Hardware architecture

Global view of the system.

  • We decided to use a Beagleboard xM as our system's core. It deploys a linux Ubuntu, is compact and provide us with four USB ports. These USB ports are connected to a webcam, a wifi module, our STM32-based PCB and an additional PCB used to drive our three motors. We extended our Beagleboard with a home-made extension board used to amplify our audio in and out.

Schematic hardware architecture

  • Our STM32-based PCB is used to drive a flash memory and a LCD screen. It allows Casper to display pictures on its "face" such as smileys or users pictures taken by the webcam. This part of our achitecture uses FreeRTOS to manage the different tasks. We are totally able to control these features from the Beagleboard using a RS232 link. We designed the PCB ourselves and you can find below their layouts.
Our two-layered PCB.

  •  Casper's movements are driven by three strings, each motor pulls a string to have the robot bend toward the wanted direction. This original architecture is similar to the mechanics of an elephant trunk, giving Casper a great maniability.
A motor pulling one of the three strings.