The Most Useless Machine
From MAKE Magazine
This project first appeared on the pages of MAKE magazine.
Through its one meaningless act of defiance, it speaks volumes.
- Author: Brett Coulthard
- Time required: 3 hours
- Difficulty: Moderate
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Last year I saw a video of the "Leave Me Alone Box" built by Michael Seedman. Flip its switch on, and an arm reaches out of a door to turn the switch back off. To paraphrase The Terminator, that's what it does, that's all it does, and it will not stop until its circuit is dead.
I had to have one of my own, so I made one. Seedman's design uses a microcontroller to run two servomotors: one to open the lid, and another to push the switch. This makes for an impressive performance, but seemed too complicated, and actually, his circuit remains powered even when the box is idle.
For existential purity, I wanted a super-simple machine that really turned itself off. So I came up with a single-motor design controlled by a 555 timer chip, with a curved arm that both lifts the lid and flips off the switch. I called it the "Most Useless Machine" and posted it on Instructables along with a YouTube video of the box in action. The project soon went viral, attracting millions of viewers, thousands of comments, and many builds and design variations. Whew!
Along the way, Instructables member Compukidmike came up with an even simpler version that dispenses with the 555 circuitry entirely by using a gearmotor and two switches. The resulting project, presented here, is the ultimate in technology for its own sake, a minimal assemblage of parts that, through its one meaningless act of defiance, speaks volumes.
A complete parts kit including a laser cut acrylic case is available at http://frivolousengineering.com/?page_id... for only $30.00!
Sections
- Prepare the box.
- Determine the layout.
- Mark positions and make the arm.
- Build the circuit.
- Mount the toggle switch.
- Test-fit the motor and switches.
- Assemble and adjust.
- Close it up.
- Customized Uselessness
- The Machine That Broke Stephen Colbert's Heart
Files
Tools
- Diagonal pliers
- Drill
- Drill bits, 1/16", 1/4"
- File
- Hobby knife
- Hot glue gun, with hot glue
- Jigsaw or coping saw, or scroll saw
- Miter box
- Pencil, with eraser
- Ruler
- Sandpaper
- Scissors
- Screwdriver
- Soldering iron
- Table saw or handsaw
- Wire strippers
Relevant parts
Relevant parts (continued)
- Wood glue or cyanoacrylate gel glue or other good permanent glue for wood and plastic
- Alkaline battery (4), AA
- Battery holder, 4xAA RadioShack #270-391, radioshack.com
- Insulated wire, 24-gauge, different colors Scavenge from dead telephone cable, Ethernet cables, thermostat wire, intercom cable, and anything with tiny colored wires. You can't have too many different colors of wire.
- Hook-up wire, 22-gauge insulated, stranded
- Gearmotor part #GM2 from Solarbotics, solarbotics.com, or #SBGM2 from the Maker Shed, makershed.com. You can also use a standard R/C servomotor modified to ignore signal input and allow for continuous rotation, if it doesn't already. See makezine.com/23/uselessmachine for sources and instructions. A GM2 is less expensive, but if you have an extra servomotor already, the mods are easy.
- Gearmotor mount, with mounting bracket Solarbotics #GMW and #GMB28, if you're using the GM2 gearmotor.
- Toggle switch, DPDT or DPST or salvage this and the micro switch from common electronics.
- Lever micro switch, SPDT
- Wooden box, small Lid must be large enough to fit the battery pack, motor, and arm in resting position (down). The one I used was purchased at a Dollar Giant store. If your lid isn't hinged, you'll also need some small hinges.
- View:
- Paginated
- Full width
Edit Step 1
— Prepare the box.
¶
One half of the lid hinges up, while the other half carries all of the machine's workings. The workings all mount onto the same piece so that they'll stay aligned.
Remove any latches and hinges on the box's lid.
Cut the lid approximately in half through the middle crosswise, undercutting at a slight angle so that the hinged half won't bind when opening. Before you cut, make sure the machine half has at least enough space to fit both the motor and the micro switch lined up lengthwise.
Edit Step 2
— Determine the layout.
¶
Use the pencil to draw scale paper templates of the motor, toggle switch, micro switch, and the machine half of the lid, all in side-view, and cut them out. Also cut a template for the motor's mounting wheel or horn, and mark the axle on both the motor and mount templates.
Use the component templates to figure out the shape of the arm and how everything should attach to the lid. Download sample templates in the Files section above, or at makezine.com/23/uselessmachine.
You want the back of the arm (or a mounting horn) to push against the lever switch when it's retracted. Then the arm should rotate and clear the lid while its "hand" swings over and pushes the toggle switch.
Cut templates for the arm and for a standoff bracket that holds the motor and the lever switch. Refine their shapes and sizes and move the pieces of paper around until you're sure that they all work together, while still leaving room for wire connections.
Edit Step 3
— Mark positions and make the arm.
¶
Mark the positions on the templates where they meet: the toggle and bracket's position on the lid, and the motor and switch's position on the bracket.
Trace the template shapes onto 1/4" plywood and cut the pieces out. File and sand the edges smooth.
Mount the arm to the motor's mounting wheel or servo horn. Drill 5 pilot holes in the arm and mount it with small screws (usually included).
Measure and mark a centerline across the machine half of the lid, perpendicular to its cut end. Then mark the toggle's distance along this line, following its position marked on the templates.
Edit Step 4
— Build the circuit.
¶
Now it's time to fire up the soldering iron. If your motor already has leads attached, solder them to each of the 2 middle legs of the toggle switch. Otherwise, cut, strip, and solder wire leads between each motor terminal and the middle toggle pins; 4" long is plenty for all connections in this circuit, and you may want to shorten them later for neatness.
Solder a short jumper wire diagonally between 2 opposite corner legs of the toggle switch, then solder separate leads to the remaining 2 legs at the other corners.
Edit Step 5 ¶
Solder the 2 free leads from the toggle to the lever switch. Connect one to the common tab (marked C), closest to the lever's pivot. Connect the other lead to the normally closed (NC) leg, farthest from the pivot. Don't connect anything to the normally open (NO) tab in the middle.
Solder the battery pack's leads to the 2 legs at either end of the toggle. The circuit is complete! Test it by loading batteries into the pack. The motor should run, the toggle should reverse its direction, and the lever switch should shut it off in one direction. If it all checks out, remove the batteries, leave the toggle thrown in the direction that the lever interrupts, and mark or note this direction on the motor.
Edit Step 7
— Test-fit the motor and switches.
¶
Hold the wooden bracket, motor, and lever switch in place against the lid so that they align properly with each other and with the toggle. Mark their positions with the pencil.
If the motor turns in the opposite direction from what you anticipated while determining the layout (if the interruptible direction turns the arm out, not in) you should reverse the connections to the motor, or else position the motor the other way and arrange the pieces in mirror-image on the opposite side of the box.
Edit Step 8
— Assemble and adjust.
¶
Temporarily hold all the pieces in place with a bit of hot glue. Put the lid on the box with the other half off, load the batteries, and check to see that everything works perfectly (which is unlikely).
Tweak the components' placement and the shape of the arm as needed, ungluing and regluing with hot glue, until everything does what it should. You may need to file down part of the arm so it clears the bottom of the box, or fine-tune the position of the all-important micro lever switch.
When everything checks out, mark the final locations. Then mount the motor to the bracket with its included screws and attach the other components in place with permanent glue.
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Comments Comments are onturn off
Guide
There's a circuit diagram in the Instructables.c
http://www.instructables.com/id/The-Most...
Direct image link: http://d37i651vg1sd88.cloudfront.net/FM4...
R1 is the motor/servo
Oh, one last thing. After searching for ever to scrounge a microswitch that would do the job, I found 3 under the buttons in an old Dell mouse. Old mice are easy to find (I have 4 in a drawer). I found it easier to snap the mouse's circuit board than de-solder the 3-pin switch, then I just soldered wires to the pins as normal. I used the wires from the mouse cord.
You can rotate the design so the box opens normally, but you have to watch out for space/clearance issues. I did this and then realized that I liked it even better upside down:
http://www.youtube.com/watch?v=IyIDDnlH6...
I hacked off a Barbie's arm for style points and used boiling water to soften and reshape it (cooling in ice water fixes it pretty well) so it had a good curve to open the lid and hit the switch. You'll need a ramp up to the lip of the lid so the moving arm will open it. Everything used was found or scrounged, so it only cost me time and sanity.