loading

Step 2: How Does It Work?

Inside the box is an geared motor powered by double A batteries and two switches: a toggle switch on the top of the box and a micro-switch inside. That's it.

The switches are positioned to be limit switches for the motorized arm. The toggle causes the motor to reverse, while a micro-switch powers down the circuit when the arm finishes retracting back into the box.

When idle, the circuitry is fully powered down. The toggle is “Reverse” direction, and the micro-switch is being held in the off position by the servo arm.

Keep in mind the micro-switch is wired up so that it works completely opposite from a normal switch like you would find in a doorbell. By using the common pin and the normally closed pin the micro switch is “OFF” when it’s button is being pushed.

When a person turns the toggle switch to the forward position, it also provides power to the motor causing it to rotate the arm towards the toggle switch.

As the arm moves away from it's off position it releases the micro-switch providing the backup power needed for the motor to retract after the toggle switch is turned off.

When the toggle gets switched “OFF” it actually reverses the motor’s direction. The arm reverses direction returning towards it's 'OFF' position. When the arm runs into the micro-switch it stops.

The toggle switch needed is a Dual Pole, Dual Throw (DPDT) toggle switch. This type of switch is actually a pair of switches which operate together (Dual Pole) and both are On-On (Dual Throw).

<p>Here's the one I built:</p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/MUWtEr7Ee9A" width="500"></iframe></p>
<p>I've seen videos of this machine many times before. Well, it might be useless, but it's still plenty of fun.</p>
<p>Here is mine!</p>
<p>The case looks sweet, box joints it looks like. Did you make the box from scratch? </p>
Thank you! Yeah these are box joints. Everything is from scratch, but carpentry is my big hobby so it was an easy challenge.
<p>Thanks for posting the pic!</p><p>I've been slowly learning to work with wood, and starting to get better. Much more satisfied with the results compared to building things with acrylic. &quot;Back to nature&quot; I guess is what is happening with me. </p>
<p>I made this for a &quot;evil Santa&quot; gift at a family get together. It was a big hit. Thanks for the instructable! </p>
<p>My pleasure, tbillingsby!</p>
<p> I just recently saw one of this with a row of switches and the arm would go and switch them all off in the exact same order before settling down. </p>
<p>The &quot;troll machine&quot; sounds like a pretty good name for this device. I think it would make a great prank present for a close friend.</p>
I found something similar. Make sure you watch until the end.<br> <object style="height: 390.0px;width: 640.0px;"><param name="movie" value="http://www.youtube.com/v/UmQ5LsNMXZ4?version=3"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"></object><object style="height: 390.0px;width: 640.0px;"><param name="movie" value="http://www.youtube.com/v/UmQ5LsNMXZ4?version=3"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed allowfullscreen="true" allowscriptaccess="always" height="390" src="http://www.youtube.com/v/UmQ5LsNMXZ4?version=3" type="application/x-shockwave-flash" width="640"></embed></object>
<p>Ok, that's an awesome mod!</p>
<p>This one is cooler XD</p>
<p>what happened there, AI!!!!!!!+ wheels.</p>
it's the useless-inator... i thought doofenshmirtz gave up.<br>ah well...
LOLOLOLOL
get the sledgehammer<br>
haha saw this a couple months ago, still funny!
dude this thing is sico!!!
RAGE!!!!!!
nice video<br>
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<br><br>Thanks for the nightmare :)
lol
<p>Here's an animated schematic of the switch-only version (without crossed wires!!!) that explains how it works:</p>
<p>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. </p>
<p>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. ;)</p><p><a href="https://www.kickstarter.com/projects/67279121/useless-machine-in-a-can-fun-kit-for-everyone" rel="nofollow">https://www.kickstarter.com/projects/67279121/useless-machine-in-a-can-fun-kit-for-everyone</a></p>
<p>very, very good, usless it might be, amusing definately!</p>
<p>Just saw this. You've officially &quot;made it&quot; when your ideas are being knocked off overseas....</p><p>http://www.dx.com/p/neje-wooden-useless-fully-assembled-machine-box-toy-w-logo-brown-2-x-aa-365899#.VKtghyvF98E</p>
<p>This is interesting. I will try this out</p>
Hi, my servo is going only &quot;forward&quot; until it's stopped by mechanic lock. I dont know what is wrong. And sorry for my english.
<p>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 ?</p>
<p>LOL!</p>
<p>Not really useless.</p><p>It can be used as e Cat-Toy.</p><p>but add a small, but noticeable wooden plate to the small lever-switch, then the cat can better punch it to activate the box.</p><p>in this video at 2.07 a cat plays with something like this:</p><p><br><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/PEykiwFg39k" width="500"></iframe></p><p>in that version the arm and the area around it are covered by plush.</p><p>That looks like a small kitten in the box</p>
<p>What are the advantages of the dead bug?</p>
I want to try to make this!!
<p>Same here!</p>
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. <br>http://youtu.be/3Pl0nNj8Q4s <br>
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? <br> <br>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). <br> <br>Ideally, the switches and wire should have no resistance, but in the real world they will add a tiny bit too. <br> <br>The battery, you don't worry about it's internal resistance. <br> <br>To measure the actual resistance, take the batteries out and measure the ohms across the + &amp; - of the battery-holder. <br> <br>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!
P=IV=.5(3)=1.5W
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.
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!<br><br>Thanks!
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

About This Instructable

1,502,409 views

1,686 favorites

License:

Bio: Frivolous Engineering is the end result of a hobby that got out of hand.
More by Frivolous Engineering: The Turn-Me-Over Stone The Most Useless Machine EVER! Recumbent Bike
Add instructable to: