We're back! Now that you've waded through the tedium of electricity 101, we can move on to making some toys!
Today we'll cover how to construct your own "hand-squeezer" (small dimmer). These are great for any lights 600W or less (6A or less). They're great for household lamps and especially great for practicals in your scene.
As a disclaimer, the previous four DV101 entries help you to understand the basics of electricity, but know that there is always a danger when working with electrical devices and electricity. Proceed with caution. If you decide to make your own dimmer, you do so at your own risk. These directions are provided merely as a guideline - anyone making their own assumes their own risks.
You'll need these supplies from your hardware store (anyone in the electrical department can help you):
- 1 - Single-pole standard household rheostat dimmer (push-in type is preferred, mostly, to the slide dimmer also usually cheaper)
- 1 Single gang EMT box (Handy boxes are nice they have rounded edges and are a little heavier for more robust use. Make sure you get one with punch-outs. You can also get an outdoor 1/2" single gang box. These are heavier, but will look prettier when you're done.
- 1 Single gang faceplate
- 1 Outdoor extension cord the shortest you can find (16/3 SJ cable), they're usually orange. I got a 10' for $7.49 if you can find a 3' or 6', great. Shorter the better.
- 1 pair wire strippers
- 1 flat-head screwdriver
- 4 wirenuts (three usually come with the dimmer)
All of these supplies, excluding tools, ran me $14.71.
You'll start by cutting the extension cord's ends off. You want to cut them about 12 inches from the ends so you have the plug and socket in two separate pieces with about a foot of extension still attached.
This will give you one 12 inch length with a male plug and one 12 inch length with a female plug. You can throw away the cable from the middle or save it for use some other time.
Notice that inside the main orange insulation of the cable there are three separate wires (green, white, black).
Next, you want to cut away the main orange outer insulation ONLY from about 3 inches from the cut end on each side of the cable. This exposes the three wires inside. This is VERY tricky to do without cutting the insulation on the individual wires you ONLY want to cut the orange. Using a razorblade and cutting very carefully helps. I used the wire strippers, but you've got to be very careful. You do not want to cut the green, white or black insulation.
Do this on both orange cables.
Now, using the wire strippers, you'll strip away the insulation on each of the three wires about 1 inch to expose bare wire. Do this on all three wires (black, white, green) on both cables.
When you're done with all that you'll have three wires, each stripped 1 inch on both pieces of cable.
Next up, take the single-gang EMT box that you bought and pop out one of the punch outs (if you bought the outdoor box, you won't have to do this, the holes will already be there). You'll need to tap it loose with a screwdriver (pushing in like a soda can top) then wiggle it until it breaks off. Some are much harder than others, but it breaks off eventually.
Feed both stripped ends of the wires into the hole.
Now one end of each 12 inch wire is in the box and the other is sticking out.
You'll now start connecting wires inside the box. Pay special attention here
.
Start with the white wires. Put the two white wires (one from each orange cable) together, give them a little twist and then slip them in the wirenut. Twist the wirenut on and make sure it's on snug give it a little tug and make sure it doesn't pull off.
Now the two white wires are connected together, get out your dimmer from the package.
Look on the back of the dimmer
. IF it has a green wire (some don't), then you'll connect that green wire with the other two green wires (one from each side of the orange cable) twist all three together and twist the wirenut on. If the dimmer doesn't have a green wire (or it could be bare wire, which you should connect in as if it were green), then don't worry just connect the two greens from the orange cables together and put the wirenut on.
Now the dimmer has two black wires coming out of the back of it. Connect ONE black wire to ONE of the black wires from the orange cables (doesn't matter which one). Twist them together and put on the wirenut.
Next do the same thing with the other black wire. Connect the ONE remaining black wire to the ONE remaining black wire from the orange cable (it doesn't matter which black wire on the back of the dimmer is connected to which black wire from the orange cables just so long as each black wire from the back of the dimmer is only connected to ONE of the black wires from the orange cables the other black wire from the back of the dimmer is connected to the other black wire from the orange cable). Each wire from the back of the dimmer is now connected to each of the orange cable lengths. Now you have FOUR connections all greens together (2 or 3 wires in one nut), all whites together (2 wires in one nut), one set of blacks (2 wires in one nut) another set of blacks (the other 2 wires in one nut).
Now, tuck the wires inside the box.
Using the two screws that came with the dimmer, screw them into the holes in the EMT box (it will line up perfectly).
Now put the faceplate on and secure it with two screws and push the knob onto the peg.
And you're done!
Now you've got a hand squeezer dimmer you can hook up to incandescent lights (not fluorescent) and dim them up and down. This is great for practical lights on a real location. Cheap and handy!
All the best,
Jay Holben
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Previous Blogs:
10/09/2007 Who is This Guy?
10/12/2007 The Camera Conundrum
10/16/2007 The Digital Seduction
10/19/2007 Why I Teach
10/23/2007 More Detail on 24p
10/26/2007 DV101 Continued: Polarizers
10/30/2007 Spooky Digital Photography
11/02/2007 Smoke and Fog Part One
11/06/2007 Smoke and Fog Part Two
11/09/2007 Film Look: Widescreen Part One
11/13/2007 Film Look: Widescreen Part Two
11/16/2007 Film Look: Widescreen Part Three
11/20/2007 Adventures in Lighting
11/20/2007 First Time DV
12/03/2007 Choosing the Canon XL2
12/07/2007 DV Expo Follow-ups Part 1: More on the Doc Filmmaking Panel
12/11/2007 Electricity 101
12/11/2007 Electricity 101: Part II
12/18/2007 Electricity 101: Part III
12/21/2007 Electricity 101: Part IV