BiosensorArray - Timestamp

Integration options

It would be good to write the Data Aggregator Board software (current target board is Arduino MEGA) so that it can use RTC, GPS or both. This would provide maximum flexibility to end user depending on their resources and environment.

Logic:

• POWER UP: If GPS module installed and good signal, then set time from GPS
  • If RTC installed too, then set time from GPS in case GPS signal degrades during operation
• POWER UP: If no GPS module installed or GPS bad signal, then
  • If RTC install & set, then get time from RTC
    • If no RTC installed, then unable to timestamp (serious error condition?)
    • If RTC installed but not set, then prompt for manual time set (how?)

RTC

• Pro's:
  • Cheaper than GPS
  • Always works indoors since it doesn't need satellite signal

• Con's:
  • Requires initial time set
  • Not as accurate as GPS

• Implementations:
  • DS1307-based Real Time Clock module (i2c)
  • RTC used in Heart Spark (i2c)

GPS

• Pro's:
  • Automatic time set
  • Adds geolocation data to biosignal data

• Con's:
  • More expensive than RTC
  • Lacks GPS's inherit benefit of geolocation data

• Implementations:
  • Sparkfun GPS shield + module bundle
    • Available at Microcenter in Chicago, too
  • Adafruit shield
    • just a shield, requires seperate GPS module