GPS Logger

Version 1

Description

A solar powered, battery backed up GPS logger.

Parts List

• Solar Cell
• Atmega368P
• Sparkfun MicroMini GPS Module - $90
• Sparkfun uSD DOS-on-Chip module - $45

Total cost around $150.

Version 2

Goals: Cost reduction and power reduction.

• Replace the DOS-on-Chip module with a homespun. Saves: $40.
• Integrate GPS module on board? Saves: $63
• Error indicator light.
• Accelerometer for inactivity detection. ADXL345. Adds: $4.70 (Q100)
• Wake up button. Double tap interface to force a log.
• Sensors: Temperature, Sunlight, Humidity.
• Switch to At90USB for the main processor.
• Built-in booster and USB port for phone charging.
• Uses the phone's GPRS/3G connection for uploading data to website.
• Battery meter

Parts cost under $50.

Discussion

Processor:

• Atmega328P - $3.60

Micro-SD writer from Sparkfun:

 MicroSD FAT Writer from Sparkfun - $44.95

GPS Module:

• u-Blox
• USGlobalSAT
• Tyco (A1035-C or A-1080A or A-1082A)
• Sparkfun MicroMini - $90

Process map:

• Read NMEA sentence once per minute.
• compress it.
• When we get a large enough block, write it out to the card.
• sleep

Features:

• Solar charging
• Adaptive logging rate. Selects logging rate based on how fast you're going. Puts GPS to sleep during breaks.

Going to need:

• Low voltage detection so we can dump sentences out to disk and power things off.
• Lithium Ion Charger - MAX1811
• Power manager - Or do these devices already have it?
• Will I need to down-volt?
• Button to trigger an immediate log.
• Weatherproofing. Especially of the card slot.

• Two pins to talk to the GPS (Use the built-in UART)
• Three pins to talk to the card writer.

Modules

Power Module

• Monitors incoming sunlight via ADC.
• Responsible for charging the battery and informing the Arduino of a low voltage condition.
• Provides GPS Module, Arduino, and SD Logger with power.
• Power switch or button
• Will charge from USB (or Mintiboost)
• Will charge a USB device (built-in mintyboost)

Output Module

• Blinks an LED whenever the processor is awake.
• Some sort of power level indicator?

Processor Module

• Contains the CPU