Gina

Been looking for INDI drivers suited to ROR automation but concluded that I would rather develop my own (maybe from a more general driver) than just take someone else's code. I have proper H bridge DC motor drivers that I plan to use rather than relays. There's two drivers on an Arduino shield but whether I shall use an Arduino Uno for control I haven't decided - I may drive the shield directly from a Raspberry Pi as it seems overkill to employ two microcomputers for such a simple controller. The shield PCB has the facility for this. Pololu Dual VNH5019 Motor Driver Shield for Arduino

Here's a photo of the SE corner roof retention system roughly fastened in position. This is one possible position, it could go lower if I were to add a block to widen the vertical frame member and move it away from the corner a couple of inches.

A couple of photos, camera casing and RPi roughly where it will go and printing the top outer casing. Printing in cheap PLA, low resolution, for prototype.

I have confirmed that I can hold the roof from lifting off with strong locking pin and hole systems on the four corners connected to the main corner posts to the east and the main middle frame to the west of the roof. These I expect to be at least as strong as the current over-centre latches I'm using at the moment. The only thing to sort out now is the method of locking the roof in the closed position. The solenoid door latch I've bought has very little pull force and is easily stopped by the slightest force against the latch. As mentioned above, I could use a lever to reduce the force on the latch but I'm wondering if it would be better to over-engineer the job and buy a screw type linear actuator such as this one :- Linear Actuator Motor 750N 12V DC 165LBS 50 100 200 400mm Electric Door Opener Under £20 for the smallest one with 50mm stroke. It strikes me that this is a small price considering what it is protecting. This wouldn't care if there was a gale trying to open the roof, it would still disengage. (Not that I would want to open the roof in a gale but a previous strong wind from the east could have pushed the roof hard up against the stop.)

Yes. No problem as the error is tiny and easily compensated by the firmware. In other printers I have had a slope of 5mm across 200mm and the firmware still coped fine.

Oh yes, excellent book.

Another.

This is a bit better.

Had a thought, rather than redesign base and camera casing top I reckon I could simply mirror image everything in the slicer and print what I've got. Present prints are only test prototypes anyway - I shall print more accurately when I have the final design and everything fits together properly.

Hmm... well. I've just tried the new right angled plug USB lead and found the B plug is the opposite hand from the one I designed for! Back to the drawing board - CAD software. At least the A plug is right for the RPi.

Yes, you're right, LH bottom should be green. Z homing should set the start point unless I'm missing something.

The gate hooks and bands have arrived and I've checked that the hooks will clear the middle wall when the roof is opened and they will by at least a millimetre! ?

Parts for securing my observatory roll-off-roof for when I automate it, USB cable with right angle plugs for my all sky camera and large headed clout nails for repairing the roof.

I see you got the Australian version ? Not to worry they work either way up ?

No testing tonight even if it is clear. All design work which I think is almost done.

Matching bottom part of the casing. This is screwed to the passive cooler with M3 screws and to the top part with M5 screws from underneath.

Model of the top part of the outer casing.

If I solder the RPi power input wires directly to the board I can save 10mm height allowing for a slope on the top otherwise the top would be flat which I don't like. I'm changing the arrangement and having the top go right down to the level of the inside of the bottom part. That will make clamping top to bottom easier and put the seal lower down so that if there was a leak it would be below the camera. Not that I intend there to be any possibility of a leak!

oops - forgot to allow for the RPi. OK new design needed... No problem.

The basic top part of the casing, connecting dome to bottom part. The dome can be attached with a ring on top of its lip screwed to the top ring of the casing, with a seal between.

This solves the problem of holding the camera casing together but not attaching the top of the outer casing. The top needs clamping and sealing arrangements for the dome and for attaching to the bottom part.

New designs for basing bottom and camera casing top, the latter underside view.

Decided. Going to put RPi with its HAT and the buck converter in the ASC casing. Just need to increase the size a bit.

Good thought ? Though not the warm room as that gets covered by the ROR but I am planning to mount it on the north side of the ROR. The dome has to be above the roof to get a view of the sky to the south. I could shade a lot of the casing though. Last time it was mounted on the south side in the full sun. Maybe it won't get too hot.

If it weren't for the enclosure getting hot in the daytime in summer I could go back to having the Raspberry Pi and the other electronics inside the ASC casing rather than in a separate box in the observatory. Two advantages - it would save having to seal lots of wires, with just power connections remaining and also output heat to warm the dome and with the inside being dried it's only the outside of the dome that can suffer from dew.