pm1's blog archive for September, 2012 - RC Groups
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Archive for September, 2012
Posted by pm1 | Sep 03, 2012 @ 06:57 AM | 94,827 Views
This method modifies the software on the small i2c nav board, that it configures the GPS correctly at every power on. It is done with arduino 1.01. The connection is done via FTDI. There are no pins soldered to the i2c nav board, but the connector is there (6 pins in a row).

The gps exists in 2 versions:
V1. without the ability to store settings permanently (with the onboard battery lifetime of settings is typically fom hours to some days)
V2. can store settings permanently in an onboard eeprom. The rest should be identical

remark V2: some people reporting that rx/tx if i2c may be swapped on i2c board. If you see continously increasing i2c error or garbage data from the sensors, try to swap the two wires

Recipe for V1:
1. Download this version of firmware for i2c nav board: Download
either (Try 2a. If it does not work at every power on of copter, try version 2b, look below for reason)
2a. unmodified gps
2b. solder a bridge between pin 13+14 of gps board (picture included in download), set GPS_SERIAL_SPEED 38400 in I2c config.h
3. use arduino 1.01 to flash i2c_nav with downloaded version (use FTDI)
4. update fc multiwii 2.1 or later with activated #define I2C_GPS and your magnetic declination in config.h of multiwii -> round up to next full degree, but consider sign
5. connect everything
6. If GPS sends valid frames, LED on I2C nav board should blink 100ms on/1s off
7. Calibrate and switch on mag! Check that that copter orientation...Continue Reading