TOPIC
Lessons, explainers, experiments, and implementation notes.
Signal strength can help estimate link conditions, but it is not the whole quality story. A strong desired signal can still be difficult to decode in a noisy or interfering environment. Strength and intelligibility answer different questions.
Channel State Information exposes how multipath changes, which turns ordinary Wi-Fi links into crude environmental sensors.
Someone enters a room and the graph changes. It is a compelling demo, but it is not yet evidence of reliable presence detection. Signals can change for reasons other than a person entering the space.
Setting a calibration value does not guarantee that every future measurement will remain correct. The environment, reference, and operating range in which that value was created are part of its meaning. Calibration is a rule for interpreting a measurement.
RF introduces many concepts at once: frequency, modulation, antennas, packets, routing, and applications. A layer map helps separate physical-signal questions from protocol and application questions.
Keeping the ESP32 focused on reliable CSI capture and moving heavier analysis elsewhere made the sensing pipeline easier to debug.
A sensor message may contain only a few bytes, but many sensors can share the same radio medium. The important question is not only how much data exists, but how long each transmission occupies that shared medium.
Once identity, addressing and transport were layered over LoRa, the experiment stopped being just two radios sending bytes.
The name LoRa is often used as if it describes an entire network. But the way information is represented over the radio and the rules for operating a multi-device network are different layers. LoRa and LoRaWAN are a useful example of that boundary.