Here is an inspiration for you on how to make a soft robot in less than an hour!

Okay, it is not exactly soft you will argue, but it has some soft parts - the glue sticks! Not only they are soft, but they have a very important feature - they form the body of the robot and they act as springs. It is important to realise that their springy quality is used to drive the robot forward.

The robot is able to move because its tail has very little friction with the ground when moves in one direction and very high friction on the opposite direction. The tail is simply pulled forwards by the two ropes. Then they release, the springy quality of the glue sticks pushes the front forwards while the tail is stuck to the ground.

Check the video and you will see what I mean.

Step 1: Stuff You Need

The list is very simple:

Some thin nylon rope
Hot glue and sticks
Servo
Arduino (Uno or Mini or any other microcontroller that can drive a servo)
Battery

Step 2: Hardware Assembly and Software

Connect your servo to the microcontroller and power supply. I used two servos to give me more power on the ropes, but it is up to you and the actual servos you find. Then program the microcontroller to swing the servo backwards and forwards. Check the code attached.

Finally, put your robot together! Stick the servo in a box and feed the rope through it. Stick a glue stick to the box and bend it. Tie the end of the rope to the free stick end and that is it! Use my diagram as a reference, but feel free to experiment on your own. There are infinite number of solutions. Share them in your comments below.

The boxes that house the microcontroller, battery and the servo are 3D printed - not the cheapest way but it looks neat!

Robot.ino
Download

Step 3: Testing on Different Sirfaces

It is able to crawl over artificial grass, smooth plastic and rough terrain. I had to add spikes to the tail to make the friction greater on the grass terrain.