Tavanyar is a system which detects and evaluates physical therapy exercises automatically using motion tracking devices. This project consists of two parts: a piece of hardware and some kind of user interface. This code is the hardware-side of the project.
Two-way communication between hardware and user interface is made possible via bluetooth device:
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Hardware -> User interface:
Hardware can send 25 samples per second to the user interface. Each sample consists of the acceleration towards x, y, and z axes of each device obtained by accelerometers, and the angular velocity around x, y, and z axes of each device obtained by gyroscopes.
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User interface -> Hardware:
User interface can send commands to the hardware and configure the system. It can pause and resume sending data, and also specify the number of motion tracking devices being used.
The hardware consists of:
- One Arduino Uno as micro-controller
- Multiple (currently 2) MPU-6050 modules as motion tracking devices
- One HC-05 module as bluetooth device
- Clock frequency: the standard mode (100 KHz)
- Uses software serial protocol for debugging
- UART serial protocol standard: 8N1
- UART serial protocol baud rate: 38400 bps
- Accelerometer:
- Full-scale range: +/-8 g
- Sensitivity: 4096 LSB/g
- Low pass filter:
- Frequency: 5 Hz
- Delay: 19 ms
- Output rate: 1 KHz
- Gyroscope:
- Full-scale range: +/-1000 dps
- Sensitivity: 32.8 LSB/dps
- Low pass filter:
- Frequency: 5 Hz
- Delay: 18.6 ms
- Output rate: 1 KHz
- Sampling:
- Frequency: 25 Hz
- Divider: 39
- Clock reference: x axis of gyroscope
- Current consumption: 3.8 mA
- Uses digital input/output pins D13-D4 as address pins
- Uses 0x68 I2C address for the module under communication and 0x69 I2C address for other modules
- Name: TAVANYAR
- Password: 123456
- Uses software serial protocol for communication
- UART serial protocol standard: 8N1
- UART serial protocol baud rate: 38400 bps
- role: slave
It is assumed that MPU-6050 modules are calibrated, and the corresponding calibration offsets are fed into the system as well, all before running the sketch.
See this link in order to calibrate MPU-6050 modules and obtain calibration offsets: https://github.com/melikabarzegaran/mpu6050-raw-calibration
It is assumed that HC-05 module is configured before running the sketch.
See this link in order to configure HC-05 module: https://github.com/melikabarzegaran/hc05-configuration
We use 2 MPU-6050 modules with ASCII output format in the system, for the sake of simplicity and easy debugging. For such a system, according to the table below, 38400 bps would be enough as serial baud rate. Consider raising serial baud rate or shifting to binary output format when using more than 3 MPU-6050 modules.
| 9600 bps | 19200 bps | 38400 bps | 57600 bps | 74880 bps | 115200 bps | |
|---|---|---|---|---|---|---|
| binary output format | 1 | 3 | 6 | 9 | 12 | 19 |
| ASCII output format | - | 1 | 3 | 4 | 6 | 9 |