All Sky Camera build - with RPi - Power supply suggestions or advice

[teoria_del_big_bang]

Whilst this prolonged period of endless cloud is upon us I am trying to get this build on the way as I have been thinking about it for some time. I know there is lots of info about in this forum and other sites and have done a fair bit of studying but as many SGL members have made some fantastic cameras thought I would just seek any advance or warnings what not to do and what I should do first before buying anything.

I do not intend anything to be revolutionary so will follow what seems most have done before but want to start off considering most issues people have already encountered and try to get a working model without building it and then changing everything, or at least attempt this although that may not be the end result as so often happens.

• ZWO ASI224 camera - I have one of these and would like to use as I think it should suffice but always open to suggestions.
• I originally thought to use the supplied lens but believe it is far from ideal. I was looking at something like this but finding it difficult to source in UK. 155mm_All_Sky_Camera_lens   OR   Arecont_Vision_mpl1_55_1_55Mm_1_2_F2_0_Fixed
• 100 mm Perspex dome from an auction site with 20mm flange.
• I am designing a 3D printed enclosure that I can adequately seal with o rings in grooves. But I have never tried to print anything waterproof and not certain whether 3D printing can be entirely waterproof. I assume so long as the filament is hot enough and fuses to the layer below it should work. Anyone any thoughts on this. I guess I should print a scaled down version and test it by submerging it.
• As I have no firm plans yet should I be looking at some form of motorised focus mechanism. I wasn't thinking anything automatic but more of something I can adjust manually without removing the dome, so just a motor and belt of some description.
• Control. Not sure but would like to use AllSkEye unless somebody recommends something better. But I am still not sure how to run this remotely. Do I connect camera to a Rpi and run this software in the Rpi or do I need some form of mini computer running Windows, maybe connecting to a Rpi via WiFi or Ethernet?
• Dew control - It seems the cheap and effective method is a few resistors or one of these Dew_Heater_Module_All_Sky_Camera but do I just permanently have these on 12V, I see some designs use some form of temperature sensors to switch them in and out is this necessary? Also some designs use fans for dew control how does this work and is it a case of using a fan or using a heater of some description or is both better?
• I would rather either print of buy an enclosure big enough to be future proof so apart from the camera, maybe a focussing motor and driver, Rpi possibly and then the wiring, is there anything else I should consider leaving room for ?

I am sure when I start to actually build it I will have other questions to answer and will need to ask or research further but this is a start.

Steve

Edited February 14, 2020 by teoria_del_big_bang

[pete_l]

One big question is what do you intend to do with this?.

Is it to perform a simple task such as checking whether the sky is cloudy or clear. Or do you want to do more advanced work, such as meteor detection.

A clear/cloudy sensor doesn't need to be any more complex than a webcam and a cheap fixed-focus fisheye. You aren't aiming for "photo" quality images - just looking to see if there are (any) stars. Their colour, position or pin-pointedness is not important. The window the camera looks through doesn't need to be anything special, either.
For the next step up, which is to identify constellations and produce movies of movement through the night you will need a better lens and an improved cover for the camera. If you are intending to mount it high-up a method of keeping that cover clean - free from dust deposited by rain. However, if your location is surrounded by trees and houses, it is unlikely that a lens providing a horizon-horizon view is needed. Remember, you can point the camera at an angle, away from close buildings.

Much the same applies to meteor detection. Although since they are fast-moving, long exposures aren't needed but a sensitive camera is. As is a low F-number lens.

 

In general, remember that an enclosure that starts off waterproof may not continue to be after repeated cycles of sun and frost/snow. Or if the unit provides a convenient perch for birds, accumulations of dust may be the least of your worries.

Edited February 14, 2020 by pete_l

[Gina]

I was about to ask the same questions.  I have considerable experience of all sky cameras, mostly high performance ones.  I always want the best possible astro images as you no doubt already know.  OTOH watching out for incoming clouds is an important aspect.

[vernmid]

I built one of these. Raspberry Pi powered fun!

https://www.instructables.com/id/Wireless-All-Sky-Camera/

Definitely need to add dew control 

[teoria_del_big_bang]

50 minutes ago, pete_l said:

One big question is what do you intend to do with this?.

Is it to perform a simple task such as checking whether the sky is cloudy or clear. Or do you want to do more advanced work, such as meteor detection.

And that is a very good question. I think initially it is just a project for something to do. But after saying that I want to make something that works and is worthwhile. Cloud detection is one aspect I think would be useful but if I think meteor detection is something I would be more interested in doing.

 

52 minutes ago, pete_l said:

For the next step up, which is to identify constellations and produce movies of movement through the night you will need a better lens and an improved cover for the camera. If you are intending to mount it high-up a method of keeping that cover clean - free from dust deposited by rain. However, if your location is surrounded by trees and houses, it is unlikely that a lens providing a horizon-horizon view is needed. Remember, you can point the camera at an angle, away from close buildings.

So a better lens the the one I suggested above   Arecont_Vision_mpl1_55_1_55Mm_1_2_F2_0_Fixed ?

With regards a better cover is that along the lines of a more scratch resistant glass cover rather than perspex or something much more sophisticated ?

This is for my garden, which is a pretty large garden with no houses behind ours but with some pretty tall trees about so it would not require a full 180 degree fish eye.

59 minutes ago, pete_l said:

In general, remember that an enclosure that starts off waterproof may not continue to be after repeated cycles of sun and frost/snow. Or if the unit provides a convenient perch for birds, accumulations of dust may be the least of your worries.

Good point, I did wonder how people do clean the outside of the cover and assumed it was a very manual process being careful not to scratch the surface and maybe to replace the cover annually.

49 minutes ago, Gina said:

I was about to ask the same questions.  I have considerable experience of all sky cameras, mostly high performance ones.  I always want the best possible astro images as you no doubt already know.  OTOH watching out for incoming clouds is an important aspect.

Of course I know your experience with these cameras and also your ability to get the best out of your equipment Gina and so would be really grateful for any uture advice you can give me 🙂 

19 minutes ago, vernmid said:

I built one of these. Raspberry Pi powered fun!

https://www.instructables.com/id/Wireless-All-Sky-Camera/

Definitely need to add dew control 

I have had a look at this thread already but not yet fully so thanks I will study it a bit more. Dew control yes you are right will be needed I just wondered why some people also use a small fan and whether the heater and fan together work best.

 

Thanks for all the replies so far

Steve

[teoria_del_big_bang]

I am slowly getting on with this build. I have what most  of what I think I need just need to get my final version of the enclosure designed before I print it.

I have a ASI224C camera, RPi 2B and a hard drive to store the pics until I download them.

One thing I am hung up on is the power supply for the RPI. Currently I am using an old RPi 2B I had in a drawer, I may change this to a 3 or 4 later if I need to.

I will probably position the camera some distance from the house but not too far from a 240V source.

However I do not want to really just leave a £5 to £10 5v PS plugged into this power source in all weathers.

So the other option is to build a 5V supply inside the enclosure and supply 240V to it, or I could put a 12V to 5V converter in the enclosure and probably run 12V okay to it as it will not be that far from the house (or use a 12V pond transformer meant for outdoor use). I thought 12V would stand a bit of voltage drop over the length of cable rather than a direct 5V supply).

I just wondered how others power their cameras left outside on a permanent basis?

Steve

Edited March 3, 2020 by teoria_del_big_bang

[Gina]

Mine is attached to the side of my observatory and uses the main 13.8v supply which is inside.  Voltage is dropped to 5v with a buck converter in the ASC enclosure.  Unfortunately that's not much help to you though.  I do suggest keeping mains voltage in the dry and running (say) 12v to your ASC.

[JamesF]

I have an RPi in my Stevenson screen which is on the north east wall of my observatory and supplied from a 12V source inside.  I was also wondering how to power it when I came across a socket intended to replace the cigarette lighter on a car that has two USB charging sockets as outputs and takes a 12V input, so I used one of those and plugged the RPi in using a USB lead.

I thought I had a better photo, but you can see it on the left here:

James

[JamesF]

Aha.  Didn't look hard enough:

[teoria_del_big_bang]

7 hours ago, Gina said:

Mine is attached to the side of my observatory and uses the main 13.8v supply which is inside.  Voltage is dropped to 5v with a buck converter in the ASC enclosure.  Unfortunately that's not much help to you though.  I do suggest keeping mains voltage in the dry and running (say) 12v to your ASC.

Yes I liked the 12V option above all others as well.  I think a 5V supply would lose too much in the wire resistance and 240V has a habit of getting its own back from time to time.

Steve