Few robots are more recognisable than WALL·E; his cute appearance and distinctive personality make him instantly endearing to anyone who sees him! In this project, I designed a WALL·E replica with the aim to allow each of the robot’s joints to be moveable by hand or using servo motors.
Loosely based on the dimensions and design of ChaosCoreTech’s Wall-E replica, this version was designed from scratch in Solidworks and allows 7 of the joints to be actuated, including the arms, neck, head and eyes. The robot design has the following features:
- Each eye can be raised and lowered independently with servo motors.
- There is room in each eye to add a small camera.
- The head can look left and right using a servo motor.
- The neck is actuated at two joints, allowing the head to look up/down and to be raised/lowered.
- Each arm has a motor at the shoulder to move it up/down.
- The arms consist of pressure fit joints, hands and fingers, which can be manually posed.
- The tank treads (skid steering) are fully 3D printed and can be powered using two 12V DC geared motors.
This is an ambitious project, aimed at people who want to build a fully animatronic WALL·E robot with servo controlled joints. It took me about 3 months to design and assemble the robot, with more than a month spent on just 3D printing all of the parts. In total, there are 310 parts (although 210 of those are very small and make up the tank treads).
List of 3D Printed Parts
The robot comprises of 310 individual parts, so this definitely is not an easy project suitable for people who don’t have much experience with 3D printing! Personally, I spent more than a month printing all the parts, with the printer running almost every day. The largest components (the main body parts) took up to 14 hours of print time each, while the smaller parts took 5-6 hours. If you are interested in making your own robot, I have uploaded the 3D files for all the components on Thingiverse.
List of other Components
A variety of other hardware is used to fasten the 3D printed parts together and bring the robot to life. A list of the hardware and electronic parts that I used is shown below. To make WALL·E look more realistic, I took apart some old binoculars and used the lenses as the eyes. I think that the shine and reflections on the glass adds a lot of soul to the robot, and make him look even cuter.
- M3 Bolt, 10mm length – x14
- M3 Bolt, 20mm length – x12
- M3 Nut – x26
- Paper clip (used for linkages) – x2
- Binocular lenses (for the eyes) – x2
- 9g Micro Servo Motor – x7
- 12V DC Geared Motor (60RPM) – x2
- Arduino Uno (or equivalent) – x1
- Motor Controller Shield – x1
- i2c Servo Controller Board – x1
- 12V DC Battery Pack – x1
Note: Links are for reference only, and are not where I bought my parts. Please shop around to find the best supplier near you!
While it is possible to use a Wifi/bluetooth connected Arduino micro-controller to control the robot, I decided to use a Raspberry Pi instead. Since the Raspberry Pi is essentially a small computer, it can be used to play sound effects, stream the video from a USB camera, and host a web interface through which the robot can be controlled.
3D Design and Printing
I designed all the components in Solidworks, using images and other 3D models as reference. The main aim in the design process was to split the robot into small enough pieces so that they would fit into the 3D printer, and also to integrate all the motors and electronic components. I tried to make the robot as small as possible, while still leaving enough room for the motors.
After 3D printing each of the parts, I spent a lot of time sanding the parts to remove all of the print lines and give them a smooth finish. Two coats of filler-primer were then applied, with more sanding done between each of the coats. Using a primer is important, as it helps the paint to stick to the plastic and not rub off as easily. It is also useful as it makes imperfections and bumps on the part more obvious, showing where further sanding needs to be done.
Each of the parts was then individually painted with lacquer spray paints. I only used yellow, white, light grey, dark grey, black, and red spray paints to paint the whole robot. By splattering light layers of black and red paint onto the parts that were painted grey, it was possible to add texture and make them look a lot more like real metal.
Finally, after fully assembling the robot, I used black and brown acrylic paints to weather the robot. This involves applying the paint liberally onto all the surfaces, and roughly wiping away most of it with a towel. The paint that isn’t wiped away stays in the corners and crevices of the parts, making the overall replica look older and more realistic.
The video below shows how to assemble the robot. Overall, the assembly is not too difficult, but it is important to put the parts together in the right order. While a couple of small parts needs to be glued together, most parts are fastened together using bolts. This makes assembly and disassembly easy if any parts need to be fixed or replaced. The trickiest part was probably the wiring, figuring out how to connect the motors in the eyes of the robot to the controller in the body.
Wiring and Electronics
The wiring diagram is shown below, illustrating how each of the electronic components were connected in the robot. The USB port of the Arduino Uno was then connected to the USB port of the Raspberry Pi. If the 12v to 5v DC buck converter is capable of delivering up to 5 amps, then the Raspberry Pi can be directly powered from the converter. Otherwise, it should be connected to a separate 5v battery.
The programming of the robot can be split into two main parts; the code for the Arduino micro-controller, and the web-server on the Raspberry Pi. I’ve uploaded all my code onto GitHub; the link is shown below.
The Arduino controls all of the motors within the robot, determining how they should move. In the code I added a velocity controller, so that the servo motors don’t suddenly jump into life at full speed, but instead start and stop gently.
The Raspberry Pi is connected to the Arduino via a USB cable, and can send user commands to the Arduino to make the robot move in a specific way. The Pi is also connected to a USB webcam and a speaker, and can play sound effects. The code is written in Python, and uses ‘Flask’ to generate a webserver. Any computer on the same local network can then access the page and remote control the robot.