GPS Logger
GPS Logger VI – PCB Layout and Case
by nada on Apr.06, 2010, under GPS Logger, Projects
Progress has been made on the GPS Logger over the last month. A sutiable case for the project was purchased, components ordered from Mouser and the circuit board designed. Once the component footprints have been checked off the design will be sent to BatchPCB for manufacture.
GPS Logger V – Full hardware
by nada on Mar.05, 2010, under GPS Logger, Projects
Having determined the battery and power requirements, a full schematic of the GPS logger was made. Buck regulators and Li-Ion battery chargers were investigated from a variety of manufacturers. The TC105 3.3V Buck regulator and the MCP73863 4.2V Li-Ion battery charger, both from Microchip, were chosen to provide the power needs for the project. The circuit is capable of detecting if a USB port is a Charging Port and adjusting the battery charge current to suit.
GPS Logger IV – Power and Batteries
by nada on Mar.03, 2010, under GPS Logger, Projects
The prototype is at the stage of being able to successfully achieve GPS lock, log the received coordinates, waypoints and go to sleep. The power usage of the system needed to be analysed in order to specify the battery requirements. The current draw was monitored after the 3.3V regulator as the device was put into its various modes.
GPS Logger III – NMEA Processing
by nada on Feb.20, 2010, under GPS Logger, Projects
The GPS Logger is currently able to access files and directories on a FAT16 filesystem, contained on a SD card. This post covers processing NMEA with a finite state machine and some of the problems encountered so far with the logger. (continue reading…)
GPS Logger II – GPS Interfacing
by nada on Feb.10, 2010, under GPS Logger, Projects
The system is now up and running. It is capable of communicating with the GPS receiver to get it into a known protocol (NMEA) and baud rate from an arbitrary starting configuration. I had to determine the pinout for the receiver as it was a USB GPS receiver. A check with the multimeter quickly identified the pinout of the four wires, TX was easy to spot as it was a constantly changing voltage whereas RX only changed when a command was sent. Once the prototyping is finished the USB receiver will be restored to its former glory. A few challenges were involved in figuring out the receivers startup configuration. It looks like at reset it outputs NMEA at 4800 baud but expects to receive NMEA configuration commands at 9600. This ‘interesting’ configuration was overcome by sending NMEA and SiRF configuration commands to the receiver at all supported baud rates. (continue reading…)
Building a GPS Logger
by nada on Feb.08, 2010, under GPS Logger, Projects
I like hiking, its a good excuse for getting outside, exploring the countryside, getting fit and having fun. While I can remember the places I’ve been and have photos as well, I would like to be able to record more information about the hike and be able to display the route taken in mapping applications. I have previously used a Laptop and USB GPS receiver in the car to record camping trips, however this is impractical when hiking as weight is an issue and the laptop battery only lasts a few hours. (continue reading…)
