power distribution box New Power Distribution Box

[Stargazer33]

At long last I am starting my new power distribution box build. My wife is away on holiday with her sister, so I can leave things lying on the dining table whilst I get on with the build!

I decided to make a new distribution box a little while ago as the PSU in the old one (build thread here) failed during a solar imaging session. I had to replace the PSU with a much lower spec one I had lying around just to use my equipment. Also because of the design, I had lots of cables dangling from the power box, which sits on the patio table, across to the mount and scope - not very convenient/safe.

I will be using the fuse holders, switches, LEDs and phono sockets & LED voltage controllers from the old build, but using GX12 aircraft sockets (different pin configurations for different voltages) instead of the old 2.1mm x 5.5mm DC Jack sockets. Main power (13.8V dc from nevada linear PSU) will enter the power box through a Neutrix SpeakON connector.

The box I have chosen is a black ABS box: 220mm x 150mm x 64mm and will sit on the mount using the polar scope cap as a fixing point. The cables will then feed the mount, DSLR, anti-dew heater tapes, focus motors (main and guide) and a StarTech 7 Port USB 2.0 Hub, which will in turn link to the main & guide cameras and back to the laptop.

Each device will be powered through a Voltage Step Down Buck from the supply 13.8V DC except for the mount, which will have the full supply voltage.

As before, I have designed the box layout in CoralDraw 8 as I am running XP and sketchup isn't compatible with such an old OS!

Here is the planned layout:

The RJ11 and RJ45 sockets are for my focus motor hand controller which will be modified also. The power and control will be taken out of the handset and will be moved to the new power box. A Cat 6 network cable will then take the power to the handset and the button signals back to the controller in the power box. This will then link out to the focus motors via an RJ11 lead. To keep things simple I am just using one signal out cable and will swap it between the guide scope and main scope focus motors.

 

Parts List (so far!):

ABS Box: ABS-BLACK-PLASTIC-ELECTRONICS-PROJECT-BOX-ENCLOSURE

Neutrix SpeakON Plug/Socket: Neutrik-NL4FX-4-Pole-Female-Loud-Speaker-Professional-Speakon-Connector                                                                                                                                                                Neutrik-NL4MP-ST-Screw-Type-Male-4-Pole-Speakon-Chassis-Panel-Mount

5A DCDC Voltage Step Down Buck: XL4015-5A-DC-DC-Voltage-Step-Down-Buck-Converter

Aircraft Plug/Socket - (2, 3, 4 & 5 pin variants): GX12-2-2-Pin-Plug-and-Socket-12mm-Screw-Type-Panel-Connector-Aviation

RJ45 Keystone Socket: socket-cat6-utp-keystone-panel

RJ11 Keystone Socket: rj11-rj12-6p6c-panel-mnt-keystone

 

More to follow as I progress - hopefully tomorrow.

[MarsG76]

Cool project... When the cat's away the mouse can play ?

 

[Stargazer33]

Some progress and a realisation!

    

    

      Disassembling old power supply box for parts.  

 

On the dew heater side I've not allowed for the control knobs! The large centre holes in the 5th photo are for the fuse holders; this really needs to be where the control pots are and so these holes should be 6mm in diameter and not 12 as for the fuse holders! The fuse holders will then have to go somewhere else. I probably should buy a new box and start again, but I am going to try to fill the holes with Epoxy and re-drill them. But that's a job for another day.

[Stargazer33]

Not sure why some of the photos are portrait, as they were all taken in landscape! For some reason during the upload process they were rotated 90°!

[Stargazer33]

A little more progress today. I've finished putting all the buck converters in for the power leads & the buck converter for the anti-dew straps. I'm going to fit a single fuse holder for the three dew controllers, but I've still got to decide where to fit it.

A couple of pics:

 

 

 

[fozzybear]

neat and tidy (no robins nest here) By any chance an electrician/electronics engineer?

 nice work so  easy to trace any problem. Excellent project

Andy

[Stargazer33]

Thanks Andy! Yes, electro-mechanical technician for the last 20 or so years! Worked on things as diverse as fax and photocopiers, corrosion monitoring probes for the oil & gas industry, control magnets for the LHC at Cern, to Police Aviation and SAR communication equipment.

[Stargazer33]

Today I managed to rewire my electronic focuser hand controller and move the boards into the new power box.

Hand controller before:

Hand controller after:

 

Focuser buck converter and Arduino nano control board now in new power box:

.    

[Mick J]

Good work, looks really nice - still doing all this on the dining table ?

[Stargazer33]

Yep! Doing it when my wife's out now!?

[Stargazer33]

Managed to spend some time today on the power box. Almost completed apart from the switch for the focus controller which I managed to over tighten and snap in half! I also ran out of LEDs and need one more for the focus controller. I am also now thinking of putting in a main power switch and LED.

I also set all the buck converter voltages (something I should have done before I tied all the wiring in!). From left to right in the second picture they are: 13.8v (no buck) mount; 12v DSLR coolbox; 12v spare; 8.4v DSLR; 5v usb hub. The heater tape buck is also set to 12v.

It's a bit tight in the box and there is some tidying up to do, but I'm quite pleased with it so far.

  

[bottletopburly]

great job bryan ??

[Stargazer33]

I managed to braze the broken switch back together at work and reassembled it before wiring it into the focuser circuit. I also put in the missing LED on the focuser circuit.

Now the bad news. Looking at the wiring again after the test powering up, I've realized that I've wired up all the buck converters so they are permanently live! I've wired the isolation switch on the output side of the buck! This then goes through the fuse to the socket. So not only is the buck permanently live, it is also not protected by the fuse! The only circuit that is wired correctly is the Arduino based focuser circuit.

So I'm going to have to undo most of my wiring and start again! (Please refer to my signature tag line!)

[Stargazer33]

Finished re-wiring the power box tonight. It doesn't look too pretty, but it works! Still a bit of tidying up to do and I need to get another mini toggle switch to isolate the power to the heater tape buck. It's then a case of mounting it on my 'scope and measuring how long I need to cut all of my feed cables; fitting the aircraft plugs to these leads and then waiting for a clear night!

 After removing most of the previous wiring and soldering the power feed wires to the toggle switches.

 After rewiring.

[Dr_Ju_ju]

Nice job...

now if only you'd had a larger box, to drop a single board computer in there, you could have made a complete control system (for imaging?) with full remote control, if wanted....

[Stargazer33]

That might be a project for next year.

Although I only have limited views due North and due South, I think my next project is going to be trying to figure out how I can wangle an obsy! It will probably take a while as on limited funds I will have to buy bits each month! ??

[Stargazer33]

Finally I've managed to finish my new on-mount power distribution hub.

I have had to partially rebuild it after I carelessly plugged the banana plugs of the power lead into the wrong outlets on the PSU and managed to burn out the original USB hub and wreck two of the buck converters. So after putting in a couple of hail Mary orders just before Christmas, the replacement parts arrived before the holiday shutdown. With the replacement parts fitted and adjusted I decided that rather than mounting the hub on the mount over the polar scope cap, I would mount it on the scope. Initially I was going to mount it on the side opposite the finder scope to help balance the tube. In the end I couldn't decide how to mount the hub on the side of the tube so I thought that I would mount it on the tubes dovetail underneath the corrector plate so it will act as a counterweight.

A few photos:

When I get a chance I will post a short video of the power hub in position and operation.

[Stargazer33]

After having got over a very silly cold that didn't seem to want to fully come or just go away, I finally got out and made a short video of my new power distribution hub.

I still need to tidy up the wiring, but I haven't quite decided yet how I'm going to do that.

Anyway, here's the video:

Sorry for the dodgy camera work & editing!

With the mount slewing in both axis, two dew heaters, usb hub, guide camera, DSLR and DSLR coolbox with fan & Chinese peltier cooler. My set-up is still only drawing just over 4 amps.