This project is from Gen Alpha Episode 2 on Ahasa TV. Watch the episode to see the Snailbot fold, wire up and crawl, then follow the steps below to build your own!

Print the Snailbot template on card or thick paper. The key shows you what each line means:

• Solid red line: cut
• Green dotted line: valley fold (fold up, towards you)
• Blue dotted line: mountain fold (fold down, away from you)

Arrows that meet mean valley, and arrows that point apart mean mountain.

Template design: Tanvi Pati, UCLA LEMUR lab.

Cut along the solid red line. Then punch out the two small circles with the tip of a pen. Put the cut-out flat on the table, printed side up.

Fold the boxes in number order:

1. Box 1: fold the two curved green lines up (valley folds).
2. Box 2: pick it up and fold the blue lines down (mountain folds).
3. Boxes 3 and 4: carry on the same way. Green goes up, blue goes down.

Press each crease firmly with your fingernail.

Squeeze and release the two side flaps, and your Snailbot crawls! To drive it with a string, thread it through both holes, loop it back through in the same order, and knot the ends. Pull and release to make it move. Right now, you are the robot's brain!

A robot is like a body:

• Brain: the Obo Play board (an ESP32 microcontroller)
• Muscle: the servo motor
• Nerves: the wires
• Energy: the battery or USB power
• Thoughts: the code

Next we give our Snailbot a brain and a muscle.

The Obo Play is a tiny computer, smaller than a biscuit. It has an ESP32 chip with Wi-Fi and Bluetooth, and it runs the code we write.

The SG90 servo is the muscle. It doesn't just spin. It turns its arm to the exact angle the brain asks for, anywhere from 0° to 180°.

The servo has three wires. Connect them to the Obo Play:

• Brown (ground) → GND
• Red (power) → 5V
• Orange (message) → GPIO 13

Red brings power, brown is ground, and orange carries the messages from the brain.

Tape the servo onto the Snailbot's back. Tie the string from Step 5 to the servo's arm, so when the arm turns it pulls the snail's body, and when it turns back it lets go.

A program is a list of steps that the brain follows again and again:

1. Turn slowly to 130°, which stretches the body forward.
2. Turn fast back to 50°, which pulls the back up.
3. Repeat!

In the Arduino IDE, install the ESP32Servo library (Tools → Manage Libraries), then upload this code:

#include <ESP32Servo.h>

Servo servo;

void setup() {
  servo.attach(13);              // orange wire on GPIO 13
}

void loop() {
  for (int a = 50; a <= 130; a++) {   // slow stretch
    servo.write(a);
    delay(15);
  }
  for (int a = 130; a >= 50; a--) {   // fast scoot
    servo.write(a);
    delay(4);
  }
}

Put your Snailbot on the table and power it up. Slowly to 130° stretches it, and fast back to 50° makes it scoot. Stretch, scoot, repeat. That's how Snailbot crawls!

Challenge: change delay(15) to delay(8). Is your snail faster? What happens if it goes back slowly too?

The brain sends an angle, the wire carries the message, the servo turns to that angle, and the snail crawls. That's how a robot moves! Try folding a second Snailbot and race them.

Now it's your turn to build a Snailbot:

1. Fold your Snailbot from the template.
2. Wire the SG90 servo to the Obo Play (orange wire on GPIO 13).
3. Upload the code.
4. Film it crawling across the table.

Then submit your build: click I built this at the top of this project and add a photo or short video of your crawling Snailbot so everyone can see it.

Bonus challenge: make your snail faster, or fold a second one and race them. Tell us your best time in your build!