This will make 1 dimmer switch box. This should only be used with lights or other low wattage items NOT items using motors or drawing a lot of power. As with anything electrical, consult an electrician before starting this project.
Gather the following: 1 plastic or metal junction box, 1 dimmer switch, 1 double outlet, 1 length of 14/3 wire, 1 3 prong plug, 1 face plate, 1 wire nut (not shown).
The dimmer switch goes between the outlet and the cord using the hot (black) wire. In other words, connect the black wire from the cord to one of the black wires on the dimmer switch using a wire nut (yellow cap). Connect the other black wire from the dimmer switch to the GOLD screw on the outlet. If there is no gold screw connect it to the screw on the side of the smaller of the two prong openings.
Connect the white cord coming from the cord to the SILVER screw or the screw on the side of the larger of the two prong openings.
Connect the green (or bare) wires from the dimmer and the cord together and connect them to the ground (green) screw on the outlet.
Screw the outlet and the dimmer switch into the junction box. Knock out one of the openings in the back or bottom of the junction box and feed the cord through. I tie the cord in a loose knot near the outlet before feeding it through to keep it from accidentally being pulled out and off of the outlet.
Feed the cord through the cover of the plug if necessary. Connect the black wire to the gold screw, white
wire to the silver screw and ground/green wire to the green screw.
One dimmer box ready for duty.
You are so clever. I look forward to see this as another great success!