Lisa

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Lisa ( the Lost Illusions Serendipitous Autopilot) is a range of autopilots based on STM32 microcontrollers ( CortexM3@72Mhz ) designed to run Paparazzi. There's no such thing as a perfect autopilot, only autopilots adapted to a particular purpose. This is the reason why the Lisa autopilots come in different styles for different uses.

The first members of the family are:

  • Lisa/L, a design where the STM32 is associated to a gumstix Overo.
  • Lisa/M, a design focusing on cost and simplicity.
  • Lisa/S, a design focusing on size and weight.

Lisa/L

Description

Lisa/L is a dual processor board autopilot designed to allow for the possibility of using Linux for Paparazzi airborne code.

Lisa l bloc diag simple.png Lisa l top.png Lisa l bot.png

Documentation

The documentation for Lisa/L is broken into several parts due to board complexity and Gumstix Overo integration.

Lisa/M

Description

Lisa/M is a great general purpose small-footprint autopilot. There are currently two versions that have been produced. Detailed documentation can be found here:

Lisa/M v2.0 Top View


Lisa/M v1.0 Top View

Usage scenarios

There are many potential applications for the small, relatively inexpensive and flexible Lisa/M. For regular Autopilot boards a fully equip Lisa/M board is needed. For some scenarios just a basic Lisa/M without an IMU and barometric pressure sensor is needed, which reduces the board cost. Here are some ideas (not all have yet to be implemented):

  • As a basic Autopilot
    • To use the Lisa/M as an autopilot, you need to attach a GPS receiver. A nice uBlox LEA-5H or newer will perform great.
  • As an advanced Autopilot
    • Additional sensors for measuring airspeed, current, etc. would enhance a fixed-wing airframe.
  • As a servo extender
    • Sometimes being able to control seven actuators is just not enough. Large airframes may require flaps or an airbrake and automatic landing facilities. Maybe special ACL/Nav lights, or four cameras with zoom. By using a coupled second basic Lisa/M and connecting this to the master Autopilot board we can extend the amount of servos. Large airframes can also benefit from remote and/or redundant servo drivers.
  • As a Safety Pilot Device
    • To provide an extra safety level required in some UAS challenges. A second Lisa board can make it easy to adhere to the rules for such a challenge.
  • As a Data Logger
    • Maybe you have a need only to log all kinds of data, like temperature, volts, amps, height, airspeed, and not control the aircraft. For this we can setup a Lisa/M board. Collecting this data can be to a storage medium like on a micro SD card. Sometimes there is no need for real-time data collection through telemetry but just for storing a huge dataset.
  • As a Camera controller
    • On some models that do not require many servos (for example - flying wing with only 3 channels used), spare channels can be used for camera control. In addition, it could be used as an independent pan-tilt unit (PTU) controller.
  • As a Airframe Tracker
    • Tracking an airframe for an antenna or camera on a tripod is one of the many optional uses for a Lisa/M Board.

Lia

Lia is a lower-cost variant of Lisa/M 2.0. The microcontroller, basic layout, servo outputs, and mounting holes are the same. Major differences:

  • 0.1" through-hole connections for non-servo I/O instead of Molex picoblade
    • PCB size increased slightly to (58x34mm) to accommodate throughholes
  • CAN transceiver removed on initial units; populated on later units (see documentation)
  • barometer removed
  • I2C level shifter removed
  • 5V voltage regulator removed
  • Added provisions for multiple BEC input balancing on servo connectors

Lia v1.1 Top View


Lia documentation

Lisa/S

Lisa/S is very small autopilot board. The focus for this design is size, weight and power consumption. It's an autopilot suited for the smallest airframes.

Lisa S V0 1 r2 on finger.jpg