Automated Obsy Roof

[WbRaDy]

I thought i would put this up for anyone wanting any information on this observatory modification, there are other videos uploaded by a few people which i give thanks so i have followed in their footsteps and done the same, the parts required are very easy to source the most expensive being the chain at £25 for 5m but only 2.5m was required, i have posted links to the parts used and they was the cheapest i could find at the time so if anyone is wanting some information in the mean time please ask away..
08B-1 Roller Chain half inch pitch, £25.80
http://www.ebay.co.uk/itm/Dunlop-Btl-08B-1-Roller-Chain-Din818-7-British-Std-5Mtr-/131991390744?hash=item1ebb4cca18
3 x 08B1-11 Sprockets half inch pitch,  £1.97 each + £0.99 postage
http://www.bearingsrus.co.uk/4sr11
Motor speed controller , was purchased from Hong Kong but received in a week, £5.99
http://www.ebay.co.uk/itm/DC-30A-12V-SoftStart-Reversible-Motor-Speed-Control-PWM-Controller-PWM/201944328448?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648
Second hand wiper motor from eBay removed from a ford Ka 98/08, £7
All in all about the same price as a second hand garage door opener which was the other option but i had to basicly massacre it to make it work and not even sure if it would so this option was the best for me, the motor is moving a roof at 3m x 2m..the project will be finished shortly when a project box arrives to tidy all the cables and somewhere for the switch to sit, Thanks for watching....

YouTube

[Zakalwe]

That's a nice simple design.
All you need now is a couple of limit switches and an ASCOM interface

[saac]

Neat design and well executed, well done. 

Jim

[WbRaDy]

58 minutes ago, Zakalwe said:

That's a nice simple design.
All you need now is a couple of limit switches and an ASCOM interface

They went on 10 minutes after filming 

Thanks guys...

[steppenwolf]

I like that a lot and the design saves the requirement for a full chain loop - excellent!

[Zakalwe]

14 hours ago, wayne11 said:

They went on 10 minutes after filming 

Thanks guys...

I love it!

Would you mind sharing how you did these bits?

[WbRaDy]

No problem, again i cant take any credit for this at all, i found the video on you tube from someone called MrPragmaticLee, he used the setup on a lathe to prevent excess forward/backward movement...the same as us in a away...when i purchased the speed controller it was already wired up pretty much the same as he describes in his video except there is a "bridge" of wire that has to be removed, if you look at the diagram of the toggle switch and imagine a cable soldered from the top right to the bottom left, this has to be cut and removed, you will see this in his explanation...as for Ascom i havnt begun to set this up yet but finding it hard to do so anyhow, reason being the switch is a metre a way from my computer and as the roof is rigged with the two micro switches i cannot convince myself the need for Ascom, also i like to open the roof now and again to air it out so the need for the computer to be turned on just for that puts me off also.....never know on a rainy day though..

MrPragmaticLee

Edited July 24, 2017 by wayne11

[snowy911]

This is brilliant, I've been toying with the idea of adding a motor to the roof for some time, but hadn't found a solution that got me over the start line.  Ordered the controller already!

[WbRaDy]

Good luck mate, its so easy to do and a pleasure to use....my idea was to flick a switch and carry on with something else while its opening.......i tend to stand gawping at it..

[daz]

Excellent thread!!

I am (slowly) working on a similar project but will have full automation (eventually). I was thinking of a full loop of chain down both sides, but your solution looks very neat!

 

[Fellside]

Wayne11

Did you fit any sort of bearing in the top two Sprockets or do they just run metal to metal on there mounting screws. Looking at the RPM and the amount of use the roof will get in the UK they will probably last a while without bearings if lubricated.

Thanks for posting.

I`ve ordered my speed controller

[Fellside]

For anyone using INDI this looks like the way to operate the system remotely. Uses cheap USBRelays from ebay.

Ebay text mentions ease of use with Windows. Ascom drive should be a breeze.

https://github.com/magnue/indi_usbrelay2_roof

[WbRaDy]

Fellside metal to metal at the moment until i strip it down again which i will be doing when ive sorted the project box/switch out,  it is lubed up with silicone grease for trials at which time i will put a couple of nylon washers in there to reduce the friction, the bearings just added to the cost and for the amount of use should last me years without them..

Cheers

Edited July 26, 2017 by wayne11

[WbRaDy]

Quick update, first of all sorry for the above image, thanks to Photobucket im in the process of moving my images to another site so please watch this space, i have installed the switch and controller into a project box from RS components, i will update the video with the link for this, also removed the sprockets and put a nylon washer in between them and the back plate, re greased and back together again....power for this is 12v straight from the pier, i have decided not to hard wire it in for now but will look into this in the future...job done

Blanked image from above post..

Edited July 29, 2017 by wayne11

[MultumInParvo]

Just ordered up the bits, but unfortunetely cant see the images, could you repost?

Also, your track and wheels seem a lot simpler/cheaper than most I have seen on here which use the FH Brundle stuff meant for sliding gates, where did you pick these up?

As it is a track they sit in rather than on, do you get issues with leaves or other stuff getting in them?

How are these after a year or so in place and would you do anything differently on the build?

All the best,

Ian

[Fellside]

Hi Ian,

I used FH Brundle V form track and 6 wheels to match. My roof is quite heavy and leaves dont get in the way🙂 The V wheels sit on the track. FH Brundle  wheels are definatly the way to go just fit and forget.

Are you going to use the Ebay soft start. If so all I did was replace the forward and reverse switch with two relays. Touch wood it works well. I have added a limit swich at either end and also a magnetic switches that tells ascom where the roof is.

I used the Vauhall Wiper motor and it only takes about 4 Amps when running. The motor has two speeds. I have it set to the slowest. Also the soft stat is set to slowest speed. The problem with the Vauhall Wiper motor and most other types I have seem is that the output shaft is verry short, so fitting the pully can be a problem. The original design in this thread used two idler pullies and one fitted to the motor. I have only used one idler and one on the motor.

I may have the originl three pully picture, I will have a look.

Hope this helps

Graham

[MultumInParvo]

Hi Graham,

I went with the FH Brundle track and, suprisingly, they were cheaper than anyone, ebay included, and they had all the other bits I needed such as 3m of 12mm threaded rod, again cheaper than elsewhere.

Thanks for the pic, I guess I need to get myself some aluminium plate, missed that off my shopping list.

The bit I am most interested in is the automation of the system.  I am indeed using the one from ebay, and plan to control it with relays and limit switches.  Any photo's or diagrams you have of what you have put in, including the position sensors for Ascom would be really helpful.

I have a Raspi 3b+ on its way to me, and I am trying to find out about what relay devices are best as the ones I see vary wildly in price from a fiver up to £50, so any feedback here would be happily received.

This is the one that seems adequate to my mind:

https://www.ebay.co.uk/itm/8-way-8-Channel-DC-12V-Relay-control-board-relays-Module-For-AVR-ARM-Development/152240067348?hash=item2372371314:g:1l8AAOSwxblbPch-

Is there anything I need to consider about the types of switches and sensors? I know from other hobbies that microswitches and their actuator leaves can deform over time, so I'm a fan of non-contact methods like magentic contacts used in alarm systems, but not sure whether they are suitable here.

All the best,

Ian

[Gina]

Hall effect switches and little magnets are reliable, easy to use, small and not affected by damp.

[Fellside]

Ian

See pictures of my limit switches. They have been working with no problems or maintenance for just over a year.

Left-hand assembly is in the closed position. Blue magnetic switch is for indication only. The physically switch is wired in series with the close relay coil. That way it should stop the motor in the event of a software failure. If you use the magnetic switches to indicate to the software that the roof is closed then the software opens the relay. Thing could go wrong. I like a physically switch in the relay control circuit.

The right-hand switch is for open. (middle picture is with the roof open)There is an actuating skid at the other end of the moving part of the roof attached to it is the open position magnet. (shown in right-hand picture) This way both sets of switches are at the open end of the scope room and no wiring has to go the other end.

I use two relays on  a DragonFly to control the roof via Ascom from within software or scripts direct from the DragonFly.

What software are you going to be using to control the Observatory?

Regards

Graham

[Gina]

When I get round to doing it, I plan to drive my roof opening/closing motor with power MOSFETs so it's all semiconductor anyway.