~50 µA ESP-NOW Outside BME280 Node; with LoRa Wake on Radio, part of three node "Heating System Monitor IV"

RE: ~50 µA ESP-NOW Outside BME280 Node; with LoRa Wake on Radio, part of three node "Heating System Monitor IV"

AB9NQ-William — Sat, 05 Sep 2026 15:51:18 GMT

Project has developed into "HVAC System Monitor"; instead of using radioLib library; now using Samtech's SX1262 register level driver commands Changed to Samtech.'s SX1262, rxDutyCycle.

"RxDutyCycle is a special RX mode that allows decreasing power consumption by putting periodically the radio in reception, while keeping the microcontroller in sleep mode. When a packet is received by the SX1261/2 it triggers an interrupt for the microcontroller in order to wake it up." --from Samtech application note AN1200.36.

Beginning results were not promising. Wake-on-radio was achieved; however average rxDutyCycle current was ~94 µA higher than the "Heating System Monitor IV" average dutycycle current. Trying different values of "ticks" for the sleep period; arrived at 5200 symbols from a starting point of 1200 symbols. Formula for "ticks" was in "AN1200.36" Application Note. Achieved a combined rx period and sleep period average current of ~38.32 µA and a sleep period average of ~21.98 µA.

Nordic Power Profiler Kit 2 Observations --new

"HVAC System Monitor" Project source code and documentation

Logged data includes: NTP timestamp, outside temperature, inside temperature, inside humidity, thermostat setpoint, elapsed blower minutes (per cycle), daily total blower minutes, outside pressure, inside pressure, pressure difference (out − in), cycles today, coast minutes (hold time between cycles), and average cycle minutes. Each record is written to both a local LittleFS log file and a perpetual Google Sheet (month-to-month, year-to-year).

RE: ~50 µA ESP-NOW Outside BME280 Node; with LoRa Wake on Radio, part of three node "Heating System Monitor IV"

AB9NQ-William — Thu, 06 Aug 2026 02:23:16 GMT

~38.19 µA average current, ESP-NOW Outside BME280 Node

Update 8/5/2026 Switched to Channel Activity Detection (CAD) Interrupt on EoRa-S3-900TB, ESP-NOW BME280 outside node; from sx1262 "radio.startReceiveDutyCycleAuto()."

Nordic Power Profiler Kit 2 ~38.19 µA Average Current

Project Files updated 8/5/2026

Methodology note — CAD supersedes autoDutyCycle: The Hackster write-up’s published figures (51.30 µA average, ~83.5 months) were measured under the earlier autoDutyCycle WOR detection method. The project has since moved to CAD (Channel Activity Detection) as the pre-check ahead of the WOR receive window, which measurably reduces average current — 38.19 µA vs. 51.30 µA (a 25.6% reduction), improving theoretical battery life by 34.3% (~107.7 months vs. ~80.2 months) on the same 3000 mAh LiPo. The 51.30 µA / ~83.5-month figures should be considered superseded, not a number to reconcile against.

Acknowledgements

This project was the result of a collaborative engineering effort involving both hands-on experimentation and AI-assisted development. Each AI assistant contributed in different ways throughout the project.

Claude – Lead AI for all aspects of the project. Helped maintain technical focus, reviewed the evolving documentation for clarity and consistency, and provided extensive assistance in coding, organizing, and refining the final Markdown document.
Google Gemini – Provided valuable guidance during the migration to ESP32 Arduino Core 3.3.10, helping identify and avoid legacy code patterns from earlier ESP32 core releases. Gemini also contributed to development discussions involving SX1262 Channel Activity Detection (CAD), Wake-on-Radio (WOR), and ESP32-S3 Deep Sleep integration.
ChatGPT – Assisted throughout firmware development, debugging, architecture discussions, RadioLib integration, power optimization, Nordic PPK2 measurement interpretation, battery-life analysis, and technical review of the final documentation.
GitHub Copilot – Assisted with firmware implementation, code completion, and day-to-day development within the programming environment.
Jan Gromeš – Special thanks for the outstanding RadioLib library!

The successful implementation of an ESP32-S3 Deep Sleeping Wake-on-Radio node using the SX1262 and RadioLib was made possible through this collaborative process. While the hardware design, firmware integration, measurements, testing, and final engineering decisions were performed by the author, the insights provided by each AI assistant significantly accelerated development and helped improve the quality and accuracy of the final project.

"Project not possible without everyone's help."

73's,
William, AB9NQ

RE: ~50 µA ESP-NOW Outside BME280 Node; with LoRa Wake on Radio, part of three node "Heating System Monitor IV"

arvindsa — Sat, 01 Aug 2026 13:30:32 GMT

[mention:f0a26e8d1ffd4be9ba4d4c81332f9c5d:e9ed411860ed4f2ba0265705b8793d05] you seem to be at the lower limit of the current usage. Well done

RE: ~50 µA ESP-NOW Outside BME280 Node; with LoRa Wake on Radio, part of three node "Heating System Monitor IV"

AB9NQ-William — Sat, 01 Aug 2026 13:07:25 GMT

Time is valuable; link to Nordic Power Profiler Observations:

Nordic Power Profiler Kit 2 Observations