In the articles RaspberryPi – Install speech output with eSpeak and RaspberryPi – Send FM signals via GPIO pin describes how to use the RaspberryPi to read texts and send FM signals. These two options can be combined so that thanks to the RaspberryPi you are able to send texts read out via FM signals.
How this works and what you need to pay attention to is described in the following article.
Safety instructions
I know the following notes are always kind of annoying and seem unnecessary. Unfortunately, many people who knew "better" have lost eyes, fingers or other things due to carelessness or injured themselves. Data loss is almost negligible in comparison, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Because even the coolest project is not worth injury or other trouble.
https://www.nerdiy.de/sicherheitshinweise/
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Requirements
Before you start this article, you should have prepared the RaspberryPi so that it can be reached via the network and controlled via SSH. In addition, the voice output with “espeak” should already work and also the sending of FM signals.
The following three articles describe what needs to be done to prepare the RaspberryPi:
RaspberryPi – setup for nerdiys!
RaspberryPi – The first configuration!
RaspberryPi – Control the RaspberryPi via SSH
RaspberryPi – Send FM signals via GPIO pin
RaspberryPi – Install speech output with eSpeak
Required tool:
-no-
Required material:
In the following list you will find all the parts you need to implement this article.
Important words first
Sending FM signals (and many others) via unauthorized radio transmitters is not legal in Germany. The method shown below allows you to do exactly that. Please use it responsibly. Above all, make sure that you do not disturb any regular radio stations. The method shown is comparatively powerful and also radiates into other frequency ranges. This means that you can very easily incur the displeasure of your neighbors and thus also the Federal Network Agency.
Log in to the RaspberryPi via SSH
To start, you must first log in to the Rasp Pi with Putty via SSH. How to do this is in the article RaspberryPi - Control the RaspberryPi via SSH described.
The command combination
To combine voice output with sending FM signals you must use the following command structure. The speech output from espeak is redirected via stdio and saved as a .wav file. Immediately afterwards the fm_transmitter is called to play exactly this file and send it via FM. (Many thanks to Muhammet for the tip. :))
You can use the text “Hello world, can you hear me?” of course replace with any other text. The FM frequency can also be set – as in the article RaspberryPi – Send FM signals via GPIO pin described – set.
espeak -vde "Hello you big world out there!" --stdout> /tmp/tmp.wav && sudo /home/pi/fmtrans/fm_transmitter/./fm_transmitter -f 102.00 /tmp/tmp.wav
Have fun with the project
I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂
PS Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂
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