Build an FM radio using an RTL-SDR dongle
Raspberry Pi FM Radio
For the Pi FM radio project in this article, I tried a few different arrangements, but I found that an LCD HAT (hardware attached on top) with buttons (Figure 4) worked best. However, other options such as a PiFace digital HAT (Figure 5) or a button HAT could also be used.


The LCD Python libraries will vary according to the hardware used; however, most LCD HATs are based on the Adafruit libraries [4].
The Python code for the LCD HAT (Listing 2) is based on the simple test code with some additional logic for an LCD button interface and some predefined radio frequencies. The main code loops through, looking at each of the buttons with the lcd.is_pressed()
function. The LCD.UP
and LCD.DOWN
buttons are used for volume control, and the LCD.LEFT
and LCD.RIGHT
buttons cycle through the predefined radio stations. The lcd.clear()
and lcd.message()
functions show the new radio station information on the LCD HAT. In my testing, I used a 0.25-second delay on all the button presses, although you might need to tune this value for your hardware and usage.
Listing 2
Pi FM Radio with an LCD HAT
Summary
Creating a homemade FM radio is just one of the many interesting applications for SDR utilities and the low-cost RTL-SDR dongle [5]. In the future, I would like to add a Python Tkinter or web interface to my FM radio application.
Infos
- About RTL-SDR: http://www.rtl-sdr.com/about-rtl-sdr/
- GNU Radio: https://www.gnuradio.org/
- Code for this article: ftp://ftp.linux-magazine.com/pub/listings/linux-magazine.com/206/
- Adafruit libraries: https://github.com/adafruit/Adafruit_Python_CharLCD
- See more of Pete's Projects: https://funprojects.blog
« Previous 1 2
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Direct Download
Read full article as PDF:
Price $2.95
News
-
Another New Linux Laptop has Arrived
Slimbook has released a monster of a Linux gaming laptop.
-
Mozilla VPN Now Available for Linux
The promised subscription-based VPN service from Mozilla is now available for the Linux platform.
-
Wayland and New App Menu Coming to KDE
The 2021 roadmap for the KDE desktop environment includes some exciting features and improvements.
-
Deepin 20.1 has Arrived
Debian-based Deepin 20.1 has been released with some interesting new features.
-
CloudLinux Commits Over 1 Million Dollars to CentOS Replacement
An open source, drop-in replacement for CentOS is on its way.
-
Linux Mint 20.1 Beta has Been Released
The first beta of Linux Mint, Ulyssa, is now available for downloading.
-
Manjaro Linux 20.2 has Been Unleashed
The latest iteration of Manjaro Linux has been released with a few interesting new features.
-
Patreon Project Looks to Bring Linux to Apple Silicon
Developer Hector Martin has created a patreon page to fund his work on developing a port of Linux for Apple Silicon Macs.
-
A New Chrome OS-Like Ubuntu Remix is Now Available
Ubuntu Web looks to be your Chrome OS alternative.
-
System76 Refreshes the Galago Pro Laptop
Linux hardware maker has revamped one of their most popular laptops.