Angle Controllable Seesaw

by gchari in Circuits > Arduino

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Angle Controllable Seesaw

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This project is an angle controllable seesaw that is intended to demonstrate feedback controls. There is a seesaw structure with a DC motor with a propeller on one end of the arm. This motor spins to generate a force on the seesaw arm to keep it horizonal. The angle of the arm is detected indirectly by using an ultrasonic sensor. This sensor measures the distance from the ground to the motor. If this distance is smaller than nominal for a horizonal arm, then the motor spins faster to lift the arm up more. If the distance is larger than nominal, then the motor decreases its speed. The motor’s speed is computed by the Arduino using a PID controller. There are two status LEDs. The green LED turn on when the motor is spinning, and the red LED turn on when the motor is not spinning. There is also a switch to turn the red LED off. I found that the motor does not spin fast enough to generate large amounts of thrust, so for the motor to have the desired control authority, the seesaw should be reasonably close to balanced, which is why the 9V and AA batteries are on the other side of the arm. The 9V battery powers the motor, but the AA battery is just there for balance.

Supplies

Propeller

Ultrasonic Sensor

Cardboard

Pen

9V Battery

DC Motor

H-Bridge

AA Battery

Resistors

Masking Tape

SPDT Switch

Arduino Uno

Breadboard

LED

Jumper Wire

Draw Two Lines to Divide a 5”x7” Piece of Cardboard Into Three Parts

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Fold Along the Lines Into a U Shape and Stick a Pen (or Any Other Axle-like Object) Through the Cardboard About Half an Inch From the Top

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Mark and Cut Off a 1.5”x7” Piece of Cardboard to Make the Arm

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Glue Another Small Rectangle of Cardboard Onto the Arm to Give the Ultrasonic Sensor More Surface Area to Detect and Bore a Hole Into the Two Layered Pieces Big Enough to Press Fit the Motor Onto the Arm

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Press the Motor Into This Hole

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Glue the Arm Onto the Pen

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Glue a Cardboard Stiffener Onto the Structure to Keep It in a Rigid Box Shape

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Tape the Ultrasonic Sensor Underneath the Motor Side of the Arm

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Tape on the 9V and AA Battery Onto the Other Side of the Arm

Build Circuit According to Schematic

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Project Report

Arduino Code

Downloads