I would like to make an orrery, model of Solar system, as a hobby project. I've never worked with arduino, but have some experience with programming (java, java script..) and making lego robots
I would need 9 motors which would operate 9 ring shaped gears with diameters ranging from 10 cm to 70 cm. So I guess there is light load and high precision requirement.
I need advice in what kind of motor (stepper, servo, dc.. which brand..) would be best suited for this task (it would be nice if the noise level is low, too) and how to achieve precision over long period of time?
And what kind of board can operate those motors?
I will start tutorial on Udemy (do you recommend sth else?) and it is with Arduino Uno, but I would like to follow it with equipment that is suiting my needs for this project.
Perfect job for 28byj-48 stepper motors. Small, quiet, cheap, lots of steps per rotation. They do require four pins each for control, so 9 rings = 36 pins total. That calls for a Mega.
The mechanics are no doubt going to be the hardest part of this project.
wvmarle:
Perfect job for 28byj-48 stepper motors. Small, quiet, cheap, lots of steps per rotation. They do require four pins each for control, so 9 rings = 36 pins total. That calls for a Mega.
The mechanics are no doubt going to be the hardest part of this project.
Thank you. I really like the price of these But they seem to be very slow... 15 RPM. And I would be reducing their speeds through gears by factor of cca 5 to 20 for the outermost planets. And if I 'gear it up' I'm not sure if they could handle the load (which is mainly friction).
Do you have any suggestions for controlling accumulated error? I thought about placing hall effect sensor or optical sensor for determining rings full circle movement.
Juraj:
all planers and moons can move ovet gears with one motor.
I'm aware of that kind of mechanism, but I need planets to move independently because I want to skip to specific constellations in future without making all rotations....
munch15a:
very cool idea but no moons ?
...and that is the same reason I won't have any moons... And I would really love to have the Moon
As long as the steppers don't miss steps you should not have any error.
There is another problem though: when starting up you don't know where you are, and that alone means you need some form of "home" sensor. A slot with optical sensor, or a magnet and hall effect sensor or reed switch, a microswitch, something like that. That can double as feedback to reset your "home" on the fly.
Steppers are indeed relatively slow. I think I got to about 30 rpm with those steppers, but that was the limit indeed. Other steppers may be faster, but won't be speed monsters.
