I hope you will be patient with me, as this is my first project.
I’m trying to build a star-tracking platform for astrophotography. I need to develop a rotation of 15 degrees per hour. I have the mechanics figured out, and will be rotating a 1.5 kg load (camera and lens) at the end of a 15 cm rod, requiring 22.5 kg.cm of torque.
I was going to drive this starting with a 0.5 rpm motor through a series of gears stepping down by 720 times to the required rotation rate. But I realized that the motor would actually be running internally at several thousand rpm, which seemed like overkill.
Now I’m thinking of running a NEMA 14 stepping motor rated at 1.4 kg/cm torque. I’d still utilize a series of gears, both to magnify the torque and to speed up the stepping rate to smooth out the motion. If I could achieve a 32x rate of microsteps on a 200 step/rotation motor, the would be 6400 steps/revolution. To match the stars, that’d be one revolution PER DAY, which would be 6400 steps/24 hours or 0.074 steps/second. If I could adjust the gear ratio by 1:135, that would be 10 steps per second, which might suffice for smoothness (and also provide plenty of torque!).
I have an Arudino Uno on hand that I have managed to program (at a workshop last summer).
I was wondering if something like the RB-Elf-120 (Motor/Stepper/Servo shield kit for Arudino), along with my Uno and a power supply, is all I need to control the stepper motor.
Any assistance you could provide this novice would be appreciated.
- Chris