During the weekend I had some time to look at how to disable the combined WiFi and Bluetooth module on the Gumstix Overo Fire. The power source for the onboard video recorder consists of two 1 Ah LiPo batteries and although I did not have any measurement of the power consumption I knew this should be enough for at least one hour even with WiFi and Bluetooth switched ON during the flight (the wall plug adapter is 5V 1A). Still, I wanted to try to disable the WiFi and Bluetooth module since they are not needed during the flight.
Fortunately, I didn't have to look for long because there has already been discussions about this topic on the Gumstix users mailing list. According to this thread, all one has to do is to set the GPIO164_BT_nRESET and GPIO16_W2W_nRESET signals to 0.
# disable wifi echo 0 > /sys/class/gpio/gpio16/value
# disable bluetooth echo 0 > /sys/class/gpio/gpio164/value
Doing so reduced the power consumption from 400 to 210 mA when the Gumstix Overo Fire is mounted on the Summit board (slightly higher on the Tobi). This is great because I can now be even more sure that the batteries will last more than an hour. I do not yet know how much the camera consumes but it can hardly be more than few hundred mA and definitely below 500 mA due to USB limits.
The video below shows the how the power consumption evolves from power on and until the WiFi and Bluetooth are switched off.
Watch video on YouTube.