Gina

Bit cooler today and my brain has started ticking over!... The wind vane can have an optical Gray code encoder with 3 bits which I can easily design and 3D print. The anemometer can be as it already is with 3 tiny magnets on the rotating bit and a Hall switch. Low wind speeds can be measured by timing the interval between pulses and higher speeds by counting pulses. This means 4 bits of data can carry the wind data. This could be transmitted to the base station indoors where all the data would be processed. Something like an RPi would seem to be overkill - I just need some form of transmission that can handle 4 bits of data at a relatively low speed. OTOH it could be that the RPi is the simplest solution. I know relatively little about modern short range comms but I'm sure there must be something that can handle this. My old Maplins WS use a radio transmitter at (I think) 433MHz and ran the transmitter station from a pair of AA batteries. I don't need to use such low power as there will be mains available. Bluetooth comes to mind but I have not had much joy with Bluetooth in the past and I'm not sure it would have enough range and the ability to work through reinforced concrete walls. I know a bit more about WiFi and I do know that it has the range.

I think I may have a plan for finding where I can put the wind sensors where they won't interfere with astro imaging. If I take the imaging rig off the mount and replace it with the DSLR set to wide angle I can take a panorama. There are trees that already block the FoV from the mount such as to the north where there's a shed I could mount a high pole on but not as high as the trees as seen from the mount.

When it gets cooler and my brain starts working again I shall be sorting out the sensors, in particular the wind direction, though the main problem is where to put the wind sensors without interfering with my astro imaging.

II thought you might be using all RPi and not Arduino @RadekK being well versed in INDI. Those Weather Meters are the same as I used many years ago. They didn't last very well in the storms we get at times.

Interesting clouds.

Camera temperature has dropped to 3.3°C now as the clouds roll in.

In fact that's a perfectly adequate operating temperature but I'm glad I have an efficient cooling system - it was worth it in the end. Tap water is nice and cold but no tap in the obsy 🤣. The overflow water from the spring runs quite near the obsy and that is cold so I could pump that in but we don't get that many hot days in the year so not worth the trouble!!

With the high ambient temperature and strong sunshine I have the camera cooling on FULL and the sensor temperature is still 4.6°C. Of course I can only cool the water to around 30°C or so - a little above ambient and it may well be above 30°C in the observatory. Getting over 25°C delta T isn't bad for a single stage Peltier TEC cooling system.

Earlier designs have used optical encoder discs and photo detectors. Hall sensors are less precise as are reed switches. I'm thinking of going back to optical sensing with Gray coding.

I plan to collect the following data :- Wind direction Wind speed Temperature Humidity Atmospheric pressure Rainfall I may combine outdoor measurements with inside the observatory. I can mount a Stevenson Screen on the north wall of the observatory to contain sensors for ambient temperature and humidity. These sensors and transmitter can be powered from the observatory. Atmospheric pressure can be measured indoors. That leaves the wind and rainfall measurements.

I wasn't originally thinking of using low power systems as power is available at various locations around the property in sheds and similar. Power supply to the electronics could be protected in conduit.

Thinking "out of the box" maybe the way to go is to have very simple transmitter units and collect the data indoors. Hence I have changed the title of the topic. Many years ago I used the Maplin weather station with my own modifications to overcome some of the problems. In fact I got through two sets as they didn't last very long. That used a 433MHz RF transmitter as I recall. I thought of using the RPi as I have plenty of experience of using these with my astro projects and KStars/Ekos/INDI software. Modifying the C++ code to expand INDI drivers to cater for specialised features is no problem to me. The Arduino code is similar but the Arduino doesn't have WiFi.

No it doesn't. 8 or at most 16 angle slots would be fine.

I have a design for an Arduino based weather station but the problem is communicating the data indoors. Previously I have used a cable connection but have the cables eaten by rats. The ideal solution would be WiFi and from my experience with astro imaging, the Raspberry Pi would seem to be a much better solution than Arduino. There are a couple of things that rely on Arduino libraries which will need either libraries for the RPi of a rethink. These include 1-wire which I think may be supported but also the Arduino design uses the Melexis MLX90316 rotary encoder chip for the wind vane with Arduino code and don't know if there's RPi code for it. OTOH I'm not entirely happy with this chip and considering other ways of measuring the wind vane angle.

Magnificent Dave. Great stuff!!

The sensor temperature has now reached 22.5°C in the warm sunshine with the cooling on LOW so a bit more cooling would seem sensible.

Wonderful - well done - superb job.

I think the LOW cooling level could be increased as the sensor temperature now is 12.6°C rather than adding another buck converter and power MOSFET etc. to control it. The LOW cooling voltage is supplied from its own buck converter, separate from the 5v supply for the RPi, so I only have to turn up the output voltage.

The above showed a sensor temperature of 3.5°C. With full cooling it's reached -13.5°C and still going down. This is the image. Still showing some hot pixels.

ASC seems to be working well. This is with minimal cooling (5v) and it wants a bit more but not really the full 13.8v. Think I may provide an intermediate setting.

Thank you. Unless we get a bad earthquake the focus should stay put now. Water resistance remains to be seen.

PHEW!!! Seems fine! WOW!! That bunch of white specs just above half way up is the dome damage shining in the sunlight.

All set up outside, power on and ready to test! Oh dear, here we go again. If the focus is out I think I shall cry!!!

Yes, 10m above ground is the standard. I had mine on a mast 6.8m high but it had to go because it interfered with my astro imaging. Planning regs limit the height and it has to be self supporting.

I've been at this stage before and the feeling of déjà vu is overpowering!!