Gina's Observatory Roll-Off-Roof Automation

[Gina]

Progress (or lack of) so far then :-

1. Loop parts of roof anti-lift system will be screwed to the corner uprights of the fixed observatory framework.
2. I shall keep the storm lock-down latches and window bolts so won't need the linear actuator to bolt the roof closed.
3. Limit switches are well on the way to being sorted out.
4. Rain detector will be tested when we get some rain.
5. Spring to tension chain and limit force used to close roof, works well.
6. Push buttons on the control unit will provide local control - Open, Close, Abort.
7. May use coloured LEDs on front of control unit to indicate status - Open, Closed, Closed after rain detected, Fault, etc.
8. I plan to include RPi in the control unit box for remote control and feedback.
9. The bungee cord for pulling the window open seems to be loosing strength so I'm going for another solution with lever and spring.
10. The small chain pulley needs a thicker screw into the baseboard - current one is bending from the tension in the chain.

Edited August 4, 2019 by Gina

[Gina]

Rain overnight was detected by the rain detector - tick.  What I don't know yet is how soon the rain was detected after it started, because I was asleep when it started.

[pete_l]

56 minutes ago, Gina said:

What I don't know yet is how soon the rain was detected after it started

Watering can?

[Gina]

A watering can would contain polluted water but what I really need is real rain.  Anyway, there are very dark clouds gathering so a shower may be imminent.

[Gina]

Very dark clouds have gone again...

Been out to observatory and looked at positioning of limit switches.  Think I have it sorted out.  Now taking a break for breakfast

Edited August 5, 2019 by Gina

[Dr_Ju_ju]

Isn't it always the way, when you want rain, none comes.....

[Gina]

Never mind - plenty to do on the observatory that wants fine weather (though not too hot).

[Gina]

One limit switch installed and operating but not connected yet.  Nothing yet to connect it to, anyway. 

Small chain pulley unscrewed, brought indoors and centre hole drilled out to 8mm for an 8mm SS coach screw.  That won't bend!

[Gina]

After a lot of messing about getting the pulley aligned well enough and reconnecting the chain ends to the roof, I have succeeded in getting the chain drive working again.  Now need a break.  

[Dr_Ju_ju]

A small libation is called for.....

[Gina]

Yes, just had a nice cup of tea.  😀  Watching Countdown to relax.

Edited August 5, 2019 by Gina

[Gina]

Not sure I'm completely happy with the small chain pulley - may redesign it and print a new one.  A bit wider and deeper flanges with a bevel perhaps.  But not now, maybe later.

[Gina]

Looking at this photo, I think a slightly bigger pulley would be better, lifting the chain a bit higher above the motor board.  Another thing this photo shows is that the motor unit may not be quite at the right angle for the chain to the large pulley.  Something to investigate.

Edited August 5, 2019 by Gina

[Dr_Ju_ju]

Even though I love printed parts, for something like that, I'd be tempted to go for all metal, with over size penny washers'ish etc.....

[Starlight 1]

7 hours ago, Gina said:

Rain overnight was detected by the rain detector - tick.  What I don't know yet is how soon the rain was detected after it started, because I was asleep when it started.

Put a capacitor on it connet to bed you not be asleep for long.⚡

[Gina]

Motor unit position adjusted.

[Gina]

1 hour ago, Dr_Ju_ju said:

Even though I love printed parts, for something like that, I'd be tempted to go for all metal, with over size penny washers'ish etc.....

If I had my lathe working I could turn one.  OTOH printed parts are very strong.  I could use PETG rather than PLA for extra strength and durability.  The current one was printed in ABS.

Edited August 5, 2019 by Gina

[Gina]

I have a large ball bearing 50mm x 78mm x 18mm which I could use and cut down on the thickness of plastic the chain rides on.

[Gina]

Anyway, the current 70mm OD pulley is working adequately and I'm not looking for extra work - I have more than plenty already!!  Once I have everything working I might look at improvements.

[Gina]

Having moved the motor unit I found the chain had jammed and I've had to take it right off to clear it!!  It's going to stay off and the chain disconnected whilst I sort out the limit switches.  I need the roof as free to move by hand as possible as I'm having to move it back and forth to test the limit switches.

[Gina]

This job is NOT going to beat me!!!  Just a case of the impossible taking a little longer!

[Gina]

For anyone not knowing what I'm talking about, it comes from a maxim we had at work "The easy we delegate, the difficult we do straight away, the impossible takes a little longer".

[Gina]

Photos of limit switches in operation - two for roof closed and one for roof open.

Edited August 5, 2019 by Gina

[DaveL59]

11 hours ago, Gina said:

A watering can would contain polluted water but what I really need is real rain.  Anyway, there are very dark clouds gathering so a shower may be imminent.

could you not try with a small amount of distilled water, just as a test if rain doesn't co-operate?

[Gina]

Distilled water will not trigger the rain detector - this is a known fact.  The water needs to contain salts to be conductive.

We will get rain eventually that is a fact.

Edited August 5, 2019 by Gina