Balancing Robot




About: I'm a mechanical engineer, and I like computer programming, mechanics, electronics and specially the robotics.
This is a very simple robot that uses a simple switch as a sensor and stands on only two wheels with inverted pendulum mechanism.
When the robot is going to fall the motor starts and moves the robot to the direction it is going to fall, so the motor torque about the center of gravity that is higher than the motor makes the robot balanced.

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Step 1: Things You Need

To make this robot you need following parts and tools:
small electric motor
some gears
(or a motor with gearbox)
a shaft
two wheels
some sheets of plastic to make bearings and the robot neck
two battery holders
4 AA batteries
one button cell
one SPDT (single pole double throw) switch with a metal lever
one toggle switch for the on/off switchs
one nail
some wire
soldering iron
some glue

Step 2: Motor, Grears, Shaft, and Wheels

In this step you must make a system to moves the robot you can make it easily by adding some gears to a simple small motor, then connect it to a shaft and assemble it two wheels.
You can also use a motor and gearbox.
It does not matter how you make it.

Step 3: Attach Robot Neck and Head

Use glue to attach a sheet of plastic to the motor.
Then put some glue on one side of battery holders and attach them to the top of the plastic sheet.

Step 4: Making the Sensor

Solder a button cell to the SPDT switch lever.
Make the nail head hot on a flame and put it on the plastic sheet on the motor in a position that when the robot stands vertically the button cell touches the ground.
Then attach the switch to the robot with glue.

Step 5: Connecting the Switch

Solder a wire form positive pole of one of battery holders to the negative pole of the other battery holder and attach the toggle switch to it.
Then attach the other side of the switch to the motor.

Step 6: Wiring

Now it is time to solder the robot wires.
Note that you must solder the wires in a way that robot moves to the direction that is going to fall.

Step 7: Testing

The robot is now completed and it is time to test it.
Put 4 batteries into the battery holders and turn on the switch.
Try to change the position of the sensor to make the robot works better.
If the robot works inverted swap the red and blue wires on the sensor or on the battery holders.

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    237 Discussions


    1 year ago

    waw with a nothing you amaze us.


    1 year ago

    waw avec un rien vous nous épatez.


    3 years ago

    Assalamu alaikum, I decided to ask you about the wire connection, would you like to giving a picture of it ?

    1 reply

    4 years ago

    This is VERY VERY WITTY. Very simple way to create a self balancing robot.

    I saw... I could say, the opposite robot, a very stable two wheels robot here (it is open source): This robot uses stepper motors instead.


    Reply 4 years ago

    You can buy a switch with lever or find some without lever in a dead computer mouse and attach it a lever.


    4 years ago

    best use of brain


    5 years ago on Introduction

    The easiest Arduino UNO based self-balancing robot, controllable by Smart Phone, RC and more!


    10 years ago on Introduction

    The problem isn't the center of gravity, it's stability. The switch will work as a measurement device so long as the robot is VERY close to vertical. If you get much past that narrow threshold, the robot doesn't add more torque to the motor to compensate. If you want it to be more stable, you'll have to use some analog device to measure the tilt-angle and another circuit to control motor torque through input voltage. A simple sensor would be a multi-turn potentiometer.

    2 replies

    Reply 5 years ago on Introduction

    Another possibility for variable torque control, more in the spirit of the author's design, would be to add two additional switches (one for each possible direction of fall), arranged to turn on only when the robot gets closer to the horizontal on that side. Each of these switches would add an additional battery into the circuit in series. Then the robot would be carrying six or even eight batteries. As a bonus, the additional weight of the batteries might actually help it work more smoothly.


    Reply 10 years ago on Introduction

    You're right.

    High CG object has high moment of inertia, so it needs more moment to move and has more stabillity. Because of these you must choose the longest robot and consider your motor power.

    The more complex controlling system, the more stabillity. but the most important feature of this robot is that it is simple (according to the the others comments)


    5 years ago on Introduction

    This is a wonderful, excellent project. The approach is exactly what one wants from a first build of any new device: the simplest possible implementation, with the loosest possible tolerances and the most room for experimentation to make the device work, and then to improve it.


    6 years ago on Introduction

    good day buddy! can I use this experiment for our science investigatory project? please, I'll give a credit in return. Please :/

    1 reply

    6 years ago on Step 6

    why is the switch in between the battery packs instead of after?