Acrobatic Stunt Robot - Acrobot

The aim for this project was to recreate a technology used in the live entertainment industry. The stunt-capable robot, designed by Disney for their Disneyland parks, mimics Spider-Man swinging over the Avengers Campus. This technology peaked our interest. Our team chose to create a scale model of the prototype used to demonstrate this technology - "stickman." This Instructable is intended for beginners and will guide you to build a working model of stickman from inexpensive, off-the-shelf parts using only a utility knife, pliers, a drill, and hot glue gun.

Materials:

Electrical:

• Arduino Micro microcontroler
• Breadboard
• Jumping wires
• Potentiometer
• L293D motor driver IC
• DC air pump (Mitsumi R-14 A213 370 DC 6V)
• AA battery pack capable of holding 4 AA batteries
• 4x AA batteries

Mechanical:

• 2x 20 mL syringes
• 20" of flexible tubing (ID/OD 0.17/0.25")
• 2x T-connectors
• ON/OFF valve
• ~30x popsicle sticks
• Long, thin rubber band
• Large paperclip

Tools:

• Utility knife
• Pliers
• Drill with a 1/16" bit
• Hot glue gun
• Computer to program the Arduino
• USB cable to connect the Arduino to the computer

If not already installed, follow this Instructable to install the Arduino IDE on Windows 10. Connect your Arduino board to your computer using the USB cable. In the Arduino IDE, select the correct board type and COM port.

Follow the provided Fritzing diagram to assemble the electrical system. Copy the attached code from below and paste it into the Arduino IDE. Compile and upload the program to the Arduino. Turn the potentiometer to control the speed of the air pump.

Bishop, Hayden Scott12:43 PM

int pwmPin = 12; // assigns pin 12 to variable pwm
int pot = A0; // assigns analog input A0 to variable pot
int pwm_signal = 0; // declares variable c1
int pot_read= 0; // declares variable c2





void setup() // setup loop
{
pinMode(pwmPin, OUTPUT); //assign pin 12 as output
pinMode(pot, INPUT); //assign pot pin as input
}




void loop()
{
pot_read= analogRead(pot); //reads ADC (analog) value to pot_read for "off" portion of waveform
pwm_signal= 1024-pot_read; //max ADC value is 1024, so the "on" portion is max-adc read
digitalWrite(pwmPin, HIGH); //output on for the selected "on" time
delayMicroseconds(pwm_signal);
digitalWrite(pwmPin, LOW); //turn off output for "off" time
delayMicroseconds(pot_read);
//the rapid on and off of the output produces a square wave called PWM, pulse width modulation
//the longer the square wave is on, the faster the IC driver runs
}

Glue together 4 popsicle sticks at the corners to form a square. Glue a 5th pipsicle stick across the middle of the square to divide it into 4 square holes. Pick one of 4 square holes and insert a syringe into it. Angle they syringes in towards the middle of the square base. The body of the syringe should make contact with the borders of it's square hole in at least 2 places. Ensure the syringes is fully inserted - as shown in the picture above. Use hot glue to secure all contact points. Repeat this procedure with the second syringe in the opposing corner. Next, cut 3 popsicle sticks in half. Glue 3 halves together in a stack. Create two stacks and drill a hole through one end of each of them. Repeat this procedure to create 4 stacks in total. Pick one of the remaining square holes not occupied by a syringe. Glue 2 stacks on their side along the edges of the square hole. The stacks should be parallel to each other and its respective syringe. The end of each stack with the hole drilled through it should face away its respective syringe. The holes of both stacks should be aligned with each other across the square hole. Repeat this procedure for the final square hole.

Make the 2 legs by laying 2 pipsicle sicks end-to-end on a flat surface. Place hot glue along the length of a third popsicle stick and center it above where the ends of the first two Popsicle sticks meet. Place it down, pressing it firmly with your fingers. Before the glue dries, rotate the assembly 90 degrees and firmly press all edges against a flat surface to ensure the leg is straight. Cut a fourth popsicle stick in half and use it to fill in the remaining space on both ends of the leg. Glue 2 more popsicle sticks along the top of the assembly. Again, rotating the assembly 90 degrees and firmly pressing all edges against a flat surface to ensure the leg is straight. Finish the leg by drilling a small hole through one of it's ends. Repeat this procedure to construct the second leg.

Bend the large paperclip as straight as possible. Pick one of the two square holes with stacks glued along its edges. Insert one end of the paper clip through the hole drilled into the end of one of the two stacks. Pick up one of the 2 legs and align the hole drilled into its end with the paperclip. Push the paperclip through the leg, continuing to push through the second stack. Use the pliers to bend a small stop at the end of the paperclip. Use the pliers to cut the excess paperclip. Bend another stop into the remaining end of the paperclip to secure the leg. Repeat this procedure to secure the second leg.

Cut a popsicle stick into quarters. Glue 2 quarters into a V shape. Glue the remaining 2 edges of the V to the top of a syringe plunger to form a pivot at the top of the plunger. Insert the plunger into one of the syringes. Cut the large, thin rubber band into 2 pieces. Thread one piece of the rubber band around one of the legs and through the V. Tie the piece of rubber band at both ends to hold the pivot against the leg. Repeat this procedure to secure the second leg.

When designing the pneumatic circuit for this project, we took inspiration from this soft robotics project created by Jonas Jørgensen.

Follow the provided schematic to assemble to pneumatic circuit. Cut the 20" of flexible tube into, two 6", one 4", and two 2" pieces. Begin by pressing the first 2" piece onto the pump. Use hot glue to secure the pump firmly onto the underside of the chassis below either of the leg joints. Connect the first T-connector to the other end of the first 2" piece. Add one 4" and one 6" piece to the remaining outlets of the first T-connector. Press the other end of first 6" length onto the end of the first 20 mL syringe. Connect the second T-connector to the other end of the 4" piece. Connect the remaining 2" and 4" pieces to the remaining outlets of the second T-connector. Connect the ON/OFF valve to the other end of the second 2" piece. Connect the second syringe to the other end of the second 6" piece.

Congratulations! You've just made your own model of a acrobatic stunt robot! And if anybody asks, you can proudly say that you made it yourself! Here is a demo video of our Acrobot in action for reference.

Go Ballistic!