I used a Realtek RTL2838 DVB-T dongle and rtl_433 to capture 433 MHz RF signals on Arch Linux, after installing the rtl-sdr-librtlsdr-git driver and recompiling rtl_433. A Python script detects my doorbell press and sends notifications via MQTT to Node-RED, which then alerts my Echo Dots and iPhone. Now I can add more devices on this frequency! 🚀 #DIY #IoT #SDR #HomeAutomation #Tech