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Pulsar Dome DIY Automation - fully functional at last!

Steve 1962

By Steve 1962
in DIY Observatories

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Steve 1962

Steve 1962

Posted
Posted

For a quite a while now, I've been working on using an arduino to control the azimuth and shutter operation of my four year old  2.2m Pulsar dome.

I've had a few versions of a working system up until now, but they've always used a standalone application to run them. However, over the past few weeks I've re-written the arduino code and Mahan Mawadj from Canada has very kindly written me an excellent ASCOM driver.

Here's a video of the system in operation....

The system uses 2 Nema 23 4kN stepper motors and M542 stepper drivers - one for the azimuth and one for the shutter.

The azimuth motor runs a drive cog around a CNC machine drive belt which is glued to the dome walls and the shuter motor uses the existing shutter string to open and close the shutter. 

The azimuth motor is mounted on a cheap TV swing and the shutter is mounted on a home made pivot - both are held in tension by bungee cord.

The system keeps track of the number of steps that the azimuth motor has taken from its home position (north) and uses this info to calculate the dome azimuth.

There are limit switches mounted at the Dome Home, Shutter Open, Shutter Closed and Shutter Locked positions....

.....and as can be seen, it works with the excellent SGPro.

At the moment, the system uses an umbillical cord comprising a 230V power lead and a USB lead, but the next step will be to make it wireless and battery powered.

Total cost for all the bits - less than £300.

Thanks for looking.

Steve

 

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PhotoGav

PhotoGav

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Congratulations, that is a triumph! As a fully paid up member of the Automated Dome Club, I love my auto-dome and the ease of imaging it affords is worth all the angst getting to a fully operational one-click (ish) system! I wish you lots of clear skies and stunning images to follow.

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sloz1664

sloz1664

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Hi Steve,

Brilliant result. All that hard work has paid off and it looks and sounds great.

I've started my Pulsar Dome automation project. I have completed the Dome motor assembly and acquired a motor for the shutter. I will be using the Levesdome software to manage the alignment. As I want to image through the these dark nights. It's all on hold till next spring.

 

Steve

 

 

Dome Motor.jpg

Shutter Motor.jpg

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Steve 1962

Steve 1962

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Thank Steve, Gav and Steve!

Quote

I love the sound of the motors ramping gently up to speed

Quote

and sounds great.

 I can't claim any credit for that - it's all done by the AccelStepper arduino library.

Quote

worth all the angst

"Angst" is the right word Gav - but we got there in the end..and it's been a great learning curve!! Looking forward to the dark winter nights now!

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  • 4 months later...
mhard26339

mhard26339

Posted
Posted
On 26/09/2016 at 08:43, Steve 1962 said:

For a quite a while now, I've been working on using an arduino to control the azimuth and shutter operation of my four year old  2.2m Pulsar dome.

I've had a few versions of a working system up until now, but they've always used a standalone application to run them. However, over the past few weeks I've re-written the arduino code and Mahan Mawadj from Canada has very kindly written me an excellent ASCOM driver.

Here's a video of the system in operation....

The system uses 2 Nema 23 4kN stepper motors and M542 stepper drivers - one for the azimuth and one for the shutter.

The azimuth motor runs a drive cog around a CNC machine drive belt which is glued to the dome walls and the shuter motor uses the existing shutter string to open and close the shutter. 

The azimuth motor is mounted on a cheap TV swing and the shutter is mounted on a home made pivot - both are held in tension by bungee cord.

The system keeps track of the number of steps that the azimuth motor has taken from its home position (north) and uses this info to calculate the dome azimuth.

There are limit switches mounted at the Dome Home, Shutter Open, Shutter Closed and Shutter Locked positions....

.....and as can be seen, it works with the excellent SGPro.

At the moment, the system uses an umbillical cord comprising a 230V power lead and a USB lead, but the next step will be to make it wireless and battery powered.

Total cost for all the bits - less than £300.

Thanks for looking.

Steve

 

Excellent job Steve, as the "other" Steve said, love the sound of the motors, it beats the clanking of the Pulsar chain driven system which is a bit noisy, at least on mine!

Regards

Mike

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  • 9 months later...
SnakeyJ

SnakeyJ

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Thanks Steve - Just looking at doing this for my own 2.2m pulsar and was originally thinking of using DC motors/wheels.    However, I really like the idea of a bonded CNC drive belt as this could serve dual purpose (drive and a rotary encoder) - Any chance you could post a few pics and comments on the belt and how you bonded this.

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Steve 1962

Steve 1962

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Hi Jake @SnakeyJ

I'll try and post some pictures tomorrow. You're absolutely right about the CNC drive belt acting as drive and built in encoder - my code relies solely on the number of motor steps per degree of rotation, - which is based on steps per belt tooth x belt teeth per degree - simples.

The belt was bonded using Gorilla Glue and was held in place with all of the household's clothes pegs until the glue had set.

Hope that helps - photos to follow!

Regards

Steve

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sloz1664

sloz1664

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4 hours ago, Steve 1962 said:

Hi Jake @SnakeyJ

I'll try and post some pictures tomorrow. You're absolutely right about the CNC drive belt acting as drive and built in encoder - my code relies solely on the number of motor steps per degree of rotation, - which is based on steps per belt tooth x belt teeth per degree - simples.

The belt was bonded using Gorilla Glue and was held in place with all of the household's clothes pegs until the glue had set.

Hope that helps - photos to follow!

Regards

Steve

I used impact adhesive. No need to clamp in place.

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  • 8 months later...

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