Rundflug durch die Oberlausitz Fliegerclub Eibau-Oberlausitz e.V. Sektion Ultraleicht

Flight Logger 1.2

Flight time logger with PIC airborne computer

The problem

Did you ever forget to take a note of your landing time? Me too...

D-MNTH Cockpit TOBIK FlightLogger Differential pressure sensor

The solution

  • A airborne computer with a microcontroller (here: PIC 16F876A) and a differential pressure sensor detecting IAS. The recent 255 flights are saved in flash memory together with the pilot.
  • A alphanumerical LCD-Display with 2x16 characters display date, time, pilot and flight status (airborne/on ground).
  • For comfortable handling we add a rotary encoder.

Version 1.00

Version 1.2

  • Design change: Clock with RTC.

    Implementation of the clock inside the firmware with a standby power supply revealed some issues: The FlightLogger cannot be reset except disconnection the standby power supply. Date and time are now kept in a seperate RTC chip, buffered with a lithium battery.

    The standby power supply was dropped completely. That raises safety because the Flightlogger is complete disconnected with main avionics switch now.

    At the other hand we increase robustness because the Flightlogger is booted with avionics switch.

  • Firmware change-over from assembler to C.

    We avoid the time consuming assembler programming. Further development is more easy.

    I decided for C2C Compiler from Pavel Baranov. C2C offer a stable platform for reasonable price. Biggest shortcoming are missing pointers for function returns. But with BoostC a successor is in sight which will address this deficit.

  • Multimedia Card MMC

    The hardware design is prepared for the connection of a MMC. But the firmware is not finished yet. So this part remains unpopulated.


Circuit board


Parts breakdown


Some ideas for development

  • Data transfer to PC via MMC
  • Personalization from MMC
  • Data transfer to handheld via BlueTooth
  • Data transfer to handheld via IrDA (Unfortunatly the Symbios Irda implementation of my Nokia is incompatible to Michrochips MCP2150)
  • Changeover from Oppermann differential pressure sensor (out of stock) to Motorola Sensor DP2010
  • Static pressure sensor as vario/altimeter.
  • Acceleration sensor als G-Meter


A excellent introduction to PIC is which helped me start the project at all. I am flashing the PICs with Spruts Brenner5 (hardware) and PBrenner (software).