Finally gonna do something about dome automation

[KathyNS]

I sent off for a high-torque stepper motor, an Arduino, and a few other bits to replace the DC motor that drives my dome. They arrived in today's mail. It will take a bit of work to put it all together and write the driver for it, but hopefully soon I will be able to send the dome to a specified azimuth reliably.

The motor is smaller than I expected, but I did the math for the torque requirements and it should be able to handle the dome just fine. It has a big planetary gearbox on the end of the motor. As long as I ramp up the speed to avoid sudden starts and stops, I will be well within the torque limits. I calculate it will be about 49,000 steps for a full revolution, so I should be able to get 26 arcsecond pointing accuracy if I needed to. I'll happily settle for the nearest degree.

It comes not a moment too soon. Last night's imaging session was just too damned cold!

[Hillrat]

Cool! Hope you've taken into account the enormous snowbanks that manage to sit on seemingly impossible places down your way!!!

Was just out getting set up for tonight! If there was any breeze I'd say to heck with it. -25C, calm and clear. Plenty of humidity too!

[ghswen]

This might help with your dome driver:

https://github.com/ejholmes/Arduino-...Dome/Driver.cs

and another:

https://github.com/mahanmawadj/arduino-dome-driver

[CamelHat]

Good move!

Be careful about using the Arduino standard stepper library. I used it, and it reduced the torque by quite a bit compared to a simple driver written according to the stepper motor's specification. This was a while ago so I don't know if it is still around. Just in case.

I recommend defining a time line to step against, not to wait a delta and then another delta because those errors accumulate.

You can use C++ but I never found the need for that, the C-like .ino language works fine and is easy to use.

I presume you got an Arduino power shield to drive it because the amps provided by a 5 V USB port won't be enough.


Good luck!

[KathyNS]

Thanks, Gordon, I will check out those resources.

Henk, that little "Stepper Motor Driver Carrier" board in the envelope will handle the Arduino-to-motor interface. It takes a logic input plus DC power, and drives this motor directly.

[KathyNS]

Well, I am learning to program an Arduino. I thought I had seen the last of the C language years ago. No such luck: the Arduino uses a C-like language. I'm trying to remember its syntax peculiarities. Getting there. I think I have an idea how I want to structure the program.

[CamelHat]

Well, I am learning to program an Arduino. I thought I had seen the last of the C language years ago. No such luck: the Arduino uses a C-like language. I'm trying to remember its syntax peculiarities. Getting there. I think I have an idea how I want to structure the program.

Check out the examples, they are under one of the menus. You can browse the source code. That's the easiest way to get back on track.

[KathyNS]

Thanks, yes, that's what I have been doing.

I heard that the C developers had a bet going for how ugly a language they could develop and still have people buy it.