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I have a 2011 BMW 520D, and it has a very large display for media and sat nav. The car supports showing traffic information via TMC (Traffic message channel), but not in Ireland. When I visit Northern Ireland, it does pick up the TMC station and shows me details of traffic...

Since the Raspberry Pi can be used as an FM transmitter, I am wondering can I take the pi and turn it into a TMC transmitter (I think it's RDS that's used to send traffic info) transmitting on the station that it uses in the UK? The theory being that I pull the information from Google or another traffic source (or multiple sources for that matter, possibly including the Irish TMC, which my car does not support), recode it and transmit it in a way the car can use... Possible?

[UPDATE] Just to clarify: The traffic info can be received from anywhere (Google, Bing, Here Maps as suggested by @user12321). That is not actually the problem. The problem is more the encoding and retransmitting the data using the TMC station...

[UPDATE2]: Ok, after a lot more digging, i found out something... my theory of the TMC being encrypted is somewhat true, but also a little wrong. BMW do not have the TMC database in their nav system, so, even though they technically could "here" the TMC info, they dont know where it is... TMC might say 0122,33223,163322 where 01 is the type of issue and 22 is heavy trafic, 33 is road and 223 is, say M50 north bound between N7 and N4 and 163322 is a start time... BMW can read this, but have no idea what it means...

TiernanO
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  • hey, did you ever implement this? – maaw Jun 21 '18 at 13:55
  • nope... ended up finding out that TMC has codes, which is what the car uses to figure out where the issue is and what the issue is... and since my car does not have the list of TMC codes for Ireland, it ended up being useless... ended up just mounting an iPhone to the dash and using Waze... :) – TiernanO Jun 22 '18 at 09:14
  • well that's sad :( I live in Argentina and own a Peugeot 207 with in dash nav, Here the things are kinda complicated too, but I'll do some research and see what I can find! – maaw Jun 22 '18 at 12:59

2 Answers2

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After a lot more digging, i found the following: Defcon 15 - Injecting RDS-TMC Traffic Information Signals (YouTube Video, PDF). Now to use this for good, not evil...

TiernanO
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Scrap my previous answer.

This is a program which takes wav files and plays them over FM radio and also supports RDS. It works quite well (according to other people on Reddit) and should be what you were looking for.

Beta Decay
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  • The problem is not getting the traffic info, though the Korean of that I get, the better. The problem is more sending it over Fm to the car... – TiernanO Aug 08 '14 at 11:18
  • @TiernanO Ohh. You could send the text data to a TTS engine (you can get one in Python) and connect the Pi to an FM transmitter that connects via audio jack (available in Maplin). – Beta Decay Aug 08 '14 at 11:20
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    Its not audio that needs to be transmitted. The TMC station is a station that piggybacks on a normal station (in Ireland, its RTE Raido 1). There is a data signal (using RDS) that includes traffic conditions. My theory is to take the data from the internet, as you suggested, encode it into the TMC format and broadcast it to the car... Hope this clarifies things... – TiernanO Aug 08 '14 at 11:29
  • that does look interesting... The RBDS stuff (https://learn.adafruit.com/adafruit-si4713-fm-radio-transmitter-with-rds-rdbs-support/test-and-usage) looks like it getting me closer to my goal! – TiernanO Aug 08 '14 at 11:36
  • your latest answer looks like it gets me even closer again! Now to figure out what i need to send over RDS to get TMC to work! – TiernanO Aug 08 '14 at 11:41
  • @TiernanO Some GPS systems have the ability to tune the TMC lookup frequency. I can't see online if your car has that option but it might be in settings – Beta Decay Aug 08 '14 at 11:52
  • I can't see it in there... I think the problem is that the tmc signal is encrypted and bmw don't have the key... – TiernanO Aug 08 '14 at 12:34