Open Turret

An open sourced highly accurate pan-tilt system for anything that needs to be panned and tilted!
My goal for this project is to make a precise pan tilt mechanism that is accessible for everyone. The hardware is still quite experimental, but I hope to refine it and release build instructions soon. Feel free to contact me if you are interested in contributing, I will happily provide further build details.

To-Do

• Hardware
  • Add holes for removing bearings from parts
  • Make wiring rotation continuous (implement slipring)
  • Add tripod mount
  • Fix rigidity of pan axis
  • End-stops for tilt axis calibration
  • Pan Calibration Method
  • Rotary encoder on steppers for more positional feedback
  • Compass and accelerometer for positional feedback and calibration\
• PCB
  • Replace Q1 with two transistors - more accessible; less footprint specific
  • Just one oscillator for motor drivers
  • Just one ADC voltage divider
  • Correctly ground oscillator
  • SPI signal quality?
  • Buck converter noise filtering
  • Input power noise filtering (FB)
• Document Hardware
• Test load capacity and stability
  • Design large-scale version
  • Design slower much more precise version
• Explore using the Pi Zero or Wireless integrate electronics below tilt axis
• Get joystick to control motors
• Make easy stepper coding GUI
• Add zoom camera assembly
• Test whether the laser needs to be focussed to burn

Code To-Do

• Add skipped step / stall error feedback
• Add tilt axis to all implementations
• Refactor I2C event methods
• Shutdown & Startup motion method
• Add config file support
  • Save settings changed in GUI to remember configs
  • Restore defaults option

Required Specifications

• Better than 0.1º accuracy in both pan and tilt axis
• 360º continuous pan and 135º tilt in either direction
• Support weight of a laser diode
• Have a standard mounting interface
• Be as quiet and cheap as possible
• Entirely made of off-shelf or 3D printed parts
• Safety Measures
  • IR Detection
  • Radar movement detection
  • Short Pulse duration
  • Guiding laser
  • Alert before firing
  • Kill switch
• Decent speed (~36º/s)
• Targeting System
  • Manual (joystick)
  • IR Laser guided
  • Sound Guided
  • Image guided
• On-board Status Display

Milestones

• Implement joystick control of two axes and laser
• Successfully move both axes with >=0.1º precision
• Implement full system functionality including safety measures
• Implement an automated detection and firing software

Working Software Modes

• Full Manual: Control the turret and laser with a joystick
• Laser Guided: Autonomous Laser guided aiming of turret
• Sky Tracking: Use online data to track stars, planets, satellites, and air traffic. (For telescopes NOT lasers)

New Software Modes Ideas

• Autonomous targeting and firing by means of image recognition
• Laser shape drawing mode
• Autonomous targeting and firing by means of acoustic triangulation

Parts

• 2x NEMA17 Stepper Motors 0.9º 4.2 kg/cm
• 2x TMC2209 Stepper Drivers
• Joystick
• 1W Peak Laser Diode
• Bearings
• Axle Rods
• Various 3D Printed Parts
• Timing Belts
• Nuts n' Bolts

Credit

Thank you to the following resources for making this project possible.

• Gamepad library by Piborg - https://github.com/piborg/Gamepad
• Skyfield library
• ESA, 1997, The Hipparcos and Tycho Catalogues, ESA SP-1200
• NORAD
  • CelesTrack database - https://celestrak.com/NORAD/elements/active.txt
• NAIF SPICE kernel 'de440s.bsp'
• The OpenSky Network, http://www.opensky-network.org