Project: Power House

[AmEv]

So, we got two Wills here now?

This MIGHT get confusing.....

[SXRguyinMA]

including you, 3 actually lol

[billygoat333]

[AmEv]

Numbers.
SXR.

Who's the 3rd? Not me.

[billygoat333]

would be me. hence the smiley.

[peterlonz]

Some great ideas here.
I am not sure how, but a 24V supply would be advantageous, maybe most easily achieved by including a separate transformer, plus rectifier & regulator which could be an adjustable type for greater utility.

Re the multimeter for digital voltage readout: that is the best & lowest cost approach although cutting the PSU panel to accomodate needs a bit of care. You also usually have a built in transistor tester & sometimes a capacitor tester & auto-ranging for a few more $$$. The other thing is that it may be better to retain the battery supply for the meter, most work on 9V & I suspect a ground connection for alternative supply might introduce spikes or other unwanted & hard to find "interference".

I have wrestled with the issue of the best & most easily used connectors when building a similar unit. At first I also used binding posts but they are a pain when a quick connection is required. Finally I decided that screw down clamp terminals were all round the most convenient, just stick your wire in the hole & clamp it without damage by a screwdown. Best of all the whole connector is pretty well protected against accidental contact by the plastic moulding. Oh yes, & although not elegant top mount is the most convenient.

I never thought about a fan (foolishly) believing that a bench supply is very rarely in use for more than a few minutes at a time. That's dumb & limiting when fans are cheap. Here (in Australia) however, you might need to incorporate a 1 mm square insect proof mesh - those damn insects love warm hard to access places.

I'd love to see more detail about low cost lighting effects.
Well done.

[peterlonz]

My final comment:
This has been a wonderful project to follow, & see how community involvement has helped.
The "24V+" solution is great even if it meant a "board from China".
I was not surprised to see you experienced some "interference" on your meter (see my other post) but pleased you sorted it.
Personally I don't like the cramped space but recognise how that came about.
Also I don't like the hard edged box design which I think proved time consuming to make, although very flexible, & the materials are easy to work.
All round a very well made & super useful bench PSU.
Well done & thanks for the ongoing detailed explanations - I guess that applies to everyone here.

[SXRguyinMA]

Thanks for you comments Peter and thanks for checking it out!

[SXRguyinMA]

ok well now that the weather has warmed up I've noticed the readings are off again. The warmer it gets, the lower the readings. It'll be ~75º in the room, and with the fan in the window as night comes it cools down to ~65º and the readings go up by a volt or so on the 12v. right now it's ~77º, the 3v is reading 3.3, 5v is 4.56 ans 12v is 10.47. The actual voltage is correct though.

It would appear that I need to make some sort of temperature compensation for the ATMega. Apparently it's ADC is affected by temp. More on this later.

[Swankrg]

Resistors change values with temperature changes. Try using precision resistors

Great project and documentaion.
What LCD did you use?

Thanks