Sensors & Hardware
How Wireless Communication Modules Work — ESP32, nRF52840, SX1262
What carries a sensor's measured value outside its enclosure is, almost always, a radio wave. We trace how Wi-Fi's OFDM uses orthogonal subcarriers to overcome multipath, how BLE's GFSK modulation and star topology enable duty-cycled operation, and how LoRa's Chirp Spread Spectrum (CSS) trades range for data rate across the SF7-12 spreading-factor range — all through the real numbers of chips like the ESP32-C6, Nordic nRF52840, Semtech SX1262, TI CC2652R7, and MultiTech mDot. From the 1999 naming drama behind Wi-Fi, to the name Bluetooth born from a 10th-century Danish king's epithet in 1996, to the story of how LoRa, built by a small French startup, was acquired by Semtech, to the real-world example of ZENNER's LoRaWAN smart-meter network scaling past 10 million devices, we look at how to choose frequency band, transmit power, sensitivity, and topology.