Introduction:

The Raspberry Pi is a credit card sized single board computer that can be used for many of the things that the average desktop computer does such as spreadsheets, word-processing, games and playing high-definition video. Beside functioning as a desktop computer, Raspberry Pi is also being used by many people all over the world to learn programming, electronics, robotics and etc.

Here, we present our Raspberry Pi 8 DOF Wi-Fi quadruped robot. The robot is featured video vision streaming and Wi-Fi control via neat and simple web interface. We release all information to people to build it by themselves.  Raspberry Pi version from 1A+/1B+ to 3 and Zero/Zero W can be used to build this robot.

Below figures shows an implemented using  RPi B+ and camera module V1.3.

 

 

 

 

 

  

Components:

To build one, you will need following items. The electronic components can be found in online store such as taoboa, amazon, aliexpress and etc.

  1. Raspberry Pi 1A+, 1B+, 2, 3
  2. Nano size  WiFi USB dongle or equivalnet for 1A+,1B+, 2 & Zero
  3. Raspberry Camera V1.3,  optional if no vision video streaming
  4. Raspberry Pi I/O Expansion Board
  5. 3D printed STL model files, download here.
  6. Robot System SD card image: The image is based on LEDE project.  The user guide is applicable to the robot for other system setting.  You see the section Preparing the SD Card for how to write the image to SD card. Any SD cards that size is bigger than 256MB can be used since the size of image file is less than 256MB. There are 3 SD images respective to different version of Raspberry Pi, download at below.
    1. SD image for Raspberry PI 1
    2. SD Image for Raspberry Pi 2
    3. SD image for Raspberry Pi 3
  7. 8 servo motors  - Tower Pro MG996R or compatible
  8. 3.7V 18650 battery pack - two 18650 batteries in parallel

Prior to build or assemble the robot, you need to 3D-print the models and preparing the SD card for Raspberry Pi.

 

3D Printing the Models:

Those implementations in demo were printed in PLA.  The models were sliced using Cura.  Here are the suggested parameters for slicing the robot models to print. You may adjust to fit the 3D printer you're using. 

  • layer height: 0.2mm
  • shell thickness: 1mm
  • bottom/top thickness: 1.2mm
  • support: needed
  • adhesion type: none
  • fill density: 10%

 

Preparing the SD card:

Installation of System Image 

You will need to use an image writing tool to write the image onto your micro SD card.

Etcher is a graphical SD card writing tool that works on Mac OS, Linux and Windows, and is the easiest option for most users. Etcher also supports writing images directly from the zip file, without any unzipping required. To write your image with Etcher:

  • Download Etcher image writer
  • Connect an SD card reader with the SD card inside.
  • Open Etcher and select the image file you wish to write to the SD card.
  • Select the SD card you wish to write image to.
  • Review your selections and click 'Flash!' to begin writing data to the SD card.

Testing SD Card and WiFi Setup

After you install the system image to the SD card, next step is to setup the Wi-Fi connection. 

  • Connect your computer to the LAN port of Raspberry Pi
  • Optionally, connect the Raspberry Pi to a HDMI monitor for booting messages
  • Connect the USB Wi-Fi dongle to USB port if not RPI3
  • Insert the SD card to Rapberry Pi,
  • Power on RPi to boot, the green LED will be flashing for few seconds.
  • After boot up, the Raspberry Pi becomes a Internet and WiFi router, it will allocate IP address in range of 192.168.1.0/24 to any network devices connected to it via LAN port or WiFi.

In your computer, open a web browser, access the http://192.168.1.1/ You should see system administration page as below figure. Clicking Login, initially there is not password. Following sequence figures, you can complete the WiFi network setup.

 

 

 

 

 

 

  raspberry-pi-3d-printed-8-dof-quadruped-robot

 Now, you should have the robot WiFi ready. 

 

Robot Assembly:

You must have 3D printed models and the SD card ready. If you have those ready, watch assembling video at below.

 

 

 

 

How To Play:

Firstly is to join the robot WiFi network. Initially the SSID is LEDE.  The WiFi password is the one you set in above Testing Image and WiFi Setup section. If you are success to join the WiFi network, you can access the web control interface with the URL  http://192.168.1.1:8080/robot.html. You can control the robot as the previously video demo shows.