Are you sure I need a relay on this circuit? It is only being used as a turn on signal for both the USB hub and the P2140 PSU. No real power draw from either circuit.
I'm not sure how you are wiring everything but Amps can draw as much as 50mA each and many spike that level if the main fuse in the amp blows. I am told one brand of amp spikes as high as 500mA. It will also protect your CANBUS adapter in case of a short circuit. I'm not sure what the trigger current is for the 2140 but to me, a $5 relay is good insurance money, that's all.
Also you have a delayed 12v out for amps from the 2140 plus you'll need clean 5V supply from the 2140 for the hubs so I'm not sure that you need to trigger more than just the 2140 with it but that depends on how your wiring everything. The PAC RP4-VW11 (for example) gives you 1 amp to work with on the acc. output but regardless, IMO, a $5 relay is not still a bad idea to protect the adapter.
P2140 primary circuit is powering the Mac Mini and the xenarc 8" LCD
P2140 secondary circuit is providing a turn on circuit of the Monsoon Amp
-- The link has the details if you are not familiar with the Monsoon Amp
-- Bottom line is the amp turn on signal is a 6v input through the negative speaker terminal on the amp input
DC-Powered 4-Port USB Hub CNX-P5USB (12v and 24v systems) is powered directly from the radio harness Positive and Ground circuits. It is internally regulated and should handle the direct power.
The radio harness derived ignition switched line will be used as a turn on signal for both the CNX-P5USB and the P2140.
That sounds like it will work. From what I can tell, the hub you are using does not require a trigger wire, it will sense PC voltage on the USB line. If you do decide to trigger it, I don't see the specs for the current draw of the trigger line. I think I would just try the voltage sense option first. Being that the harness adapter likely gives you 1 amp to work with, you technically don't need to relay it other than it would give you some added protection for that adapter.
That's a lot of work to hang onto an OEM amp but I get it, the speakers have to be replaced at the same time as the amp so it really adds to the project time/$$. I just picked up a Buick Rendezvous for my wife (ugly POS but I got it dirt cheap & she likes it???) I think it may have the monsoon amp in it, haven't checked yet, but if so, when I add a sound system to it, it's gone. But I have amp/speakers etc sitting around collecting dust so it's just some extra work, not a ton of money.
Regarding that hub you chose, awesome hub but a lot of coin. Just remember 4 ports is not a lot in a carpc, I have 12 and they are full (I am running a laptop though which adds extra external components).
If you end up needing more ports and don't what to layout that coin again this works great with less expensive over the counter hubs: http://store.mp3car.com/Carnetix_CNX..._p/pwr-016.htm
My MAC mini is installed and working.
Have to cleanup some wiring, install the USB hub in the glove box, and install the Xenarc 8" monitor in the dash.
Integrated the MAC mini sound output into the stock Monsoon Amp and they are getting along just fine.
Taking my time with this project paid off. I did a lot of bench testing and planning.
Here is where I am at:
Nice! glad to see you got it up and running. The only thing I see that concerns me is the hanging RCA cables for 2 reasons 1) they could come unplugged while driving from the shock of the bumps 2) it appears that the weight of the Y adapters,plugs & cords are pulling down on the factory wires. I would suggest zipping them up to something. Nice job on the switches in the dash, Vdub is great for leaving extra knockouts to work with.
The next step is to mount the USB hub into the glove box and install the Xenarc 8" LCD into the dash.
But I have a problem that plagues all VW IV owners, the dreaded foam in the A/C vents.
I have ordered a new airbox and all associated hardware.
I am going to create a DIY thread for removing the dash and fixing this problem the right way. I plan on replacing all under dash items including the heater core, blower fan, airbox, and A/C evaporator.
I should have that new car smell and no more foam.
I will post a link to that thread when I get it started.
Here is my new thread, DIY: Foam from the A/C vents.
I will continue to add to this thread the applicable tasks of mounting the video monitor in the dash and the USB hub in the glovebox.
Ok I am back from ripping the dash out and replacing the airbox, evaporator, fan, and heater core.
No more foam coming from the vents and no more old car smell.
I will be installing my 8" LCD in the dash and the USB hub in the glove box.