic. (See ASCII fields.)

Write:

For setting a parameter select a characteristic and tap on its write button. Type a new value in the ASCII field and push the Send button.

People entered so far count People count Upper threshold Lower threshold
- Read to get the current total people entered count
- Write 00 00 to reset total people entered count		 - Read to get the current people count
- Write 00 00 to reset people count		 - Read to get the current upper threshold setting
- Write to set upper threshold settings		 - Read to get the current lower threshold setting
- Write to set lower threshold settings
IR threshold Hysteresis Notification status Room capacity
- Read to get the current IR threshold setting
- Write to set IR threshold setting		 - Read to get the current hysteresis setting
- Write to set hyteresis setting		 - Read to get the current notification status setting
- Write to set notification status setting		 - Read to get the current room capacity setting.
- Write to set room capacity setting

Report Bugs & Get Support

To report bugs in the Application Examples projects, please create a new "Issue" in the "Issues" section of bluetooth_applications repo. Please reference the board, project, and source files associated with the bug, and reference line numbers. If you are proposing a fix, also include information on the proposed fix. Since these examples are provided as-is, there is no guarantee that these examples will be updated to fix these issues.

Questions and comments related to these examples should be made by creating a new "Issue" in the "Issues" section of bluetooth_applications repo.