This is a test program to study the capability of a GPS module to control navigation of a robot in an outdoor environment.
It is available at: http://mbed.org/users/guiott/programs/LeonardoMbos/m4jtr1
- mbed LPC1768 board
- RTC battery backup
- mbed LPC1768 Workshop Development Board http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=608
- Garmin GPS 15L module
- Garmin GPS active antenna
- serial level adapter (MAX232) between GPS module and mbed serial port
- battery control circuit with step-up converter from 3.7V to 6V
- LCD display 20x4
underneath the cover:
- 3.7V LiPo battery
- 5V LDO regulator
- resistor ladder
This version is developed within the mbos RTOS: http://mbed.org/users/AndrewL/libraries/mbos/lqn3ca
It uses NMEA library by Tim (firstname.lastname@example.org) ported by Ken Todotani http://mbed.org/users/todotani/ on public mbed library http://mbed.org/users/todotani/programs/GPS_nmeaLib/5yo4h also available, as original universal C library, at http://nmea.sourceforge.net
The original gmath.c has been modified to fix a bug in nmea_distance_ellipsoid() function according to bug report ID: 2945855
// while ((delta_lambda > 1e-12) && (remaining_steps > 0)) original by xtimor while (( remaining_steps == 20 ) || ((fabs(delta_lambda) > 1e-12) && (remaining_steps > 0)))
the original code always returns a zero distance if the arrival point longitude is equal or smaller than the starting point one.
The mbed module is interfaced with a Garmin GPS sensor (used in standard mode) with an external antenna, a 20x4 LCD text display and a 5 keys keypad interfaced on a single ADC port via a resistors ladder.
A curiosity: All the hardware components of the test set are mounted on the top of a wooden box, looking like a kind of a steampunk navigator. When my daughter looked at the box she said: "it looks alike the navigator of the da Vinci car". This is the reason why the name of this project is "Leonardo".
This is not a definitive application but a study program to test NMEA full decoding library and a first approach to an RTOS. Many thanks to Andrew Levido for his support and his patience on teaching me the RTOS principles from the other side of the Earth.
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