Useless^2 (The More Pocket Sized Way.)




About: I love building things and taking pictures.
I'm sure most people have heard of the most useless machine. When it is useless x useless he calls it useless squared. I built a simpler useless squared that does't use a DPDT switch nor does it use two motors. The video will explain.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Get the Parts

You will need:
2 555 timers (You only need one but get two just in case you break one.)
Jumper Wires/ Component Leads
1Kohm resistor
4.7Kohm resistor
10Kohm resistor
33Kohm resistor
68Kohm resistor
0.01uF capacitor
0.1uF capacitor
General Purpose NPN transistor (don't use a power requires more power to operate.) (2N3904,BC547, etc.)
Servo Motor (DON' T use a micro torque...) (Use a continuous rotation servo if not...mod a regular servo.)
Batteries and accompanying holders
SPDT Slide Switch (don't use rocker or toggle)

Step 2: Build the Circuit.

Build according to the schematic except...with the two buttons use the switch. The middle lead or common, is pin 6 of the 555 and the other two are the 68K and the 10K resistors. For the Servo leads, connect component leads (cut) to the servo's female headers. You could use male headers but that is harder to solder. Then plug them into the board.

Get the accompanying horns that come with the servo and pick the one with TWO arms.

Unscrew the old horn and replace the new one...if you already have it in well then...GREAT!

Once the switch is soldered and the motor is mounted test it out... if it starts rotating one way then flip the switch...if it works...


Now hot glue the slide switch to the motor. Make sure that if its going on the right side of the servo with the horn on its left the 68Kohm resistor is closest to the end of the servo.

If its on the left follow the exact opposite.


Step 3: Play.

Congratulations...and, not so congratulations. If you made it to this step it may mean that you have successfully made this product. It may also might mean that for those of you who didn't build this this project and just read it you don't have a working product.



As always...if you experience any problems leave a comment and I will try my best to help you.

If you did make it successfully well then...leave a comment saying you made it successfully!

Step 4: Solder.

I don't normally add steps to my ibles but this one is different. 

After soldering and professionalizing, heres what I got: (pictures above.)

Pocket-Sized Contest

Participated in the
Pocket-Sized Contest

4th Epilog Challenge

Participated in the
4th Epilog Challenge

Hack It! Challenge

Participated in the
Hack It! Challenge

The Mad Science Fair

Participated in the
The Mad Science Fair

Be the First to Share


    • Book Character Costume Challenge

      Book Character Costume Challenge
    • Made with Math Contest

      Made with Math Contest
    • Cardboard Speed Challenge

      Cardboard Speed Challenge

    13 Discussions

    let me get this straight, the servo tester is just an H-bridge right?
    i want to make this using a flipflop, can i use the one you showed in your other instructable about the 555 timer or a 556 dual timer?

    Ahhh...I said H-bridge in the video...

    The servo has a board inside of it that reads pulses It is basically an H-bridge INSIDE the servo.

    No...the 555 sends a pulse to the servo. This is probably the best tester if you don't want to take apart your servo. You don't have to mount the switch on the side. I'll research the idea, however.

    oh, i get it now, i didnt knew the difference between a regular motor and a servo but i read a little bit of theory on it, i would like a little bit more information on the 555 timer flipflops tough

    Bistable is a flip-flop. Basically, it will remain in one position until it is reset.

    Trigger from pin 2 will cause it to set high. Pin 4 will reset the flip-flop when it is pressed.

    Any questions?

    Class dismissed.


    7 years ago on Introduction

    Very good! I like it!
    Did you try a single servo horn? ...that would give a full 360 rotation, and a little slower action.

    This could be used to power "window" wipers on a pair of steampunk goggles, or drive an antenna sticking out the top of a hat! ...still very useless, of course, but with a slight oscillation of whimsy!

    Hope you win the robot contest!

    2 replies

    This line says that it is a very clever idea. By the way ,I have no idea why it got cut off.

    Thanks for the encouragement.

    I know what you mean. I had thought of this but I didn't want to mod the servo. It was not cheap. I could have bought another servo but I didn't have enough time for the robot challenge.