Quote:
Originally Posted by ChrisV
Damien
Thanks for this. I've been mulling over building a DC motor or stepper controlled focuser. Looks like the time to do it. But the computer interface bit of arduino code - are they for a meade focuser ASCOM interface, or something else?
Chris
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Hi Chris,
It works with the Meade Classic focuser Ascom and I've tested it on Nebulosity 4 and BYEOS 3.1.
In the Arduino code, I used the Meade protocol commands for the focuser and the Ascom driver uses these too for the Classic LX200. It's a very basic implementation of Ascom. So if you serially send the Arduino a ":F+#" from your computer, (9600,n,8,1), the focuser will start to travel outwards. Then send the Arduino a ":FQ#" to stop the travel and put a brake on the motor.
The commands the Arduino looks for are, (without quotes):
":F+#" travel out
":F-#" travel in
":FQ#" stop travel
":F1#" speed 1
":F2#" speed 2
":F3#" speed 3
":F4#" speed 4
Can be tested with a basic Serial program. (Hercules)
The speeds can be set to whatever value is best for your focuser.
I'm going to experiment in the Windows app, as I have a "centre the focus travel" button which is a timed function. Put the focuser in home position all the way in and then travel out and time it for a half way, put that time count in the code. I made it a little less than half as if the button gets pressed twice, it will almost be a full travel of the focuser.
Also to have a counter, not sure if it will be accurate enough. Realise it can't be precision with out some sort of encoding but with the braking implemented, it will be interesting to see if it could save a couple of values and then use later. For example on a night use eyepiece for a while, switch to camera and select a preset that gets you in the ball park for the camera.
But positioning is really for steppers and motors with encoders. We'll see what happens.
Cheers,
Damien