Battery Free Electric Focuser.
Since I started to webcam image, one of the greatest sources of irritation
has been focussing. It's hard enough to focus on a planet without the scope
wobbling all over the place every time you touch the focussing knob.
Well
here is a solution I found one day while surfing the net. A battery free
electric focuser. Oh, and it's cheap to make too. How on earth, I hear you
say, can an elecric focuser work without batteries? The answer, when you
generate your own electricity using one servo to drive another servo.
One to act as a motor the other is the generator / remote focussing knob.
I have used this method to focus for about nine months now and it's
very easy to use, quite intuative and very effective. Here's what I did...
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Step One...You need to purchase two servos. The cheaper the better. |
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Step two...Take the servos apart (the picture only shows one servo). |
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Step three...Remove the electronics from the servo. You don't want this bit. Notice the white gear with the rectangular slot. The potentiometer was slotted into this gear. You will need to remove this gear for the next step. |
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Step four...There is a notch in the gear has to be removed. You need to remove the notch, to allow the gear to spin full circle. I recommend you use a hand file to do this. It is possible to use a stanley knife but this needs to be done with great care as the knife could easily slip. You do this at your own risk. |
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Step five...Connect the teminals of the motor to your cable. Here I have used telephone cable (four wire). I've doubled up the wires in order to use them all. You can use any cable you like.If you use more than one wire per terminal, make sure you use the same colours at both ends. If the servo is hard to turn then you have a short circuit somewhere. |
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Step six...Repeat the steps for the other motor and in step five, connect
the second servo motor to the other end of the cable.
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Step seven...Fix it to you telescope focuser. I used surplus gears from
an old printer and some bent metal.
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