Turn off just radio chip?

[mwhitley]

There are times I'd like to keep the microprocessor awake and running commands but would like to power the radio chip down to save power. Is this possible?

[mgenti]

Yes, you can turn off the radio's receiver by issuing the command:

rx(False)

and then to turn it back on:

rx(True)

[kbanks]

The SNAPpy command you want is rx(True/False).

I assume you are working with a node that is either controlled serially, or is completely autonomous. Using rx(False) is useful in these cases.

rx(False) will turn the radio off. WARNING! You will not receive any messages over the radio if you do this (The radio cannot be woken up "over the air").

rx(True) will turn the radio back on.

Even without doing a rx(True), if you cause something to be sent over the radio (make an rpc call for example), the radio will automatically be turned back on. (you can turn it back off in your script, you just need to be aware it does this).

[mwhitley]

Awesome. Thanks for the info.

Do you happen to know the current draw when the radio chip is off?

[kbanks]

Unfortunately I don't have that number in my notes (we were more focused on current draw using the sleep() function last time I had a current meter hooked up to my unit than in the rx() function).

The Freescale data sheet says RX On is 37-42 milliamps, and radio off is 1 microamp. So I would expect the measured current savings from rx(False) to be in that ballpark.

[mwhitley]

Thanks for the info!