Astrophotography motorized tripod that tracks objects on the sky as earth rotates. DIY el-cheapo.
3D printable parts fit 3 small step motors with M6 threaded rods as linear actuators for each of 3 legs of a cheap camera tripod "Vanguard VT-528A".
Motors are controled by a 3D printer motherboard "SKR 1.3" with Marlin firmware (g-code) powered from USB lithium battery. When all 3 motors are powered, motherboard draws about 2A, so 5V/10Ah battery can last for about 5h.
Simple python code is used to stabilize the picture. Code works without any knowledge of star/planet positions, time, geolocation or hardware geometry (tripod lengths and angles).
Usage:
Place tripod and set motor actuators to a position from which each leg has enough stroke to shorten or lengthen for tracking objects.
Run "./keyboard.py" or "./joystick.py" code. Motors will be driven to XYZ = 0,0,0 position which considered as initial position.
Manually point telephoto lens to any object on the sky, tighten it mechanically and apply maximum zoom.
Use keys Ins/Del, Home/End, Page UP/Down or LEFT JOYSTICK X/Y and RIGHT JOYSTICK Y and SHIFT or GREEN "A" BUTTON to center object in view. Those control change length of each of 3 tripod legs. Keys without SHIFT or GREEN "A" BUTTON make length change in steps of 0.1 mm, Keys with SHIFT or GREEN "A" BUTTON do it in steps of 1 mm.
When object is in the center, press SPACE or LEFT TRIGGER. Machine starts "learning".
As earth rotates, object moves from the center.
Use Ins/Del etc. keys or JOYSTICK to bring object to the center. When object is in the center again, press RETURN or RIGHT TRIGGER
Machine will "learn" user's centering and keep centering in the same direction.
If object still drifts slowly from the center, bring it mantually to the center and press RETURN or GREEN "A" BUTTON again. Centering can be repeated any number of times and it should refine.
BACKSPACE or RED "B" BUTTON cancels manual centering done after the last RETURN or RIGHT TRIGGER. After BACKSPACE or RED "B" BUTTON, motors wind back to position in the direction learned from last RETURN or RIGHT TRIGGER.
If long time has passed since last SPACE or LEFT TRIGGER or camera is pointed to another object, press SPACE or LEFT TRIGGER to start new learning and repeat manualy centering and pressing RETURN.
ESC or BACK BUTTON returns motor to 0,0,0 position
0 or START BUTTON sets current position as 0,0,0
Press LEFT BUMPER and RIGHT BUMPER at the same time to shutodown RPI (joystick.py only) so poweroff can be done clean.
Happy star tracking
