Steve's USB and Power Distribution box

[kirkster501]

Here is where I have got to so far after starting earlier today, about eight hours of work so far.

I have fused the outputs  of the PSU - both the +12V (that I have adjusted to 13.4V) and common lines in preparation for a crowbar overvoltage circuit I am going to install across the 12V-Common rails.

 

 

[gnomus]

Very nice Steve.  Much better than the crude piece of garbage I put together. 

[VectorQuantity]

Looks nice.

Thats a good choice of Hub, I put the same one into a homemade powertank a couple of years ago and its worked flawlessly.

A pity StarTech don't do a flush mount version, would make the cabling easier.

[Colinlp]

Is that just a 12V supply, looks very nice I must say, where did you get it from?

I'm confused/intrigued to see how you will utilise those USB ports from the outside

[kirkster501]

14 minutes ago, Colinlp said:

Is that just a 12V supply, looks very nice I must say, where did you get it from?

I'm confused/intrigued to see how you will utilise those USB ports from the outside

Hi it is from Amazon - an LED lighting PSU with 12V outputs and is the 20A version which shoudl be ample.  The output voltage is adjustable too from 12v up to 14V.  I set mine to 13.6V.

http://www.amazon.co.uk/Sourcingmap-Driver-Power-Supply-Switching/dp/B008DFAMWA?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00

Build is still in progress.

[kirkster501]

Added the crowbar protection cct - almost finished,

[kirkster501]

I got the crowbar circuit design from here:

http://www.mds975.co.uk/archive/amateur_radio_projects_07.html

Cost me about £7 to make that little circuit but worth it when you think of the amount of gear my power/USB box is powering up - Atik cameras/filter wheels/mounts - £1000's...... 

[NickK]

On the power switches - make sure you're not going to accidentally switch them by brushing against them - the big rocker looks ok, but the little finger switch may cause issues.

 

[kirkster501]

I also need to work out how the green LED in the switches work.  The switch does work on the live (in and out).  I thought the current flowing through would light the LED but it doesn't.

[Vox45]

3 hours ago, kirkster501 said:

I also need to work out how the green LED in the switches work.  The switch does work on the live (in and out).  I thought the current flowing through would light the LED but it doesn't.

Not sure if you are talking about the rocker switch with the LED (right ?) because I had the same issue

On my switch, there are 3 prongs: the middle one should get the power input, the copper one should go to negative/ground and the 3rd one would go to the device that needs power. I was only using 2 out of the 3 prongs and the LED was not lighting up... hope that helps.

[kirkster501]

Thanks! Will check into it later on.

[kirkster501]

Great - that did it many thanks!

Now, the main DPST switch not lighting either:

http://www.ebay.co.uk/itm/261445376275?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Any ideas on this one?  This is MAINS as well not 12V.  I will look into it further.

[MarkyD]

16 hours ago, kirkster501 said:

Great - that did it many thanks!

Now, the main DPST switch not lighting either:

http://www.ebay.co.uk/itm/261445376275?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Any ideas on this one?  This is MAINS as well not 12V.  I will look into it further.

Unless there are two extra contacts for the 12V illumination you can't light this one up using 230V.  If there are you need to source the output 12V of the power supply that you are switching.  If they are designed for 230V then they usually have a Neon as the illumination which will sit across the NO contacts

--

Mark

[RuralBill]

Watching this thread with great interest. 

Cheers

Bill

[1CM69]

On 4/26/2016 at 22:04, kirkster501 said:

I got the crowbar circuit design from here:

http://www.mds975.co.uk/archive/amateur_radio_projects_07.html

Cost me about £7 to make that little circuit but worth it when you think of the amount of gear my power/USB box is powering up - Atik cameras/filter wheels/mounts - £1000's...... 

Hi,

an old thread I know but I am struggling to build my own crowbar circuit, came across your post but the link is dead. Do you have any further info?

My power pack outputs 13.8VDC and if all my connected equipment is running at the same time, it'll draw 6.65A.

I wish to limit over voltage to 14v.

Could you help with the formulas so I could then order the components?

Regards..,

[Horwig]

On 2016-4-26 at 22:04, kirkster501 said:

I got the crowbar circuit design from here:

http://www.mds975.co.uk/archive/amateur_radio_projects_07.html

Cost me about £7 to make that little circuit but worth it when you think of the amount of gear my power/USB box is powering up - Atik cameras/filter wheels/mounts - £1000's...... 

Love the link, it takes me to the conservative party website, they must be desperate for hits today

Huw

[1CM69]

Yeah definitely desperate ?

[kirkster501]

Just google "dc power distribution crow bar circuit"

I did not follow any formulas, just built a 13.8V cct from a design at that link which as you say has now gone dead.  There are others if you google that phrase.

https://www.eevblog.com/forum/beginners/12v-crowbar-circuit/

for instance.

[kirkster501]

... and just to add that the power/USB box is working perfectly still.

One wish is that I wish I had more USB ports and used the 10 port USB powered hub instead.  The USB ports can get consumed very rapidly.  For example, I have used up six up already  - Mount, CCD, CCD FW, Guider, Polemaster, Focuser - and now I need two more for another camera and another focuser if i want to leave everything permanently connected and not swapping USB's out (always a fraught endeavor....)

[1CM69]

21 hours ago, kirkster501 said:

Just google "dc power distribution crow bar circuit"

I did not follow any formulas, just built a 13.8V cct from a design at that link which as you say has now gone dead.  There are others if you google that phrase.

https://www.eevblog.com/forum/beginners/12v-crowbar-circuit/

for instance.

After lots of research and a very late night last night/this morning I am building a OV protection circuit but a different design.

I'll be using an LTC4365 & my circuit will be as fig13 here: Linear LTC4365 Datasheet

I will also be adding a LED to the FAULT pin as shown in the schematic here: DEMO MANUAL DC1555B

I gained an invaluable wealth of information & help from the guys at All About Circuits and my thread there is: SCR Crowbar Circuit Help

 

I will of course post up my progress, prototyping etc.. on SGL with it's own thread.

Regards..,