[cwwozniak]

Originally Posted by Noyb

... Could even control it from the USB 5V power ...
...
This one predates computers and is still running strong ...

I thought computers predated USB cables.

[Who's Me]

I like it, have you ever dealt with Futurlec?
I usually use Digikey if radioshack doesn't have what I need locally but there site is not showing many pictures of the solid state relays.

[Noyb]

Originally Posted by cwwozniak

I thought computers predated USB cables.

The SS Relay predates Computers .. I still use them whenever I can .. (If I can find them in my old Parts box)
That was my first attempt at a USB controlled Power Strip .. Since then, I've switched to a Smart Strip.
Just cause I'm overly cautious ... There's a 1/8W series resistor hiding under the shrink tubing for the 5V feed.

Originally Posted by Who's Me

..Have you ever dealt with Futurlec?

No .. I couldn't find one on Radio Shack either.
That was the first SS Relay I found and I thought the price was reasonable.

I'd think 10A should work for you.
I didn't look, but probably cheaper than a 12V relay at Radio Shack.

Considering the reliability and the isolation to the power in the Computer ..
I'm thinking this is no place to be a cheap skate anyway

[Noyb]

Also … I wasn’t too fond of the failure alarm circuitry you showed earlier…
The path from the line back to the 12V in the computer would have kept me up all night

I didn’t have a chance to look for a smaller SS relay,
But maybe a smaller one could be used for a failure alarm... (they make ones for DC also) ..
Convert the AC back to DC to control the relay, Then use the output for the alarm.

But, Isn’t there a way to have the computer let you know if the processor is getting hot ??

[Who's Me]

I mentioned a few posts back that I will NOT be building the alarm circuit. It was just an idea I had, but I almost gave people heart attacks because of the safety problems.
I have been using Asus PC Probe to monitor temps but I had to set the alarm at 50c because it glitches sometimes and sets off the alarm even though I am running at 29~30c.

[Who's Me]

I was at Harbor freight and found this,
http://www.harborfreight.com/cpi/cta...emnumber=66093
The pump is rated for 7v. I hooked it up to my 5v rail with a diode and it runs fine drawing about 100mA. It keeps my cpu at the same temp as the 120v pump even though it is supposed to flow 22GPH less.

What effect will running at that low of a voltage have on the lifespan of the pump?

Now I have to find a use for the solar panel.

[JohnWill]

I can't imagine any adverse effects. That solar panel obviously doesn't supply maximum voltage all the time, so the pump would have to run on lower voltage anyway.

If you want 7V for it, you could use a voltage regulator to drop the 12V to 7V, and have the pump running on it's rated voltage. This would also increase the flow of the pump considerably. The LM317 is a good choice for this job, you can adjust it's output to anything you like. With a decent heatsink, the TO220 package will allow in excess of 1A of output current. Here's a simple circuit with a description: http://www.circuit-innovations.co.uk/LM317.html

[Who's Me]

I haven't really load tested yet but 5v seems to supply plenty of flow too keep my system cool. If I think I need more power I will use the LM317 as you said.
Oh, I got it I'll just add a wire from the 3.3 rail, that should be 8.8v....

[JohnWill]

Actually, that would be 8.3 volts unless you're using the new mach.

[Who's Me]

Um.. Yea, New math.. that's it.

Then I started wondering what you would actually get. I figured the 3.3 would pull the 5 down some.

So I pulled out an old 120W PSU and found that 5.15+3.32=4.15 And 5.15+11.65=0

[JohnWill]

You can connect to the +5V and +12V legs and get +7 volts.

[Who's Me]

Nope, I tried it 12+5=9....... 6.........4.......0

[cwwozniak]

Originally Posted by Who's Me

Nope, I tried it 12+5=9....... 6.........4.......0

With motherboard and drives pulling some current from the PSU, you should be able to do as JohnWill suggested and connect the (-) side of the pump to PSU's +5 VDC output and the (+) side of the pump to the PSU's +12 VDC output. That should put 7 VDC (12-5) across the pump. Some PSUs may not regulate properly with no load except the pump.

[Noyb]

It would make me very nervous to pull up on the 5V supply.
Supplies normally only source current .. Not sink it.
You're depending on the load on the 5V supply for sinking.

I would also be worried about motor transients back into the Computer supplies ...
Especially if they're going the wrong direction

[Who's Me]

I misunderstood you, I tested between ground and 5&12 tied together which soon shut down the PSU. I don't have a board to plug it into but testing between +5 and +12 does give me about 7v.

Noyb, Don't worry I would never rig my PC up like that, I just got curios about what would happen with different combination's. I'm testing on an old PSU that I don't care about.

I wonder what it would take to let the smoke out of it.