Gina

Back to the chain drive for the roof. Designed and printed the bracket to attach the west end of the chain to the roll-off-roof.

I think I have a design for opening the window when the roof is opened using 6mm diameter braided cord and a couple of pulleys. This can be disconnected if I want to open the window without opening the roof. This dispenses with the traditional wooden lever system so the guttering downpipe will not be in the way. I can stiffen the window frame using wooden blocks screwed to the corner joints. This diagram shows the roof and window open. As the roof closes the cord and pulley system pulls the middle of the diagonal cord upwards and the geometry is arranged such that when the roof is closed the window is pulled up to the vertical position and closed. The reverse happens on opening the roof. The window will have a weight on a bracket to make it open. This geometry also means that the stronger pull needed to start closing the window is compensated by pulling on the middle of the diagonal providing extra leverage.

Ah yes - Heath-Robinson - my hero 😄

New arrangement.

I think this idea is a goer.

Too hot for me too!

Going back a while I had an idea using the rope to pull the window closed. This is very complicated but could probably be simplified. To free the window so that it could be opened with the roof closed, the rope could be disconnected somewhere.

Might be possible. Another idea to think about. Thank you.

The motor drive for the roof is proceeding but meanwhile I have been giving more thought to the fold-down east window. How I know the consensus of opinion on this sort of thing is to have the end flap mechanically connected to the main roof so that opening the roof opens the flap and vice versa. However, with the two currently independent and both manually operated, I find I often like to have the window/flap open with the roof closed. I have also found that having the window pivoted along the bottom has not worked as well as expected. One problem is that the window frame is not very stiff. Also, I have had to put the downpipe for the ROR guttering back to the south side and would be in the way of a traditional mechanical connection between roof and flap. All this has led me to thinking again about the best way of opening and closing the window. I think the main point is that I don't really want the window and roof operating together (although I never have the roof open and the window closed) so a mechanical coupling between the two is rejected. There is no particular reason not to have two motors and controls (other than a bit more cost, though I do have other motors and the motor driver board can control two DC motors). The next question is how the window opens. Currently there is no feasible way to open the window remotely as it is bolted to the roof to hold it closed and even with the bolts undone the weather strip stops the window opening without a good push. Opening the roof does free the weather strip but the window stays in the closed position without some sort of balancing weight to open it. The latter is a possibility. Another thought is a sash style opening window but this has other problems.

The motor drive for the roof is proceeding but meanwhile I have been giving more thought to the fold-down east window. How I know the consensus of opinion on this sort of thing is to have the end flap mechanically connected to the main roof so that opening the roof opens the flap and vice versa. However, with the two currently independent and both manually operated, I find I often like to have the window/flap open with the roof closed. I have also found that having the window pivoted along the bottom has not worked as well as expected. One problem is that the window frame is not very stiff. Also, I have had to put the downpipe for the ROR guttering back to the south side and would be in the way of a traditional mechanical connection between roof and flap. All this has led me to thinking again about the best way of opening and closing the window.

Ha ha ha!! Just looked outside - it's getting murky. Not thick yet but it's in the air and there's a hell of a dew. Up above the clouds have cleared and there are some stars out plus Jupiter shining brightly. The local news forecast fog tonight and tomorrow morning. Seems about right for once!

Yes indeed, feels very "close" here too, Electrical storms are not supposed to arrive until tomorrow evening but who knows! I shall not be risking imaging tonight even if the sky does clear - I haven't got my automatic roof closing done yet. I have the parts but everything takes a lot of time and energy these days.

Good luck, Neil.

Visibility is alright though not great maybe 10 miles but hazy in the distance. Solid light grey cloud can barely make out some shapes.

CO says it's clear tonight but also says just 11% cloud cover ATM and there's total cloud cover!!! I think if the sky clears for imaging tonight it will be a minor miracle!

Managed to move the hands nearer the clockface and hence the tiny magnets in the ends nearer the Hall sensors and get the clock working but I think there is a future project here to fix the problem properly to provide more reliability.

I've come here because after several years of perfect operation and timekeeping this clock has developed a fault following a power cut during the night a few days ago. The Hall sensor that detects the position of the minute hand has become unreliable. After a power cut or operation of the GMT/BST switch, the clock is run very fast until the hour hand is detected just before the 12 o'clock position with the minute hand at about ten to the hour. At this point the clock slows down allowing time for the minutes Hall sensor to detect the minute hand at the 12 o'clock position. The 12 o'clock position having been found the amount of rotation required to get to the right time is calculated from the time given by the Real Time Clock module. The clock is driven fast until the calculated position is reached and then run at normal rate. The result is that the clock shows the correct time to within a few seconds. I now need to find out why the minutes Hall sensor is not detecting the minute hand or possibly using another method of detecting when the minute hand is at exactly 12 o'clock.

Imaging will be easier when I have my ROR remote controlled.

There is no need to run the motor at other than full speed - it isn't that fast - 18v motor running from 13.8v. I don't think acceleration or deceleration are needed either but I'll confirm that when I have the system running with endstop switches. These will be the old Z probes for my 3D printers (been replaced with piezo sensors). They're waterproof, easily mounted and sense any metal at around 4mm. No moving parts (other than the roof) or electrical contacts. They work very well with Arduinos etc. 6-36v supply with NPN open-collector transistor output. I shall want a couple of push-buttons for local control so that I can use the motor to open or close the roof when in the observatory. I shall also want to mount the rain sensor in a suitable place and connect it to close the roof if it rains.

On to the motor drive, I released the clutch on the motor to free the chain, pulled the chain through and connected it temporarily to the east end of the roof with a clamp. The weight of the chain was enough to pull the roof open. Decided to see if freeing the chain from the worm gear motor drive would allow my to close the roof by hand in the event of motor failure (the reason for choosing this special type of garage roof opener motor unit). I opened the roof about half-way, pulled the chain through to take up the slack and then (with the clutch free) pushed the roof closed with the chain going through the motor unit. Found I could do this quite easily. RESULT! Next I tried power on the motor to see how well it opens the roof. Connected motor to bench PSU set to 13.8v and applied power and (once connected the right way round) the motor opened the roof effortlessly! Maximum current was about 2A and generally around just 1.4A. Test successful!

Yes, same here.

According to the weather forecast it might be possible tonight but I've probably done enough for today - have to be so careful ATM not to overdo it.

This thread will return to imaging in due course - whenever that is... 🤣

If it's that toxic it may be banned from sending by post.

Wikipedia says something to do with Donald Trump!?