Mini PC placement: cabling, pros, cons

[aleixandrus]

Hi! I'm tryting to get rid of the cable mess I have in my setup  (EQ6-R + Samyang 135mm + ASI183MM + focuser + filter wheel + guiding). I also having problems with my laptop as it turns off due to the low temperature or humidity (I think is the battery). So, I've got a PegasusAstro Powerbox Micro and a Mini PC (the Eagle solution is just too expensive and I like NINA so ASIAIR is not my first option). However, I think this route will simplify the cabling but now I'm trying to put everything together, it is not that easy. I see this routes:

1. Put the Mini PC and Powerbox on the OTA, cable the mount (power+data) to the OTA and cable the OTA (power) to the ground.

2. Put the Powerbox and a USB hub on the OTA, cable the mount (power+data) to the OTA and cable the OTA (power+data) to the ground.

3. Same as 1) or 2) but cabling the mount to the ground instead to the OTA.

I know it may be a personal preference and depends on the particular equipment. For instance, my OTA is quite small and I struggle to fit everyting over it. I also read a lot of topics in this forum and saw many (many) pics of complete setups and no consensus is reached. I'm trying to decide ASAP as I'm in time to return the Mini PC and the Powerbox Micro and get the Powerbox Advance, which includes a USB hub. Removing the Mini PC from the OTA will allow me use a larger/powerfull/cheaper one despite I may not need it to run NINA. All equipment will run from the backyard, I'm not going to a dark site, no battery needed.

I really appreciate any commets or hints as I'm sure most of you have/are having this issue. I'm also wondering when the manufacters will start using mounts with cabling inside by default and USB Power Delivery to remove most of the cabling!

PS: Please, feel free to move this topic to another forum for better fit

[teoria_del_big_bang]

There is of course more than one way to do this as you suggest and I had the same dilemma a while back.

In the end I actually placed the fanless PC on the tripod not  the OTA and bought a Pegasus powerbox advanced (not cheap but you would not regret getting one especially with NINA as it can control everything on it from a remote PC). The PPBA was placed on the OTA.

Reasons I decided on this after a lot of thought:

• Keep the weight added to the OTA to a minimum as the PPBA weight very little.
• Using this setup I could use short good quality USB cables to connect everything  (except the mount - see below) to the PPBA and also power everything (except the mount - see below) from the PPBA .
• Wherever you place the PC there will always be the at least 2 cables that need a loop to allow movement., but my decision was based on the fact I could get away with only 2 looped cables that need to move with the OTA and it kept the weight on the OTA down (my PC whilst fanless has quite a heavy heatsink type casing).

1. If PC and PPBA on OTA need  3 looped cables (maybe 4 if PC is 5V or 19V and not 12V):
   • 1 USB from PPBA to mount
   • 1 power either from ground to mount or PPBA to mount
   • 1 power to PPBA 
   • 1 power to PC IF PC is not 12V and so cannot be powered from PPBA.
      
2. If PC on tripod or fixed portion of mount needs only 2 looped cables,  as the power to PC and both the power and USB to the mount do not have to move if you run the power from the power source on the ground and run the USB direct to the PC and not the PPBA, so can be neatly clipped up if necessary without needing to worry about them being stretched or getting trapped when the mount slews. :
   • 1 USB from PC to PPBA.
   • 1 power from ground to PPBA.

Steve

Edited January 15, 2023 by teoria_del_big_bang

[aleixandrus]

Thank you so much for this very detailed reply!

My mini PC is about ~11x11x4cm, ~280g and 12V. My initial plan is to tie all cables to a fixed point in the mount (EQ6R Pro) head: mount USB to PC + mount power from powerbox + main power from ground to powerbox. I can attach them to each other using one of those flexible cable conduits. This way, I skip the USB hub (the PC has enough ports), the powerbox handles everything (so I only need one power supply), I reduce cable weight on the connectors (using that fixed point) and I can disassembly the whole OTA in one piece except for 3 connections. I know I may have problems mixing data and power or even overpowering the Mini PC USB controller but I think it worth a try.

However, I'm not sure if this reasoning has any flaw, that's why I started this thread. The mount to head cable loop causes me some issues and it seems easier to just let those cables go to the ground, as you say. However, I still having a loop from the PPBA to the ground and I have to add USB hub and power supply so I still don't see a clear advantage...

[Flamidey]

Here's my setup with a Beelink GTR 5, if it helps with the cable management.
Setting up everything requires 4 connections: Mount DC, Mount USB, PC DC, Camera DC. All the rest is permanent as I can move the OTA+imaging+PC all at once.

 

[jpoulette]

On 17/01/2023 at 07:40, Flamidey said:

Here's my setup with a Beelink GTR 5, if it helps with the cable management.
Setting up everything requires 4 connections: Mount DC, Mount USB, PC DC, Camera DC. All the rest is permanent as I can move the OTA+imaging+PC all at once.

Very nice cable management set-up.

I'm just putting together my first imaging WiFi set-up with a smaller refractor and I am a little concerned about it looking like a pile of spaghetti.

The photographs in these forums are really giving me some good ideas - thank you for posting yours.

Jim

[aleixandrus]

Same here! Thanks for the pics, I think I get some useful ideas I'll try to put into practice soon. Hopefully I'll edit this post with some photos

[ONIKKINEN]

My mini-PC sits on a quick couple wallmount ziptied to the tripod spreader of my AZ-EQ6.

Best image of it i could find:

Its not too bad in terms of cable drag, but since i have no powerbox it means one DC cable for the camera goes all the way to the battery on the ground. One USB3 from the mini-PC to the camera, and one short cable from the camera to the guider sitting in am OAG.

This is a very convenient and easy way to mount it, but maybe not the most elegant.

Benefits of this method would be less strain on the mount as its not on the scope, and maybe less thermal effect since its far away from the scope. I want to keep scopeside waste heat to a minimum as with a newtonian there may be tube currents that ruin sharpness otherwise. And its easy to do, so if youre lazy its a 1 minute job to ziptie a wall mount to the spreader.

[CCD-Freak]

I am a bit of a "Black Sheep" since I prefer to put the mini PC and such on the pier or tripod instead of mounting it all up top on the optical tube.  I do it to reduce cable clutter, weight and wind load and it is also easier to protect the electronics from dew, frost or low temperatures.   By using the internal hub on the camera I can reduce the number of cables which I run through "cable braid" that is secured at each end to take the strain off the connectors.  Cable braid allows each cable to move separately which makes the bundle more flexible.  

To quote Mando...."This is the Way"  8^P

[aleixandrus]

So nice cable arrangement! I'll probably go that route if I had a permanent pier... I could use a more powerful 'full' PC. My camera also has a USB hub but I need one additional port as I'm adding a filter wheel. My focuser needs a dedicated 12V power input, so more cables. For now, maybe putting everything over the OTA and using a flexible cable conduit tied at both ends to avoid damaging the connectors, as you point out, will hopefully ease (dis)assembly) the whole OTA as it should be "one single package".

Right now I have all pieces (except a 2.1mm>2.5mm short power cable for the Mini PC I forget buying, shame on me). I'll investigate how I can attach the PC and the powerbox together and post some pics of the result

[CCD-Freak]

The HP mini PC has 4 more USB3 ports on the back side for a total of 6 as well a USB C  connector.  By utilizing the hub built into the camera to control the EAF focuser and the EFW filter wheel I can keep the cable count down.

 

[jfrijhoff]

On 19/01/2023 at 18:52, CCD-Freak said:

I am a bit of a "Black Sheep" since I prefer to put the mini PC and such on the pier or tripod instead of mounting it all up top on the optical tube.  I do it to reduce cable clutter, weight and wind load and it is also easier to protect the electronics from dew, frost or low temperatures.   By using the internal hub on the camera I can reduce the number of cables which I run through "cable braid" that is secured at each end to take the strain off the connectors.  Cable braid allows each cable to move separately which makes the bundle more flexible.  

To quote Mando...."This is the Way"  8^P

 

 

That's a sweet looking rig! Do the mini-PCs hold up well in general in (freezing) cold and high humidity?

[ONIKKINEN]

My mini-PC has worked throughout anywhere between +10c and -25c and 80>99% humidity without much in the way of issues.

The waste heat generated by the PC is enough to keep it free of frost and dew when in operation, even at the 99% humidity mark.

[CCD-Freak]

9 hours ago, jfrijhoff said:

That's a sweet looking rig! Do the mini-PCs hold up well in general in (freezing) cold and high humidity?

I have used the my mini PC during the hot summer months in Texas and in cold weather down to about 30F so far with no problems.  When I get out in even colder weather I will be putting the PC in a plastic container which hold in the small amount of heat the PC generates which also keeps dew at bay.  My SRO dark site is usually quite dry so dew is usually not a major problem. 

[jfrijhoff]

Thanks both! I’ll keep in getting familiar with NINA using my old laptop, and then a mini-pc is looking very attractive afterwards.

[jfrijhoff]

Got a great deal on a virtually new MeLe quieter3Q. Looking forward to using it when it arrives! Cuiv also recently posted a video on setting up a mini-pc on his YouTube channel, found it very helpful.

[dk101]

my setup is quite similar to @teoria_del_big_bang's above. I also have a mini pc strapped to one of the (azeq6) tripod legs with two cables up to the scope (data and power) on which i have Pegasus PBA which deals with everything else. Mount power and data are separate. Also, as @teoria_del_big_bang said, good USB cables are a must. Lindy Anthra ones work for me (and they have them in short lengths) and i would recommend them. Before i had these, i would occasionally get data dropouts etc which were annoying.

Like the others said, minipc creates enough heat to keep frost/dew off. i had mine out on the both clear nights we had here in london this winter (...) and while the scope ended up completely covered in frost, the PC was happily dry. I did keep the nevada power supply in a dry box, away from dew, which is highly recommended and conducive to longer life.

I run NINA on the pc and remote-desktop to it from either another PC or my iPad from the house and it all works like a charm and having the PC on the tripod leg instead of on the OTA has never been a problem.

[teoria_del_big_bang]

4 hours ago, dk101 said:

good USB cables are a must. Lindy Anthra ones work for me (and they have them in short lengths) and i would recommend them. Before i had these, i would occasionally get data dropouts etc which were annoying.

Exactly the same in my early experience and also use the Lindy Anthra cables whereever I can, I especialy love the short 0.5 ones when they are enough to reach the Pegasus, keeps everything neat and also better for any signals.

Steve

Edited May 13, 2023 by teoria_del_big_bang

[CCD-Freak]

Here is a picture from last month showing the new GEM45 C8 setup on the Todmorden pier I built last year.