N900 FM Receiver. - Page 7 - maemo.org

javispedro | # 61 | 2009-10-12, 15:35 | Report

Would using an "optimized" app for piping v4l input to pulseaudio (instead of gst), possibly with large buffers even at the cost of audio latency help with battery requirements?

pycage | # 62 | 2009-10-12, 15:51 | Report

Originally Posted by javispedro View Post

Would using an "optimized" app for piping v4l input to pulseaudio (instead of gst), possibly with large buffers even at the cost of audio latency help with battery requirements?

Most likely not, because it's not v4l input, but the DAC route of the Bluetooth chip. The chip would also support an I2S audio route but I have no idea how to use that, or if it's possible at all. Nokia confirmed that capturing was the way to go.

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thecursedfly | # 63 | 2009-10-12, 16:05 | Report

Originally Posted by pelago View Post

It's a shame this isn't possible. For people wondering why you would want to do this, I can think of one possible use-case, and that is to mute the radio if receiving an incoming call (hands free, of course) while driving. If using the car's own radio tuned directly into the station, you would have to mute it by hand.

maybe it could be accomplished this way:
you set an application (unexistant yet) on the N900 to transmit a silent track to a certain frequency you chose, which is the frequency of the radio station you're listening to; you receive a call, and the N900 begins automatically to overwrite the radio station with the silent track.
This would need that it's possible to use the FM transmitter while in a call, and to set the frequency again every time you change radio station in the car (maybe it's easier providing a large slider on the screen for that). But maybe it could work

Anyway, with this ipothetical solution you wouldn't drain the battery that fast, since the transmitter would activate only when in a call, and the receiver wouldn't be active at all. (Imagine you don't have a car recharger

)

Last edited by thecursedfly; 2009-10-12 at 16:09.

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pelago | # 64 | 2009-10-12, 16:09 | Report

Interesting idea! But when I've used FM transmitters in the past, I found that the commercial station overrode the little transmitter, not the other way round.

thecursedfly | # 65 | 2009-10-12, 16:15 | Report

oh, I tought that being the phone so close it had at least the power to overwite the commercial station.. I think I've read somebody stating so too..
well, it may need somebody to test it first I guess.

Nexus7 | # 66 | 2009-10-12, 16:17 | Report

Originally Posted by pelago View Post

It's a shame this isn't possible. For people wondering why you would want to do this, I can think of one possible use-case, and that is to mute the radio if receiving an incoming call (hands free, of course) while driving. If using the car's own radio tuned directly into the station, you would have to mute it by hand.

I read (in another posting IIRC) that the N900 will mute the FM when a call comes in, I assume it will transmit silence in this case.

Master of Gizmo | # 67 | 2009-10-12, 19:45 | Report

Originally Posted by eiffel View Post

Guys, before you get too excited please note that the FM transmitter automatically turns off when you connect any cable except the charger. Therefore we know that the FM transmitter uses an internal antenna.

Perhaps the plug _is_ the transmitter antenna and you aren't supposed to plug anything in so you don't exceed regulatory limits with such a good antenna ...

BTW: Has anyone got the "FM Radio" (receiver) application from extras to work? When i try to use it it doesn't work and my system log says:

bcm2048: 3-0022: BCM I2C error!
bcm2048: 3-0022: Is Bluetooth up and running?
bcm2048: probe of 3-0022 failed with error -5

And yes, bluetooth is up and running ...

pycage | # 68 | 2009-10-12, 19:58 | Report

Originally Posted by Master of Gizmo View Post

bcm2048: 3-0022: BCM I2C error!
bcm2048: 3-0022: Is Bluetooth up and running?
bcm2048: probe of 3-0022 failed with error -5

And yes, bluetooth is up and running ...

Which firmware version do you have?
Try this command (one line) in the X-Terminal

Code:

dbus-send --system --print-reply --dest=de.pycage.FMRXEnabler /de/pycage/FMRXEnabler de.pycage.FMRXEnabler.request

It will return a device path and a number. The meaning of the number is:

- OK = 0:
Everything is OK and the receiver can be used
- BLUETOOTH_FAILURE = 1:
There was an error powering up the Bluetooth chip
- I2C_FAILURE = 2:
There was an error powering up the I2C bus
- DRIVER_FAILURE = 3:
There was an error loading the driver module
- TUNER_FAILURE = 4:
There was an error turning on the FM tuner

Maybe rebooting the device will help.
If you have a very old prototype from before September, then the Bluetooth chip is a different one and there's no FM receiver on it.

Master of Gizmo | # 69 | 2009-10-13, 09:03 | Report

Originally Posted by pycage View Post

Which firmware version do you have?

- DRIVER_FAILURE = 3:
There was an error loading the driver module

If you have a very old prototype from before September, then the Bluetooth chip is a different one and there's no FM receiver on it.

It's one of the devices they gave out on the summit and it's error 3 which was to be expected since what i posted were error message from the driver failing to access the hardware.

Is one of you successfully using this on one of the summit-units?

qwerty12 | # 70 | 2009-10-13, 09:12 | Report

pycage:

Nice work, thanks. It works well for me on 41-1 (39 was giving me problems with it).

Just one feature request, however: A way to manually input the station's frequency would be nice. The slider is a little trigger-happy in the fact that it jumps a lot of frequencies, IMHO.