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Four-Motor Laser Spirograph

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Step 4: Attaching Switches and Potentiometers

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Potentiometers
Installing them is pretty basic, drill a hole the width of the post for each potentiometer, but plan it out so they don't bump into the motors. These have a hex nut that allows you to tighten them down from the outside of the case. A lot of potentiometers have a little vertical nub that rises from the top of the potentiometer, but keeps it from being flush against the case, I just snap them off with needle-nose pliers.

#1 & #2
I cut each potentiometer hole 1/2" from the base of the conduit box through a side panel (see pictures). Thread them through, align their terminals towards the middle, and tighten the hex nut.

#3 & #4
These two attach to the top panel of the conduit box,and it's important to make sure the main chunk of the potentiometer doesn't bump into a motor, since it's really compact in the box. Simply place them in-between motors.

On/Off Switches
These allow me to completely kill power running to any individual motor. They aren't absolutely necessary to kill a mirror, since a potentiometer turned all the way on (Max resistance) will kill the juice anyways. Stopping the motor by resisting all the electricity rapidly drains the batteries by turning all that power into heat. They add quite a bit of complexity to this mod, and if you don't feel like going through all the work for installing switches, you don't have to, but I find them useful.

Each switch attaches just like the potentiometers, drill a hole and thread on the hex nut from the outer side. Each switch should be pretty close to its potentiometer, leave room for the potentiometer decorative knobs to fit on top of their posts. Those knobs attach by a tiny screw in the side of them squishing onto the post.

The images below show how the on/off switches are oriented.

Master Power Switch (The Big Red Button)
This switch controls the power to all four on/off switches, and acts as a kill-switch in case you need to turn everything quickly off. Realistically, the switch I got is complete overkill and over-sized for this project, but it seemed like a fun attachment to use. Again, see the pictures for where the switch goes through. I get some comments about how it looks like it's about to activate a bomb.

Power Plug
Take a 9v power connector, drill two tiny holes for the positive and negative wires to enter the box, put them through, and hot-glue it down. A picture below illustrates what I mean.
 
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