A proprietary 2.4 GHz link tops out at 2 to 3 m, the body attenuates, 16-channel throughput is fragile. Choosing between WiFi, ESP-NOW and onboard logging.
A portable acquisition system promises real time, but the radio link is often the silent weak point. A proprietary 2.4 GHz link tops out in practice at 2 to 3 usable meters, and that range collapses as soon as the subject's body comes between transmitter and receiver.
Why 16 channels make the link fragile
The human body is mostly water, which absorbs strongly at 2.4 GHz. A subject turning their head attenuates by several dB. In 16 channels, throughput doubles compared with 8 channels, the time window per packet shrinks, and the slightest retransmission drops samples.
The live stream then degrades through silent gaps rather than a clean disconnect, which is worse for analysis.
Three possible tradeoffs
A WiFi shield offers range and application-level buffering, at the cost of latency and power. A serial bridge over ESP32 using ESP-NOW gives a lightweight, deterministic short-range link. Finally, onboard logging to a card gives up the live stream but guarantees integrity, with TTL resync after the fact to realign with the other modalities.
The takeaway: if the live stream is not essential, recording locally and resyncing by TTL always beats an undersized radio link.