"Why, what is a seer? A man who with luck tells the truth sometimes, with frequent falsehoods, but when his luck deserts him, collapses then and there." - Iphigenia in Aulis 955
Calchas is a project for automotive driving data collection. The hardware consists of a few sensors on a custom board mounted to a Raspberry Pi. The data collection is driven by calchas-recorder.py program, stored on the SD card, and controlled through buttons and dip switches. The calchas-analyzer can import recordings from the Raspberry Pi to the desktop and run analysis on the data.
Each sensor collects timestamped data. The system clock is synchronized to the RTC during boot time. This guarantees that the timestamp each sensor generates is consistent.
| # | Component | Comment | Connection | /boot/config.txt |
|---|---|---|---|---|
| 1 | Raspberry Pi Camera | Camera v1, 5MP | MIPI CSI-2 | gpu_mem=128 and disable_camera_led=1 |
| 2 | Adafruit CSI Cable Extender | Makes swapping the camera easier | MIPI CSI-2 | |
| 3 | NEO-7M Mini GPS | With external antenna | UART (GPIO PIN 14, 15) | |
| 4 | DS1307 RTC | Consistent timestamps without NTP sync or after power cut | I2C (GPIO PIN 2, 3) | dtoverlay=i2c-rtc,ds1307 |
| 5 | GY-521 MPU6050 | 3-Axis Acceleration Gyroscope 6DOF; AD0 PIN set to high changes default address 0x68 to 0x69 | I2C (GPIO PIN 2, 3) 0x69 | |
| 6 | SDD1306 OLED | 0.96" 128x64 Monochrome | I2C (GPIO PIN 2, 3) 0x3c | dtparam=i2c_arm=on,i2c_arm_baudrate=400000 |
| 7 | OLED Menu | Switch to previous (left) / next (right) menu screen and toggle screen mode (middle) | GPIO PIN 17, 27, 18 | |
| 8 | Dip Switches | 8 switches to control the program | GPIO PIN 6, 12, 13, 16, 19, 20, 21, 26 | |
| 9 | Stop Recording | Hold 2sec to stop recording | GPIO PIN 25 | |
| 10 | Shutdown Button | Shut down the Raspberry Pi gracefully | GPIO PIN 5 | dtoverlay=gpio-shutdown,gpio_pin=5 |
| # | Activate | PIN | Comment |
|---|---|---|---|
| 1 | Start recorder on boot | GPIO 12 | |
| 2 | Display | GPIO 6 | |
| 3 | SystemInfo | GPIO 13 | Default 2Hz |
| 4 | PiCamera | GPIO 19 | Default 1920x1080 @10fps |
| 5 | Webcam | GPIO 16 | Default 1280x720 @10fps; USB Webcam through OpenCV |
| 6 | IMU | GPIO 20 | Default 5Hz |
| 7 | GPS | GPIO 26 | Default ~5Hz (unreliable) |
| 8 | unused | GPIO 21 |
systeminfo.csv: timestamp,system_cpu_percent,system_cpu_times_percent_system,system_cpu_times_percent_user,system_cpu_times_percent_idle,system_cpu_temp,system_loadavg_1,system_loadavg_5,system_loadavg_15,system_virtual_memory_percent,process_cpu_percent,process_cpu_time_system,process_cpu_time_user,process_mem_rss_percent,process_mem_vms_percent,disk_percent
picam.csv: timestamp,frame_num,frame_type,frame_size,video_size
picam.h264: Raw H264 stream
webcam0.csv: timestamp,frame_num,frame_size
webcam0.avi: MJPG format
imu.csv: timestamp,gyro_x,gyro_y,gyro_z,acc_x,acc_y,acc_z,rot_x,rot_y
gps.csv: timestamp,longitude,latitude,altitude
TODO