v8kid
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| posted on 7/6/11 at 05:53 PM |
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Automatic Sturmey Archer PIC?
I'm toying with the idea of building an electrically assisted bicycle and am thinking of using a Sturmey Archer wheel to give 3 speeds.
The idea is if I set up 2nd gear for my cruising speed first will improve get away from standstill and 3rd will give a little boost when I'm
feeling super energetic.
Just to make it interesting I'd like the gearchange to be automatic but how to do it?
I guess i could use a pic and determine gear change up and down revs of the rear wheel for each gear but how do I actuate the gearchange mechanism?
As I recall the spring in the gearchange is quite strong would a stepper motor be strong enough? Can stepper motors be geared down easily to give more
torque?
Cheers!
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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rusty nuts
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| posted on 7/6/11 at 06:47 PM |
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Just pedal harder!
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rf900rush
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| posted on 7/6/11 at 08:19 PM |
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Could try to get a stepper motor with a lead screw type shaft (linear stepper motor)
Like these
Linky
You may be able to drive a piece of threaded studding and use the moving nut to push/pull the gear box linkage.
Hope that make sense.
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v8kid
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| posted on 8/6/11 at 07:22 AM |
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Excellent thanks that's just what I need
Cheers!
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
|
|
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