AVR Butterfly Logger

This is a Datalogger to save values from a tipping-bucket rain gauge (a device to measure rainfall intensity, german: Niederschlagsgeber nach dem Wippenprinzip). The gauge shown in the pictures is made by Thies Clima.

All needed electronics is already on the AVR Butterfly. The on-board 4mBit (512kB) Dataflash is used to store the values. Readout to the Windows download software developed for this project takes place via serial port (RS232). Since the dataflash needs up to 45mA during write to flash operations the coin cell on the BF is no reliable energy source. In the logger the coin cell serves as a backup battery and the main power supply are three AA alkaline batteries (the 4th battery in shown in the pictures is just to keep the other three in place). The maximum exernal voltage for the BF is 4,5V according to the manual. The firmware code is based on the gcc-port of Atmels application code.

The main parts of the firmware:

• Real time clock and date (taken from the BF-gcc application port)
• Dataflash low-level access (extended versions of files dataflash.h/.c from the AVR Butterfly gcc-port)
• Dataflash management as a ring-buffer
• Battery fail detection for external batteries
• Debouncing of the rain gauge reed contact
• Power save modifications of the org. BF code
• Logger status display
• Transfer of logged data to Windows software via RS232
• ...

The source code of the firmware is not available. The extended versions of dataflash.h and dataflash.c will be part of the Application gcc-Port Version 0.6.5.

Ongoing development:

• A prototype if a signal conditioning circuit to interface industrial 4-20mA current loops to the Butterflys ATmega169V AD-converter has been developed. High linear opto-couplers have been used to protect the controller (Vishay IL300, thanks to EBV Elektronik for the samples. Agilent HCNR200/201 may be an option - but haven't been available in small quantities for prototyping from the German distributor). Picture of the PCB and the schematic will be available soon.
• A modified version if this datalogger-application is used to monitor the motor-currents in a "robot-war" fighting-roboter. More on this.

Some pictures of the "Rainlogger"

The case-work and the frontpanel have been made by ZBT Elektronik at the Technical University of Kaiserslautern. Please click on the thumbnails for higher resolution pictures.

bf_logger_01.JPG bf_logger_02.JPG bf_logger_03.JPG bf_logger_04.JPG bf_logger_05.JPG bf_logger_06.JPG bf_logger_07.JPG bf_logger_08.JPG bf_logger_09.JPG bf_logger_10.JPG bf_logger_11.JPG bf_logger_12.JPG bf_logger_13.JPG bf_logger_14.JPG bf_logger_15.JPG bf_logger_16.JPG

Screenshot of the Download-Application:

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