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Adafruit Ultimate GPS Breakout, Best Way to Turn Off
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Adafruit Ultimate GPS Breakout, Best Way to Turn Off

by g7bi37 on Sat Sep 08, 2018 10:11 pm

For a project I'm working on I would like to be able to disable / turn off the GPS to minimize power usage.

There are two ways that I know of to turn off the GPS, and I'm wondering if one way is better than the other.

1. The GPS can be disabled by pulling the ENABLE pin to ground by setting a digital pin to OUTPUT with the pinMode function
Code: Select all | TOGGLE FULL SIZE
pinMode(digitalPin,OUTPUT);


2. The GPS can be put into standby mode using the Adafruit GPS library
Code: Select all | TOGGLE FULL SIZE
gps.standby();
or directly using
Code: Select all | TOGGLE FULL SIZE
sendCommand(PMTK_STANDBY);


In this forum post https://forums.adafruit.com/viewtopic.php?p=255149 it is stated that current draw is under ~200uA in Standby Mode. I cannot find any information about power consumption when the ENABLE pin is used.

The amount of time it takes the GPS to turn back on and reacquire a fix is not a factor for my project.

Thanks for any guidance.
Last edited by g7bi37 on Wed Sep 12, 2018 2:28 pm, edited 1 time in total.

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Re: Adafruit Ultimate GPS Breakout, Best Way to Turn Off

by adafruit_support_carter on Wed Sep 12, 2018 1:19 pm

I cannot find any information about power consumption when the ENABLE pin is used.

The ENABLE pin is not a feature of the GPS module but is tied to the onboard voltage regulator. See schematic here:
https://learn.adafruit.com/adafruit-ult ... matic-13-2

So you'd want to look at the datasheet for the voltage regulator to see what it's current draw is when disabled:
http://ww1.microchip.com/downloads/en/D ... ic5225.pdf

Looks like maybe 5uA max? (Ground current in shutdown)

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Re: Adafruit Ultimate GPS Breakout, Best Way to Turn Off

by g7bi37 on Wed Sep 12, 2018 2:32 pm

Thank you, that is very helpful.

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