Outlet 60 Minute Timer

Outlet 60 Minute Timer

As I was browsing reddit today, I found this nice simple project, an Outlet Timer. I remember leaving the hot glue gun on one day, and finding it the next day, still running as hot as could be. The glue that came out of it was orange, and I know that things would have been bad if I didn’t catch it when I did. Typically I try to be as cheap as possible, but for the importance of this project, I didn’t mind investing the $27.

Here are the parts that I used for this Outlet Timer

In true DIY fashion, I’ll go through the steps that i used to make it.  I first wanted to find out which wire was Hot (the conductor that is switched when you switch on/off the power strip.  I first pealed back the insulation, being careful not to nick any of the wires.  I picked this location so that it was pretty close to the strip.

Under the insulation, we find, 3 wires (white, black, green).

In my case, the switch was connected to the black conductor (I could tell by measuring the conductance between the black wire, and that socket, when I switched on/off the power strip).  I cut the wires, with a pair of wire cutters, and stripped the recommended length of conductor for the countdown switch.  After feeding both wires through the 1 Gang electrical box, I inserted the trimmed black conductor into the countdown switch.

Inserting Black wire into countdown switch, note that both ends of the power cord have already been fed through the 1 Gang electrical box.

After that, I secured both green wires together using a WireTwist wire connector, and I did the same for the white wires.

Securing green and white conductors with wire connectors

At this point, I wanted some strain relief, so that things don’t come undone if someone accidentally pulls the power strip.  So I took 2 black zipties, and fed it through the 1 Gang electrical box so that the power cable will be secure against the box.

Stress relieving the power cable using zipties

By far the hardest part of this project was screwing the Countdown switch to the 1 Gang electrical box.  Those flat-head screws weren’t fun.  I wrapped it up by putting the faceplate on.  I did a quick sanity check, by using my multimeter and checking conductance before it has been plugged in.  Ground and Neutral were always connected, Hot was only connected to the wall if both the timer was on, and the switch for the power strip was on.  I tested it using my plug tester, and it tested out 🙂

Price list

As always, proceed at your own risk.  If you make this project, and it messes up, you take full responsibility.

Outlet 60 Minute Timer

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Case of the future

They often say that you should pick a case before you design PCB’s, so that you know where it will fit, and how. I believe I have found a very cheap, DIY case, that you can go and pick up from your hardware store.

Insert, the 1 Gang Electrical Box. Typically used for housing electrical connection in your walls, these cases are about 0.24 a piece. Lids for them run an additional $0.60, bringing the total cost of this case for your microprocessor to under a dollar. I picked up the case and lid from both Home Depot and Lowes. Home Depot has a blue 1 gang box that has a little more flat space at the bottom. Both cases have punch outs where you can have your wires come out, perfect for a robotics project 🙂

I’ve been a big proponent of getting PCB’s designed, particularly with Kicad. But doing hobbyist electronics shouldn’t be about making the prettyist PCB wiring with the optimal spacing and clearances. It should be about getting your prototyping board with wires out, wiring it up so your project works. Once it works, you can expect it to continue working.

Documentation is important (especially if you want to come back to it), but your main goal is to accomplish your project without going broke.

You may make mistakes, so if you make them, try to make them as cheaply as possible. That is where my interest is headed right now. I’ll try to post more often now, maybe even daily, just to keep me focused on what I’m working on, and to share my ideas 😛

One last comment: RadioShack Prototype board Fits in this case http://www.radioshack.com/product/index.jsp?productId=2102845 as well as DipMicro’s 70mm x 50mm http://dipmicro.com/store/PCB-UNI7H. If you get the grey 1 gang box from Lowes, RadioShack’s protoboard won’t sit flat on the bottom unless you take out a tab. Or you could do as I will do, and mount it to the top 😛