Digital Setting Circles working with SkySafari

Wanna make a scope? Or better still, grind a mirror yourself. Or, you have some good tips in making a really useful accessory? This is the place to show what your hands can do...
geyes30
 
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Digital Setting Circles working with SkySafari

Postby geyes30 » Tue May 29, 2018 10:24 am

As part of my planetary scope build, I made DSCs for the scope. It uses one gyroscope and one rotary encoder.

Firstly, a large gear is fabricated using a timing belt (315 teeth) attached to a wooden disc that was carefully cut for the belt to fit over.
ImageEncoder Disc by Cyrus Beh, on Flickr

This mates with the encoder, which has a 16 teeth gear. The reduction ratio is thus 19.6875. This gives more than 40000 steps per circle.

A swing arm pivots and pushes the encoder onto the gear.
ImageSwing arm by Cyrus Beh, on Flickr

The spring pushes the swing arm. Pressure is firm, but not too much so. Otherwise, the movement of the scope will become bumpy, since you will feel the gears meshing.

A box destined for the trash heap was upcycled to serve as the holder for the breadboard, which in turn holds the electronics. A barrel connector delivers 12V power from the same battery that powers the cooling fan. This is down-converted to 5V using a Pololu step-up/step-down converter. Wiring is done with jumpers on the breadboard.
ImageBox by Cyrus Beh, on Flickr

A cabe gland (gray in picture above) was used to allow the encoder cable to be introduced into the box, without any chance of it tugging on the electronics. This prevents accidental disconnection.

Lastly, strips of velcro attach the box onto the scope body.
ImageVelcro-on Accelerometer by Cyrus Beh, on Flickr

Here it is in action:

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Airconvent
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Re: Digital Setting Circles working with SkySafari

Postby Airconvent » Tue May 29, 2018 1:45 pm

Nicely done! :)
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geyes30
 
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Re: Digital Setting Circles working with SkySafari

Postby geyes30 » Tue May 29, 2018 5:06 pm

Thanks! I should mention the cost of goods here:

Wood panel for cutting into disc - $6
Electronics: $10
Timing belt: $8
Encoder: $16
Various connectors: $8

Pretty cheap!

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Airconvent
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Re: Digital Setting Circles working with SkySafari

Postby Airconvent » Wed May 30, 2018 12:23 am

Building it - Priceless ! :)
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