Power and control box build

[Wyvern]

After many nights struggling with USB issues and dealing with a tangle of power cables I decided to build this!

Dremel or multitool
Hot glue gun (or hot glue sticks and a lighter)
Drill + various bits

Parts
Old PC PSU
2x 5A Buck-Boost regulators
MyfocuserProV2
Flight case
5.5mm Plugs (ebay)
Mini PC
Relay board

Flight case modification
There will need to be a few holes cut and drilled in your shiny new flight case, but don'y be fooled by that shiny metallic appearance... it's fibreboard with a foil laminate.
So first to fit the PSU
I traced around the fan and screw holes on the PSU on a sheet of paper, placed it where the psu would sit and start drilling and cutting.

Modifying an old PC PSU for use as a power supply
Suffice to say that modifying your PSU will invalidate your warranty and whilst all mods are being performed on the low voltage DC side there is always a risk when using mains voltage appliances. With that being said... off we go!
So first of all you will find that your PSU will not turn on, the key to this is the green wire (PS-ON)
What I usually do is cut the green wire and the ground wire next to it ( it can be any ground wire) These can then be wired to a switch or relay.

Now, all the yellow wires coming from the PSU are 12v and can be used to power your mount, camera etc. The red wires are 5v and can be used to power any usb devices etc. All the black wires are ground.
Now, the power rails in a PSU are super stable however I like to put another layer of protection in the form of buck-boost regulators between the PSU and the camera and mount.

This is the one I used and can be bought from china for very little. The only problem with this model is that you cannot actually boost the voltage...but it works as overcurrent protection. I clipped off the 4-pin molex power connectors and connected the 12v yellow cable and a ground to the VIN.

Adding the 5.5mm jacks.
This wasn't rocket science, I drilled holes and fitted the plugs. I then decided which ones were going to be my mount and camera plugs and soldered the wires from the VOUT of the buck-boost units Positive to the centre pin and ground to the outer.


The Autofocus module
Please refer to this post on how to create the autofocuser.
https://www.backyardastro.org/forum/diy-astronomy/whats-that-you-want-aurofocus-but-dont-want-to-spend-a-fortune/
I have mounted it with hot glue to a separator board which came with the flight case, the output to the stepper motor is via a RS232 connector hot glued through a hole in the lid.
The Arduino is powered via USB from the mini PC which I will cover below.

The mini PC
The mini pc was not in my original design for this setup but there's really nothing special, my only requirements were a minimum of 5 USB ports 2 of which had to be USB 3.0 for the guide and main camera. And be able to run SGpro and phd2 without a problem.
The case should be cut out so the ports are accessible from the outside. Unfortunately it needs a separate power supply as the voltage does not match the PSU :(

Yes, its hot glued!

Bringing everything together.
The last piece of the puzzle is the USB relay controller This turns on the PSU which allows power to flow to all the components.
I used https://www.tinyosshop.com/index.php?route=product/product&product_id=340 but you don't need a 4 port for this application I just had it left over from a different project.
I hooked up the green and black wires to one of the relays and hey presto.

I used powershell code to control the relay
$port= new-Object System.IO.Ports.SerialPort COM7,9600,None,8,one
$port.open()
$port.WriteLine("n")
$port.close()
Use "n" in the third line for ON and "d" for OFF

I think I have covered just about everything, any questions? post below!