Make an Inline Lighting Dimmer for $7.25

Introduction: Make an Inline Lighting Dimmer for $7.25

About: I'm a tinkering filmmaker who likes to build stuff for my films.

For filmmaking purposes, controlling how much light comes into the lens is pretty basic. Opening or closing the iris (or aperture) of the camera can control the total amount of light, but what if you want to be more selective? You might need to control light sources individually and that's where a dimmer comes in.

Simply plug whatever light you wish to dim and crank down (or up) on this very handy gadget. Made easily and cheaply with hardware store parts, this little dimmer can handle any light up to 600 watts.

If you're not a filmmaker, this gadget will still handle most of your light controlling needs.

Step 1: Parts List

These parts can be found at any hardware store (Lowe's, Home Depot, Ace) or Wal-Mart. In my experience, Home Depot has the best prices, but Wally World is known for deals on stuff you didn't even think they had.

- 6' 2 prong power cord, $1
- "Old Work" PVC gang box, $0.72
- Lid for gang box, $0.54
- Rotary Dimmer, $5

Step 2: Tools

Not very complex here as most have something that will fit the bill already.

- Multi-tool (I just used the pliers and Phillips head screwdriver in this)
- flathead screwdriver
- wire cutters/strippers

Step 3: Prep the Dimmer

All we're doing here is cutting off the exposed ground wire and twisting the ends of the two black wires.  It is now ready to be attached to the cord.

Step 4: Prep the Cord

Cut the cord from 1' to 1.5' from the female end. Separate and strip the four wires.

Step 5: Prep the Box

Using a blunt instrument, break out one of the die-cut holes.  I used the pliers from the multitool.

Step 6: Run Cords Through Hole and Add Strain Relief

After both cord ends are inside the box, tie each one in a knot.  This will prevent the cords separating from the dimmer if they get yanked on. 

Step 7: Connnect Cords to Dimmer

Find both ridged wires and twist them together, adding a screw nut.  Take the remaining two wires and twist them to the black wires from the dimmer (it doesn't matter which ones).  Add the two remaining screw nuts.

Step 8: Squash Guts Into Box and Attach Lid

It will be a tight fit, but push everything down in the box and screw in the dimmer.  Brute force may been needed on this step, but I like the compact result.

Step 9: Attach Knob and You're Done!

The knob is a press fit.  Happy dimmering!

Like this type of thing?  Check out The Frugal Filmmaker for more!

Step 10: Here's the Video Version...

1 Person Made This Project!


  • For the Home Contest

    For the Home Contest
  • Game Design: Student Design Challenge

    Game Design: Student Design Challenge
  • Big and Small Contest

    Big and Small Contest



8 years ago on Introduction

You can buy a dimmer for less than $1.50 on ebay. It is an online switch the takes a couple of minutes to attach to the lamp cord. You just need a philips screw driver and a razor blade to cut the wire. Comes in white and brown and you can put it anywhere on the cord. I have mine a couple of inches from the lamp so I don't have to search for it.


Reply 6 years ago

Although those are cheap, I believe they're only three position: High, Low, or Off.
The dimmer in this instructable is far more adjustable, however unsightly or bulky it may be.


6 years ago

Could I leave one wire in the chord uncut, and splice in the dimmer just breaking one of the wires in the pair? I would imagine that could eliminate 1 unneeded cut in the circuit.


7 years ago on Step 3

does this control a soldering iron well?


11 years ago on Introduction

This also won't work nearly as well on LED or CFL bulbs unless they are rated to dim, and even then it's not as straight forward as incandescent bulbs.


12 years ago on Introduction

This could be used to control a solder iron but I'd use a stranded socket, a double box, and a 3 wire cord to allow for an earth connection. My iron has one and I consider it an important safety feature.


12 years ago on Introduction

Nice and straight forward Instructable. The only thing you don't mention is that using a dimmer will change the color temperature of the light produced by the bulb. The more you dim down the bulb, the lower the color temperature (more orange) the light will be. From an audio standpoint, dimmers also make bulbs hum a bit.