[maemo-developers] FM RDS data

[From: Martin Grimme]

Hi,

I would imagine that the signal strength can be read using V4L2
interface on /dev/radio0.
I was able to set frequency with this interface and IIRC I also read
signal strength from it already at a time when I was thinking that
/dev/radio0 was the FM _receiver_.


Martin


2010/1/7, Simon Pickering <S.G.Pickering at bath.ac.uk>:
>
>> > I'm thinking of a small usage, a app that found the freest frequency
>> > (by listening fm with the transmitter) and change the frequency of
>> > transmitted music to the found one and send an rds signal by the
>> > transmitter, so you don't have to change frequency on your
>> car receiver (or everything else).
>
> Great to hear this, I was thinking of trying something similar when I had
> some time. The FM transmitter also has a basic receiver built in (afair from
> the spec sheet), i.e. not the one that is built into the Bluetooth chip that
> is used to listen to the radio, which I imagine is designed for just such a
> usage (I think it just returns a signal level for each frequency, but I'd
> have to take another look at the sheet to be sure) does anyone know if we
> can access this at the moment?
>
> Cheers,
>
>
> Simon
>
>> -----Original Message-----
>> From: maemo-developers-bounces at maemo.org
>> [mailto:maemo-developers-bounces at maemo.org] On Behalf Of Martin Grimme
>> Sent: 07 January 2010 07:23
>> To: Benoît HERVIER
>> Cc: maemo-developers at maemo.org; Aldon Hynes
>> Subject: Re: FM RDS data
>>
>> Hi,
>>
>> yes, RDS PS and RDS RT can be modified. See
>>
>> http://wiki.maemo.org/Documentation/Maemo_5_Developer_Guide/Us
> ing_Multimedia_Components/FM_Transmitter_API_Usage
>>
>>
>> Martin
>>
>>
>> 2010/1/7, Benoît HERVIER <khertan at khertan.net>:
>> > About FM and RDS modifying RDS signal transmited from the tablet is
>> > possible ?
>> >
>> > I'm thinking of a small usage, a app that found the freest
>> frequency
>> > (by listening fm with the transmitter) and change the frequency of
>> > transmitted music to the found one and send an rds signal by the
>> > transmitter, so you don't have to change frequency on your
>> car receiver (or everything else).
>> >
>> > I know that fm transmitter emit an rds signal ... but can
>> that be changed ?
>> >
>> > Does there is documentation about the fm transmitter and receiver
>> > somewhere on Maemo ?
>> >
>> > Thanks a lot
>> >
>> > 2010/1/6 Martin Grimme <martin.grimme at gmail.com>
>> >
>> >> Hi,
>> >>
>> >> the FM receiver's interface for RDS is exposed via sysfs. So any
>> >> application can read RDS data from it.
>> >> The frequency bands the receiver is capable of are US/EUR (87.5 -
>> >> 108.00 MHz) and Japan (don't remeber, but I think starts
>> somewhere at
>> >> 70 MHz). A region switch in the driver (sysfs-Interface
>> again but as
>> >> root) switches between the frequency bands.
>> >>
>> >>
>> >> Martin
>> >>
>> >>
>> >> 2010/1/6, Aldon Hynes <Aldon.Hynes at orient-lodge.com>:
>> >> > I have been approached by a person interested in sending
>> data from
>> >> > a
>> >> sensor
>> >> > via FM to a cellphone which would in term transmit this
>> data to the
>> >> > Internet.  I am interested in figuring out if this is something
>> >> > that
>> >> could
>> >> > be done with an N900.  With that, I have a few specific
>> questions:
>> >> >
>> >> > First, can anyone point me to information about how to
>> >> > programatically receive RDS data?  I've read that the FM receive
>> >> > app is supposed to do
>> >> that,
>> >> > but I haven't managed to receive RDS data that way yet,
>> and I don't
>> >> > have
>> >> the
>> >> > source code.
>> >> >
>> >> > Second, does anyone have any idea what frequencies the
>> FM receiver
>> >> > can
>> >> tune
>> >> > into?  The programs I've seen have focused on the traditional
>> >> > commercial
>> >> FM
>> >> > band, 88 Mhz to 106 Mhz.  Can the FM receiver tune in higher or
>> >> > lower frequencies?  If so, what is the real frequency
>> range of the
>> >> > FM Receiver.
>> >> >
>> >> > Third, are there other data formats that can easily be
>> sent and/or
>> >> received
>> >> > from the Nokia phone?  If so, can people point me to any
>> of these
>> >> > other
>> >> data
>> >> > formats?
>> >> >
>> >> > Any help you can provide would be greatly appreciated.
>> >> >
>> >> > Aldon
>> >> >
>> >> > _______________________________________________
>> >> > maemo-developers mailing list
>> >> > maemo-developers at maemo.org
>> >> > https://lists.maemo.org/mailman/listinfo/maemo-developers
>> >> >
>> >> _______________________________________________
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>> >>
>> >
>> >
>> >
>> > --
>> > Benoît HERVIER - http://khertan.net/
>> >
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