Thursday, February 18, 2010

PIC Based GPS to SD-Card Data Logger

Microcontroller - PIC Based GPS to SD-Card Data Logger
This project combines a GPS receiver module, a Microchip PIC microcontroller and a Secure Digital memory card to make a GPS data logger. With a large capacity and reasonably long battery life it is a very useful device for logging GPS position for example for mapping with OpenStreetMap.

The data from the GPS is logged every second with the raw NMEA sentences being written to the SD card. The data written to the card is the GSA, GGA, RMC and GSV sentences which by excluding the carriage returns this should never exceed 512 bytes per second. The data contains:
  • GGA - 78 bytes - time, fix, lat, long, altitude, horizontal dilution of precision.
  • GSA - 69 bytes - fix (none, 2D, 3D), satellites used, dilution of precision.
  • RMC - 78 bytes - time, lat, long, speed, course, date.
  • GSV - 74 bytes - satellite information (4 messages).
The total active power consumption is about 40mA to 45mA when active which in theory should give 48 hours on rechargeable batteries with 2000mAh capacity. In practice I have measured a time of 40 hours.

Download : schematic and source code
related serch : Microcontroller Circuit Project, GPS, SD Card, Data Logger, PIC (src)