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Topic: feasibility question: turning dc motor to servo? (Read 4 times) previous topic - next topic

dhenry

A bldc motor is an excellent rotary encoder.

ironbot

Thanks I'd study what rotary encoders I can get, by the way the photo shows the machined parts. They are from a very cheap wood to just test, I plan to after corrections (changing encoders, etc.) machine final design out of plastic for inside, and from outside it will be covered by fiberglass.




JohnHill

Maybe entirely off track but if you want to arrange for the motor to be able to move the arm but not the arm move the motor then you could use worm and wheel gearing.  This will also give a high mechanical advantage to the motor which could be smaller than otherwise required.  But you would have to think about how fast you want the arm to move etc.

GoForSmoke

Quote

But, I have no idea how to build a miniature brake. 


Use a small clamp and pencil eraser? It'd need a motor/servo to grip and release.


I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

ironbot

JohnHill,
Yes worm is good, and this is actually a neck, so it is necessary that it moves slowly.

GoForSmoke,
Well I'm not really sure I could use a pencil there. Also, if to use a servo to be a brake for a dc motor with the aim of making the dc motor function as a servo, then it seems to be better to forget that and use 1 servo from the beginning. I'm still looking if I can put my cnc machine to use for Arduino robot and create mechanical advantage so hopefully: use those 8$ dc motors, some cnc machined mechanics (may be a solenoid) and get a servo-mechanism for neck, which costs in whole less than a 15$ hs-422. This may be a closer formulation of my initial goal.

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