Electronics 101 question

[Sam Peck]

Hi all, 

In the next part of my Arduino project, I'd like to monitor and control the 120V 15A wall power. Monitoring the power seems pretty straightforward, with a split coil CT setup as recommended from Sparkfun.com. Controlling the power with a relay seems simple, too, but I'm not sure the best way to address building a control board, schematic located here.

http://www.sparkfun.com/tutorial/Outlet/RelayBoard-Large-v11.pdf

http://www.sparkfun.com/tutorials/119

I'm not sure what some of those parts are, but I was thinking that I'd build up a small breadboard with all of the components. Is there an easier way to do this? Or is there an easier way to control 120V 15A power from the Arduino? 

Thanks, 
~sp

[Tom Gralewicz]

We have an easier way to control 120V at 15A, there are a bunch of solid state relays at the space.  They are expensive to buy, but the ones I pull from machines at work are free.  You can connect the input directly to an Arduino output pin and turn the load on and off.

The only thing you need to watch for is if you are controlling a large motor or other inductive load, then you need a snubber circuit across the relay to clamp the spike when you turn it off.

http://www.digikey.com/product-detail/en/AQA421VL/255-2980-ND/2364685

Tom

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Tom Gralewicz
Miller Electronics Recycling
(414) 380-1716
www.deadcomputers.com

[Ron Bean]

>is there an easier way to control 120V 15A power from
>the Arduino?

The easiest way is with the "Powerswitch Tail" from either Sparkfun or
Adafruit (and probably others). It's kind of expensive, but very simple
and self-contained.

YMMV with the solid state relays. Since they're free, try them and see
what happens. We tried to use one to control the CNC router, but for
some reason we never got it to work right-- not sure if it was the
relay's fault or not.