Build an FM radio using an RTL-SDR dongle
Pi FM Radio

Lead Image © margaritatkahcenko, 123RF.com
Low-cost RTL-SDR dongles can read frequencies between 24 and 1,766MHz. We built a simple FM radio with a Raspberry Pi, a USB dongle based on the RTL2832U chipset, an LCD HAT, and some Python code.
FM radio projects that use chipsets with a low-level Inter-Integrated Circuit (I2C) interface, like the RDA5807M and TEA5767, can work, but I found that both solutions have some drawbacks. The RDA5807M chip is poorly documented, with only Arduino C libraries, and the TEA5767 chip has no volume control.
Software-defined radio (SDR) offers a higher level interface that allows access to mixers, filters, amplifiers, modulators/demodulators, and detectors on the hardware. A wide range of hardware supports SDR, and the RTL-SDR [1] USB dongles based on the RTL2832U chipsets are well-priced at $10-$15.
SDRs have a large list of supported applications; some of the cooler projects include tracking airplanes, free-to-air TV, and monitoring satellite data.
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