Power

Many sensor field problems look like unstable algorithms, ADC jitter, or poor modules. They often end up being ground and power problems.

The reading is stable when the device is idle, but jumps when a motor starts. Temperature moves during radio transmission. Pressure shifts after a relay turns on. USB power and battery power give different values. Short lab wiring works, while the field installation is noisy.

The physical quantity may not have changed. The measurement reference changed.

When a Wi-Fi device turns on power save, the symptoms often look like the network has suddenly gotten worse: ping jitters more, downlink data sometimes piles up, and application traffic appears to lag randomly by half a beat, while the logs show no obvious disconnect. The problem is often neither RSSI nor DHCP. It is that the terminal has intentionally reduced how long it stays awake to receive packets.

The easiest mistake is to describe Wi-Fi power save in one vague sentence: the terminal sleeps for a while, saves power, and then wakes up again to send and receive. What actually determines the experience is how these three things cooperate: