This surplus camera az/el device turned out no where near strong enough to swing a good antenna. Even a tiny UHF made from wood and light hollow aluminum rods barely worked :) Just not enough torque. I have another one with gearmotors and servo feedback that was the final working rotator for a nice big quad uhf beam.
This is the only one thing I'm afraid of - the torque... I use the same nema engines like you and I think I will have to deal with the torue problem too
A few issues. One, I wouldn't use a stepper motor. Its inductive load pulsed by a stepped driver shouldn't interfere with VHF or UhF; it will be problematic for HF signals. Also, a Nema 17 doesn't have the torque required for a small array like a Leo pack. However, using one with a planetary gear set would work. By using a stepper, you now need to home it. You also would have to close loop it to know if you had missed steps. Trinamic drivers would work, but that complicates things. It will also be back drivable, so you are wasting current having the steppers powered on all the time. The conventional DC motor with a potentiometer is a more straightforward system. If you were hell-bent on this type of system, a Nema 23 clear path would work better, but those motors are pretty spendy.
You are correct on all counts :) This camera mount would barely work with the smallest, lightest UHF antenna I could make out of hollow aluminum tubes and lightweight wood ruler. I have a later video of a much better rotator using dc gear motors in a servo arrangement with feedback pots. That one can swing a hefty x-quad UHF array.
Oh no this one is not very good at all - this is attempt #1 using a camera az/el platform from a surplus store, but it is too weak to move much of any practical antenna. I made one small very light UHF antenna and it did not work very well so went on to a commercial quad antenna and the rotator in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-3mtySzLX-5Q.html
This camera az/el mount turned out to be very weak and could barely swing a tiny UHF antenna made to be as light as possible. The Yeasu G-5500 is widely used for ham satellite work.
I'd like to ask you a question. I want to receive two-channel PWM through atmega328p and then control two stepping motors. How to write the program framework? I used the acelstepper library, but there are some problems. I'd like to hear from you. thank you.
two-channel PWM like used for radio control servos? Here is a well documented project code that takes input from an rc receiver. create.arduino.cc/projecthub/kelvineyeone/read-pwm-decode-rc-receiver-input-and-apply-fail-safe-6b90eb Should not be hard to get the value from those pwm inputs to drive a stepper motor over any desired range of motion. Will look into it, is an interesting idea.
Just tested the above sketch read-pwm-decode-rc-receiver-input and it works really well - used two channel, input pins 4,5 with an arduino pro-mini 3.3v 8Mhz version - set calibration and it reads -100/+100% for both aileron and elevator controls from an old analog 72MHz rc set. Next I'll mash that up with the AccelStepper library and two motors.
Here's the video for the stepper motor controlled by RC pwm signals, link to the code is in the description: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0kXlILWAYKg.html
The camera AZ/EL mount came with stepping motors from the surplus store, it was made for the NEMA size and just use regular metric scriews. It was a surplus broken camera az/el latform from Mendelsons in Dayton which is now closed for business. The idea was to point an antenna at satellites which this turned out to be way too under-powered for even the lightest UHF antenna :)
Esto se deriva del firmware del controlador de rotador satnogs de hace dos años que tiene un enlace a su versión actual gitlab.com/cswiger/stepper_motor_controller_h2
