If you have a GPS module hooked up to your Arduino, there's a good chance you're looking to run it on batteries or some other portable power supply. Here are some hints on what you can use and how to reduce power.
Current power test data: (Please post your own findings to the forums so they can be integrated here)
- 2 Energizer Alkaline AA w/ Mintyboost, logging 1Hz RMC fix data, no sleep - 12 hours
- 2 Energizer Alkaline AA w/ Mintyboost, logging 1Hz RMC fix data, 30s sleep - 16.5 hours
- 2 rechargeable AA w/Mintyboost, logging once a minute with sleep - 30 hours
These are easy enough, pair it with a battery clip or holder with a 2.1mm barrel jack and you can simply run the entire system off of this. Most 9V provide about 400mA-hours of current (~5 hours of run time)
A mintyboost will convert 2 AA's (3V) to USB (5V). You can build it 'as usual' and connect it up via a standard USB cable or wire it up directly as shown above so that it will fit into a smaller case. You can use rechargeables or Alkalines. Provides about 2000 mA-hours of current (~20 hrs of run time)
Huge battery pack
This pack will power the whole setup from the DC jack and last at least 10 longer than a 9V
There's three things that use up power in the GPS logger: the Arduino, the GPS module and the SD card
- The Arduino chip is always using about 10mA of current, maybe a little more if there are LEDs. You can reduce this a lot by making it go to sleep
- The USB chip uses about 10mA as well. If you dont have a USB cable plugged in, this will save you a bit of power
- The GPS module uses between 20mA and 60mA of current, depending on whether it is trying to acquire a lock or whether it is merely tracking. You can reduce this by using the GPSPWR pin to turn the GPS off between reports.
- The SD card uses 20mA but only when writing data. You can reduce this by sleeping between reports and only logging fix data from the GPS which translates to less data written.
The "log everything all the time" configuration draws about 75mA
The "sleep for 10 seconds between reads but don't turn off the GPS" draws about 65mA
If you are outside where the GPS can get a fix pretty quickly, you can use as little as 10mA on average by logging only once a minute and turning off the GPS between logs.