In a previous blog posts, I wrote about the FM receiver on the Nokia N900. I commented

You are supposed to be able to get RDS as well, but I didn’t get any RDS messages. All in all, the fmradio package is fine for my use, but nothing special.

Since then, I started playing with the FM Transmitter built into the N900, and when you start playing with both of them, it can get very interesting. For the FM Transmitter, there is a client that you can use to control the transmitter, fmtx_client.

With this, you can set the frequency, the RDS Station name, the RDS information text as well as power on and off the transmitter. I ran into one bug, with the current firmware level of my phone, the station name needs to be exactly eight characters long. However, you can control pad the station name with blanks.

Our car is a Prius which has a nice RDS enabled FM receiver. With a little playing around at the command prompt, I set up the FM transmitter to set the radio station to “aldonsfm” and sent out messages to my family members. The Prius has a safety feature that it won’t display RDS messages when the car is in motion, so I didn’t play with it extensively. However, with a little work, it seems like I could set up the phone so that it would display the most recent SMS message I’ve received on the RDS receiver whenever the car is stopped. I also talked with my wife about how this could be a great idea for car salesmen. When a potential buyer checks out the car, it has music selected to their taste playing on the radio, broadcasting off of the salesperson’s N900, along with appropriate ads for the car company, and could have personalized RDS messages display for the potential buyer.