Gina

Aluminium wind vane added.

Side view of wind vane unit (or part of it) showing the vane holder, axle and ball bearing fitted into the aluminium disc. The encoder disc can be attached to the axle above the aluminium disc inside a 3D printed casing.

This would be the new wind vane print with slot to take the vane and cavity to take the magnet. Top view. The encoder rings could be added on top of the centre circle. Or alternatively the encoder unit could go above the aluminium disc. I shall probably use threaded rod as the axle.

Hmm... The cylindrical magnets (15mm diameter and 7mm thick with countersunk hole) I was hoping to use don't seem to produce much drag but a bar shaped one (42mm x 9mm x 7mm) produces quite a lot. This is a bit less easy to mount but It could be held with a suitably shaped 3D printed housing. The main point though is that it's heavier and probably too much to balance the plastic wind vane. I could make the vane itself out of thin aluminium though which would be heavier than the thicker plastic. I have plenty of thin aluminium sheet. Some experimenting needed

New wind vane design.

Been for a walk up the hill and been thinking... Since the wind vane is not going on the top of a mast the bearing(s) can be much smaller and therefore produce less drag so the whole thing could be smaller - more like the commercial units. Instead of the large saucepan lid I could use a simple aluminium disc (which I think I already have) and the magnet could be smaller and lighter and still produce enough damping force. I have a number of the rare earth magnets of various sizes. The whole vane assembly could probably be one (or maybe two) 3D printed parts.

I have an aluminium pipe about 2" diameter or a bit smaller and 5m long. That's a good start, already twice the height of the observatory. My original wind instruments are on a pole about 6m high consisting of an iron water pipe then (I think) 28mm copper plumbing pipe which has bent in the storms. Aluminium is much stiffer and stronger. The Met Office recommended height for wind measurement is 10m but I don't think that's necessary for amateur meteorology. I'm not even sure it needs 6m but I can extend the 5m pipe with some smaller pipe (like I'm using for the ASC) to fit inside. So I think I have the main mast covered. The next thing is the arm to take the weather station stuff. I think that wants to be aluminium too. I have a choice of tube, channel or extrusion left over from making my 3D printers. The extrusion is heavier so I'll probably rule that out. The problem is attaching it to the mast. It needs some kind of strong bracket but attaching to round tube is not so easy. I guess I could use aluminium plates either side bolted through. There is both weight and windage of the weather station parts to consider. I know I do lots with 3D printed plastic but in this case I don't think it would be strong enough.

Think I prefer the first - simpler.

Another :-

One idea :-

This was the original arrangement with wind and light measuring instruments on the top of the mast with the Arduino in the observatory and using "1-wire" to connect to the sensors. All this was before the Raspberry Pi came to my attention (maybe even before it came out). With that and now with at least one of the 1-wire device being discontinued I am having second thoughts. The RPi 3 has Wi-Fi and WLAN communication of the data back to my indoor computer is a definite possibility. I am already doing that with my ASC so why not the weather station too? That means just a power cable going up the mast.

The current design for the wind vane part looks like this but I shall need to alter the mounting to fit it on an arm coming out from the main mast. The top is an aluminium saucepan lid which provides damping for the wind vane in conjunction with a supermagnet attached to the rotating part (grey block on left). The direction is sensed by four slot type optical sensors on the fixed part with an interrupter plate on the rotating part. The current mounting arrangement is to fit on the top of a hollow mast (aluminium tube) so that needs changing to a side mounting.

I've been working on the ASC but feel like a rest from that so now looking at the weather station again. The anemometer is finished as shown in the photo below where it's sitting on my desk lamp/magnifier. A lot of the wind vane part is finished but I shall be changing the design of the mounting. The anemometer will still be mounted on top of the wind vane damping plate.

Hadn't thought of that

Modified 4 28BYJ-48 5v stepper motors for bipolar connection and attached 4way connectors to plug into the focussing board and HAT. Gradually getting there I'm only "running in bottom gear" ATM!

I'm now considering having the wind instruments and my all sky camera on the same mast from an idea by angryowl. Probably have the ASC on the main mast and the wind instruments out on a boom to one side.

Not sure now - I suggest looking at the datasheet.

Connectors arrived today and I've wired up the focus motor drivers board.

No particular hurry, the moon is going to spoil any night sky imaging for the next several days or more even if the clouds stay away.

Waiting for connectors now - maybe they'll arrive tomorrow...

This shows a better layout with connectors.

Stripboards have arrived Bit tight for three driver modules as there are just 24 strips - can be done though.

Here is the new design for the focus motor plate. Larger diameter to accommodate the outer motor mounting holes and larger cut-outs to save filament .

This diagram shows one of the motors, complete with gear and mounting holes moved outwards centred on the other gear.

Unfortunately, turning the motors up the other way is not just a case of mounting them underneath in the same holes because the camera tube gets in the way so the plate needs redesigning and re-printing so that the motors can be moved further out. The diagram below shows the problem the motors need moving outwards. If I keep the same size gears it's simply a matter of pivoting the motors about their axles, or the motor gear can be rotated around the centre of the adjuster screw gear as well.