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SPIF in the Alpha project


The aim of the Alpha project is to build a lenticular autonomous airship for photography and cinema (in french "Aeronef Lenticulaire pour la PHotographie Aerienne").

There are three partners in this project:
  • Airstar, a french company which designs and builds the 10 meters diameter lenticular airship.
  • Animat'Lab, a french university lab (Lip6-Paris VI) which designs and tests the high level software of the airship.
  • Our E.N.S.T. lab, which designs and builds the embedded computing system supporting the flight control hardware and software, the sensors management, the motors handling (propellers and wingtips) and the software interfaces.



The main board is Linux© powered: this airship is probably the first Linux© powered airship of the world.
In this project we used the SPIF2 board, initially developed in 2000-2001 as a robot main board and realtime teaching platform. Linux© can be booted from the network or a serial line and, in this project, we used a 802.11 link for booting and telemetry.

Main board hardware

  • dimensions: 16x12 cm
  • Motorola PowerPC© MPC860
  • 512 Ko FLASHrom
  • 16/32 Mo page-mode DRAMs
  • BDM port
  • 20 pins connector for a classical 8 bits alphanumerical LCD screen.
The board offers standard communications interfaces:
  • 6 serial lines
  • 10BaseT ethernet
  • I2C bus
It provides a wide range of input output interfaces :
  • PCI interface.
  • three PWM outputs
  • many standard inputs/outputs on an extension connector




Special Alpha system features



To drive the seven motors and the wingtips, we added another board, based on a H8 Hitachi processor. This board has 16 PWM channels. It also supports the airship security management, by switching on request to a manually radio control. It communicates with the main board by a serial line.
The I2C bus is used as embedded sensors bus: we design several small boards, based on Microchiip© PIC microcontrollers. These home-made sensors boards drive an inclinometer, a thermometer, an airspeed meter, an altimeter.
Finally, we added a GPS, a laser telemeter and an electronic compass on serial lines.