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I saw the arduino boards sitting on the shelves at Radioshack and I figured I would try to make a focuser controller for the motor focuser I bought a few weeks back. This is mainly due to that the 100ft wires were too flimsy to last and secondly that I can then precisely control the focus, even without a focuser program.
The core of the focuser is an arduino uno with the arduino motor shield on it. The controllers costed $70. It would be powered by 6 D Cell batteries for 9V to the motor. 9V is used since the JMI focuser that it will be controlling is powered by a 9V controller. Finally the 9V supply is switched. The switch has an LED to indicate if it has power.
I designed this one such that the top can seal. The Dcells will give a long lasting power supply to it and i can keep it sealed.
The Arduino is over to the side with a hole in the lid for the USB cord. A 6 pin RJ11 jack is wired to match the motor power control on the JMI wire.
I implemented the controller such that it will be ASCOM compatible. It tries to use the duration of the focuser's movement as the position but if it fails accuracy testing I'll make it a relative controller. As of this moment i'm having trouble moving the ascom driver to my netbook but I'll figure that out. I just hope it clears up tonight so I can use it.
If the whole package is successful I'll design a smaller version of the controller using a 9V battery and to allow an external power supply.
Total cost of the system:
- 4slot Dcell : ~$4
- 2 slot Dcell: ~$2
- enclosure: $8
- Arduino uno: $37
- Arduino motor shield: $30
- lighted switch: $2
- wire stock: $4
- 6 pin socket: $10
total is about $117, about 70% the cost of JMI's controller. Its a fun learning experience for me though. My controller doesn't have the same amount of features that the JMI one does but its enough to accurately focus.