Stepper Motor + controller

[HK.Raymond.Tse]

Dear all,

Instead of buying focusing motor such as JMI or Robofocus overseas, can any stepper motor + 2 buttons (forward + backward direction) hand controller be found in HK ?

Thanks for comment.

Raymond Tse

[Chanlunlun]

Dear all,

Instead of buying focusing motor such as JMI or Robofocus overseas, can any stepper motor + 2 buttons (forward + backward direction) hand controller be found in HK ?

Thanks for comment.

Raymond Tse

Dear Raymond,

If you find one please tell me.

What you are looking for has been searched by me for years but still in vain.

The controller is easy to be built by oneself but stepping motor comes along with a nasty habit of having severe vibration and bad performance in low speed. You also need a gear box to reduce its speed by 100X ~ 300X. You have absolutely no chance of finding such gearbox in Hong Kong.

Hence, to make things more starightforward, just be adviced to buy a JMI.

Best regards
Chan Yuk Lun

[david_kmng]

Raymond,

You may try to buy a DIY kit in Ap Liu Street which costs $100.- It is very simple to build but there is a bug in the circuit. You may call me.

If you need a small gear reducer, particularly for using on telescope focuser, I suggest you to buy a planetary gear box from model shop. It is small enough and flexible to create different gear ratio. The price is about $80. But you may need to think about how to connect it to a stepper motor.

Also, if you look for small stepper motor, surplus shop in Ap Liu streets are selling some small and light stepper motor, for just $10. If you do not mind the looking of the motor, they shoudl be fine. The one is with some flexi-printing-circuit for connection. Also I tried one from Wah Fat, which is as small as 4 $10 coins stacked together. But the one I bought failed to work (and to identify the leads). If it works, it should be the ideal choice.

Finally, it depends on your imagination to put it to the scope, and isolate the vibration. Driving belt, rubber are good materials.

Regards,
David

[HK.Raymond.Tse]

Thanks for the replies.

I have bought some small motors from Ap Liu Street but have no idea whether they are DC or Stepper motors. Just motors with several wires and I have no ideas what the wires are for.

Orion has just put up an electronic focuser for some of their refractors (except their ED refractors) and reflectors at low costs. No mention what they are. See
http://www.telescope.com/shopping/produ ... ctID=54531

I guess they are just DC motors with fast-slow rates. May be useful to reduce vibration but certainly without the quality of recognising the relative positions as stepper motors do. Hence not useful for computer-aided autofocusing.

Raymond Tse

[elton]

From the outlook of the Orion electric focuser, it should be the gearhead DC motor.
Sometimes I have a doubt... in order to have the speed reduced alot, we use gear box, which will increase the output torque significantly also. Will this torque be so big to destroy the focuser when it came to the extreme positions?

[XR250]

FYI, this website has some stepping motor controller.

http://www.cpu.com.tw/kh/kit/motor/motor-1.html

[xiao]

[quote="HK.Raymond.Tse"]Dear all,

Instead of buying focusing motor such as JMI or Robofocus overseas, can any stepper motor + 2 buttons (forward + backward direction) hand controller be found in HK ?

Thanks for comment.

Raymond Tse[/quote]

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