xtarke / solartracker

solarTracker

This application tracks the sun using NREL's Solar Position Algorithm (SPA) (not include in the repository). User interface uses MQTT publish/subscribe.

Prerequisites

• A BeagleBone black running Debian 9.3.
• PRU development files
• Mosquitto c++ devel files
• Mosquitto broker running in BeagleBone
• A serial GPS with NMEA string format
• A solar tracker with two stepper motors: Azimuth and Zenith

MQTT USer interface commands:

• Commands (to publish):

  • "solar/cmd": changes application mode

    • "0" -> Solar tracker activated
    • "1" -> Manual
    • "2" -> Turn off system. Azimuth and Zenith axis go to "home position"
    • "3" -> Calibration mode.

  • "solar/cmd/azrepos": reposition of Azimuth axis in pulses. Hardware max/min angles are proteced

    • Value lower than zero rotates clockwise
    • Value higher than zero rotates counterclowise
    • Only works in Manual mode

  • "solar/cmd/zerepos": reposition of Zenith axis in pulses. Hardware max/min angles are proteced

    • Value lower than zero rotates clockwise
    • Value higher than zero rotates counterclowise
    • Only works in Manual mode

  • "solar/cmd/zesethome": Move Zenith axis (pulses). NO HARDWARE PROTECTION.

    • Value lower than zero rotates clockwise
    • Value higher than zero rotates counterclowise
    • Only works in Manual mode

  • "solar/cmd/azsethome": Move Azimuth axis (pulses). NO HARDWARE PROTECTION.

    • Value lower than zero rotates clockwise
    • Value higher than zero rotates counterclowise
    • Only works in Manual mode

• Informations: (to subscribe):

  • "solar/gps/status": current GPS status (updated updated every 1 second)
  • "solar/az": current SPA Azimuth angle (updated updated every 1 second)
  • "solar/ze": current SPA Zenith angle (updated updated every 1 second)
  • "solar/gps/longitude": current GPS longiute (degress) (updated updated every 1 second)
  • "solar/gps/latitude": current GPS latitute (degress) (updated updated every 1 second)
  • "solar/gps/elevation": current GPS elevation (m) (updated updated every 1 second)
  • "solar/debug": CSV format az,ze,gps status, current time ((updated updated every 5 minutes)
  • "solar/norm": Azimuth Zenith AzPulses ZePulses (updated updated every 1 second)
  • "solar/sunrise": SPA sunrise time
  • "solar/sunset": SPA sunset time

Hardware notes

• BeagleBone pins: (ALL 3V3. Use correct voltage drivers)

  • I2C Interface for Magnetometer, termometer and barometer

    • P9.19 - I2C_SCL
    • P9.20 - I2C_SDA

  • Serial (UART) for NMEA GPS

    • P9.24 (TX) -> GPS (RX)
    • P9.26 (RX) -> GPS (TX)

  • Stepper interface: Internal Sitara PRU

    • P9.27 (PRU) -> Pulses to azimuth driver
    • P9.28 (PRU) -> Pulses to zenith driver
    • P9.29 (PRU) -> Azmith direction
    • P9.30 (PRU) -> Zenith direction

Notes about last version

• Updated:
  • Using Debian 9.3 now instead of ArchLinux
  • PRU uses uio_pruss and bone kernel
    • Linux beaglebone 4.9.76-bone9
  • Capes using /sys/devices/platform/bone_capemgr/slots are no longer suported
  • DTS are loaded in /boot/uEnv.txt
    • additional custom capes
      • uboot_overlay_addr4=/lib/firmware/BB-UART1-00A0.dtbo
      • uboot_overlay_addr5=/lib/firmware/EBB-PRU-xtarke-00A0.dtbo

Links:

- https://github.com/beagleboard/bb.org-overlays/
- https://github.com/cdsteinkuehler/beaglebone-universal-io
- https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
- https://github.com/RobertCNelson/dtb-rebuilder