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motors and arduino
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

motors and arduino

by waxaw on Thu Oct 12, 2017 1:16 pm

Hi,
I'd like to slowly turn up to 16 motors one rotation at a time and then stop. Can you tell me what type of motor is best for this I'm creating a simple installation of pods that rotate on a wall.

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 1:28 pm

If you want to go exactly one rotation, you need either a stepper motor or a motor with feedback.
https://learn.adafruit.com/adafruit-mot ... s?view=all

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Re: motors and arduino

by waxaw on Thu Oct 12, 2017 1:53 pm

Can I control multiple stepper motors with one arduino board?

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Re: motors and arduino

by waxaw on Thu Oct 12, 2017 1:55 pm

Or can you tell me which servo motors have feedback? Is it any motor other than continuous rotation motors?

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 1:55 pm

Yes, it is possible to control multiple steppers with an Arduino. How fast do they need to turn? Speed can be an issue with many motors.

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 1:58 pm

The guide above explains servo feedback. Most Continuous Rotation "Servos" do not have feedback.

We now carry the Parallax version which does have feedback
https://www.adafruit.com/product/3614

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Re: motors and arduino

by waxaw on Thu Oct 12, 2017 2:00 pm

I'd like them to go very slowly -- approximately one rotation per 5 seconds.

Can I control up to 16 stepper motors ? Also you have been so kind and patient. Thank you !

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Re: motors and arduino

by waxaw on Thu Oct 12, 2017 2:03 pm

do you offer one on one support for hire? I'm working on a project for a gallery in Boston.

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 2:13 pm

The motor shield can control up to 2 motors per shield. You can stack up to 32 shields to control as many as 64 steppers.
https://www.adafruit.com/product/1438

With more motors and high step counts, the maximum speed is limited. Using 16 200 step motors like this one: https://www.adafruit.com/product/324
your maximum speed would be about 3 RPM. That is one revolution per 20 seconds. If you can find some 48 step (7.5 degree step angle) motors, you should be able to get one revolution in about 5 seconds.

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Re: motors and arduino

by kcl1s on Thu Oct 12, 2017 2:25 pm

Cool project! For your control specs (one rotation and stop) I think a gear motor with shaft sensor to tell you when you have completed the revolution would be most cost effective. The sensor could be a microswitch with a cam or a light sensor with reflective surface or a magnet and a reed switch. If you only need one direction rotation you can get by with 2 Arduino pins per motor setup. One for the motor and one for the switch so you could get 8-10 setups max on an Uno or Metro (6 if you want to control speed - only 6 pwm pins). The Mega if you can find one could handle them all (15 with speed control). You will need transistors or mosfets for power control of the motors

Keith.

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 2:28 pm

Some 7.5 degree motors here. Some pretty reasonably priced.
http://www.electronicsurplus.com/motors/stepper
For use with the motor shield, look for motors with at least 10 ohms phase resistance.

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Re: motors and arduino

by kcl1s on Thu Oct 12, 2017 2:35 pm

Be careful with smaller steppers. They can loose steps (position) if near their torque limit and loose their orientation if that is important.

Keith

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Re: motors and arduino

by waxaw on Thu Oct 12, 2017 2:56 pm

Hi I noticed that this motor http://www.electronicsurplus.com/motors/stepper
has six wires and the shield only has five. Is there a work around?

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Re: motors and arduino

by adafruit_support_bill on Thu Oct 12, 2017 2:59 pm

Yup. Just ignore the 2 center-tap wires. You can leave them unconnected.

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Please be positive and constructive with your questions and comments.