MCU

The project is based around Seeed Studio XIAO ESP32C3 development board. This mcu board was chosen for the following reason.

1) Small and lightweight design making it pet friendly

2) Integrated BLE capabilities of the ESP32C3 chip

3) On board LiPo battery charging circuitry

4) Rich peripherals including I2C

5) Low price

IMU

The project uses the MPU6050 IMU. This was chosen for the following reasons.

1) 3-Axis Accelerometer and Gyro Sensor on board a single package 

2) Readily available libraries.

3) Supports low power modes.

4) Cheap

The project is powered by a single LiPo cell.

Since the device is not continuously sending data and all it is doing is acquring the data of the sensor. The device thus has a long battery life.

The final cost of the product came out to be $13. Which can be further reduced by creating a single PCB.

Usage 

1) Put the collar around the pet's neck and turn on the device

2) Whenever you want using any BLE app (BLE Scanner(Connect & Notify ) ) recommended, by the push of a button the device will tell you the total time the pet had been active.

3) Charge the device using the USB C port on the collar.

Future Improvements

1) Right now the project uses a generic BLE app. Creating a custom app will enhance user experience.

2) Creating a single small PCB to house all the components will reduce the size and cost of the overall product.