Picture of The Most Useless Machine EVER!
And yet everyone wants one!!!?

AKA:  The Ultimate Machine!

Get Your Parts Kits and Machines:

Update Oct 31, 2012:

Now Available At the Maker Shed

"Weird Al" Yankovic Sez:  "I never realized till now how much I needed one of these."

AS SEEN ON TV!  Make Magazine's amiable editor-in-chief, Mark Frauenfelder demonstrated The Useless Machine on the Colbert Report!

Useless Machine Featured in Vol 23 of Make Magazine!

Thanks everyone for all the cool comments, suggestions and all the videos! Keep 'em coming.

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Step 1: Background

Picture of Background
Also known as The Ultimate Machine: Claude E. Shannon built the first one based on an idea by Marvin Minsky.

After seeing a video of such a machine I just had to have one of my own.

The only design I could find uses a PIC microcontroller but I consider this to be overkill (not knowing how to write code for micros may have had some influence on my humble opinion...).

Additionally, the microcontroller version really doesn't shut itself off. It's circuit remains powered even when the switch is in the off position.

Knowing a little bit about servos and basic electronics, I felt sure that I could build the machine using a simple analog circuit.

My main goal however was to have the machine REALLY turn itself off.

The machine in THIS instructable accomplishes that!
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lukeyj153 years ago
I found something similar. Make sure you watch until the end.

This one is cooler XD

what happened there, AI!!!!!!!+ wheels.

it's the useless-inator... i thought doofenshmirtz gave up.
ah well...
get the sledgehammer
haha saw this a couple months ago, still funny!
dude this thing is sico!!!
nice video
I saw this video two days ago, and made one yesterday using Lego Mindstorm, and saw this instructable today
The exorcist meets the most useless machine ever. lol

Thanks for the nightmare :)
jimdkc15 days ago

Here's an animated schematic of the switch-only version (without crossed wires!!!) that explains how it works:

Doc_Cottom15 days ago

I used to have one years ago. It was a coin bank. If you laid a coin on the box the door would open, the fingers extend, grab the coin and slide it into the bank and the door would shut.

UselessCan1 month ago

We have one on Kickstarter if anyone interested. It's kit with 45 pieces that you assemble without soldering to create the mechanism. Not everybody has a soldering iron. ;)

Snellingkorey2 months ago

very, very good, usless it might be, amusing definately!

jmengel2 months ago

Just saw this. You've officially "made it" when your ideas are being knocked off overseas....

davidbarcomb4 months ago

This is interesting. I will try this out

Equus1 year ago
Hi, my servo is going only "forward" until it's stopped by mechanic lock. I dont know what is wrong. And sorry for my english.
GokalpC Equus5 months ago

Hi, I just built one from the schematics as well and it does the exact same thing as yours: wherever the switch is it keeps on going on one direction and on one side of the switch if you press the button it stops. so did you find the solution ?

MicioGatta6 months ago


Kite builder10 months ago

Not really useless.

It can be used as e Cat-Toy.

but add a small, but noticeable wooden plate to the small lever-switch, then the cat can better punch it to activate the box.

in this video at 2.07 a cat plays with something like this:

in that version the arm and the area around it are covered by plush.

That looks like a small kitten in the box

Halphinian11 months ago

What are the advantages of the dead bug?

Kelly021 year ago
I want to try to make this!!

Same here!

We simplify a circuit in the machine. Only a switch with two points is used. No chip, no servo, no spring and no additional switch are used. The movie below shows its structure and action.
bdimapasoc2 years ago
Newbie question: Why are there no resistors in the wiring (referring to the design which doesn't use the 555 timer)? Are the internal resistances of the servo, batteries, switch, and wires enough to prevent an overly large amount of current from running through the circuit?

If that's the case, then is there a way to get the numerical values for these internal resistances?
You are correct. If wired correctly it is limited mostly to the resistance in motor, and it's only a few ohms (it will vary from motor to motor, but lets say 5-6 ohms).

Ideally, the switches and wire should have no resistance, but in the real world they will add a tiny bit too.

The battery, you don't worry about it's internal resistance.

To measure the actual resistance, take the batteries out and measure the ohms across the + & - of the battery-holder.

So if the whole circuit is 6 ohms and you're using 3 volts, that's half an amp of current. Extra points if you can figure out how many watts that is!
surfcurve3 years ago
Just finished mine and it was a little more difficult than i thought it would be, but worth it. I used krazy glue to hold everything in place. If anyone has an issue with your servo not being strong enough to flick the switch like it did, U can take switch apart and change out the spring in the middle of the switch ( i used a pen spring instead of original spring inside of the switch and it works flawlessly now.) I went with the simple method with the 2 switches and a cigar box which already came with a center cut in the lid. Will now make a great conversation piece on coffee table. Good luck to everyone who tries to build one!!! Well worth the few hours of effort.
useless machine.jpguseless machine2.jpg
Thanks for this. I had to do the same thing. Works great.
Right on. Sometimes you can 'break in' a stiff toggle just be flipping it on/off a bunch of times but replacing the spring, that's a new one!

hohohe1 year ago
Built a couple of machines using solarbotics Gm2 motor, toggle and micro switch. They work fine, but they shatter one time when hitting micro. Any idea on what is really happening. Motor does have a little play
Chloe81 year ago
This is so cute! there must be some ways to use them.
What's the name of that song on the video?
Wow! This is great! Thank you so much!
Hi can you provide me the Circuit diagram and the PCB drawing as well as the ttemplates of the Ultimate machine please. I wish to make this for a school project but i need this infomation.
Aaron10882 years ago
Hi I made a useless machine (the version in step 5) and I have a problem of the arm jumping on the off microswitch. basicly when it goes back in it hits the off microswitch and jumps up and down and up and down. It is not ment to do this and I dunno how to solve it. I know the micro switch is working to turn it off becuase if I press it by hand it works. any ideas?
The bounce-back problem can be eliminated by moving the micro-switch to a spot were the arm doesn't slam into it.

The Ultimate Useless Machine that I sell uses a 'cam' to activate the micro:

Check the above photo to see how it's arranged. Instead of the arm crashing into the micro, the bump on the cam activates the micro and allows the motor to continue moving a few degrees before coming to rest.
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