Hi Everyone, first post here! I’m hoping someone can help me out. I’ve being doing my fair bit of research and I’ve been having a hard time figuring out a best answer for which type of motor I would need (stepper, dc motor, servo…) I’m building a sort of Rube Goldberg machine. The part of the machine I’m hoping someone can help me with is I’m having a soccer ball roll into a bucket and I need a motor to rotate the bucket and have the ball drop out and then rotate back waiting for the next ball. Some notes that may be important are the machine will always be plugged in and on, and it will be used 20+ times a day. I’m hoping to find something that’s cost effective (I’m working on a tight budget) and that will not be a huge power draw. What type and size of motor would you suggest for this application? It will be controlled with an arduino uno or raspberry pi I haven’t decided how far I’m going to take this project yet. Thanks in advance for any help anyone can give me!
Normally you would use a gravity-based device to automatically rotate the bucket rather than an electric motor. If it’s just a motor, it would need to somehow “know” when there’s a ball in the bucket (button perhaps?) which activates the motor. Once the ball drops, the button would no longer be pressed, and a spring could return it to its initial position. Note that there are also many mechanical devices which offer intermittent motion. If you can provide a drawing of hte setup (and indicate size, as well as the direction of gravty) we may be able to offer additional insight, and perhaps suggest products.
Thanks for the quick reply! I’ve put together a simple drawing I hope it’s enough to get my point across. Sorry for the crude drawing. So basically this setup will be at the beginning of the larger “machine”. A ball will be in the bucket at ready waiting for someone to hit a button which will start the motor to turn the bucket and have it roll out onto a track. There will be pressure on the motor shaft because of the weight of the ball so that’s why I was concerned with using a stepper motor because it will be drawing power constantly even when it’s at rest. The size of the ball is approx 8.5" in diameter. I’m hoping to find a motor that will turn the bucket once the button is pressed, wait x amount of time for ball to roll out and then return to original position in anticipation of the ball coming back.
Thanks in advance!
If you put the pivot off-center and use a spring, the bucket will stay upright unless there is a load in it, at which point it will pivot until the load falls out, and the spring returns it to its original position. No motor or electronics needed.
So the problem there is that there will always be a load in it. The ball will remain in the bucket when the machine is at rest, waiting for the button to be pushed. That’s the start of the machine. That’s what kicks it all off.
Since positioning is important, and you need to have it start electrically, you would need:
]Servo motor with good torque robotshop.com/en/servo-motors.html /:m]
]Microcontroller (to be programmed) robotshop.com/en/microcontrollers.html/:m]
]Button robotshop.com/en/contact-sensors.html/:m]
]Power supply robotshop.com/en/power-systems.html/:m]
Note that servo motors are not meant to be run 24/7, and in regards to torque, you need to account for worst case scenario (when the ball is in the bucket at 90 degrees)
You would also not put the weight directly on the servo motor’s shaft. Consider a power gearbox: robotshop.com/en/servocity-t … servo.html
It would be up to you to program a microcontroller (you indicated Uno which seems good) to read the button input and send the appropriate sequence of commands to the servo. A Raspberry Pi is likely overkill for such an application.
Now when you say the servo is not supposed to be run 24/7 does that include just having power to the motor even if the bucket is at rest? Would the power need to be cut to the servo while the machine is not in use?
If the servo has no load at all, it should not generate much heat, but should still not be left plugged in. Servos tend ot have a duty cycle of only around 25%. If the machine is not being used, power should be cut.