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ESPNOW power management

Aim

To check and test the new connectionless power management features in ESP IDF v5.0.2.

  • Usage: e.config(pm=(window, interval)):

    • every interval milliseconds the radio will be turned on for window milliseconds to listen for incoming messages (interval should be a multiple of 100ms). Incoming messages will be lost while the radio is off. Example:
    e.config(pm=(75, 200))  # equivalent to WLAN.config(pm=WLAN.PM_PERFORMANCE)
e.config(pm=(75, 300))  # equivalent to WLAN.config(pm=WLAN.PM_POWERSAVE)

    See Config ESP-NOW Power-saving Parameter

Based on my micropython espnow-50-pm branch:

Summary of Results (see below for full data)

ESP32: (DFRobot Beetle ESP32 module)

ESPNOW pm setting Duty Cycle Current (mA) Power (mW) % of max
OFF 100% 100 330 100%
pm=(75, 200) 38% 56 185 56%
pm=(75, 300) 25% 47 155 47%
pm=(50, 500) 10% 36 119 36%
pm=(10, 500) 2% 31 102 31%

Radio OFF: Current = 28.9mA (95mW) Radio ON: Current = 100mA (330mW)

ESP32S3: (FeatherS3)

ESPNOW pm setting Duty Cycle Current (mA) Power (mW) % of max
OFF 100% 103 340 100%
pm=(75, 200) 38% 67 221 65%
pm=(75, 300) 25% 57 188 55%
pm=(50, 500) 10% 50 165 49%
pm=(10, 500) 2% 45 149 44%

Radio OFF: Current = 43.8mA (145mW) Radio ON: Current = 104mA (343mW)

ESP32S2: (FeatherS2)

ESPNOW pm setting Duty Cycle Current (mA) Power (mW) % of max
OFF 100% 73 241 100%
pm=(75, 200) 38% 41 135 56%
pm=(75, 300) 25% 35 116 48%
pm=(50, 500) 10% 27 89 37%
pm=(10, 500) 2% 23 76 32%

Radio OFF: Current = 22.2mA (73mW) Radio ON: Current = 73.0mA (241mW)

Software

These measurements are based on my micropython espnow-50-pm branch at:

which includes support for setting the ESPNOW wireless power saving parameters.

Hardware

  • DFRobot Beetle ESP32 module
  • FeatherS3 device from UnexpectedMaker feathers3.io
  • FeatherS2 device from UnexpectedMaker feathers2.io
  • Power Profiler Kit II to measure power consumption of device during experiments.
    • Also supports visualisation of timing pulses from device pins.
  • Cables, computer.

These measurements are made with the PPK2 operating in PSU mode to power the ESP32 devices via the GND and 3.3V pins (some other components will also be powered).

Measurements

Measurements are made with module running the following main.py:

import time, network, espnow

sta = network.WLAN(0)
e = espnow.ESPNow()
sta.active(1); e.active(1)
pm_values = ((75, 200), (75, 300), (50, 500), (10, 500), (1000, 500))
while True:
    for p in pm_values:
        e.config(pm=p)
        time.sleep(2)

DFRobot Beetle ESP32 module

Radio OFF: Current = 28.9mA (95mW) Radio ON: Current = 100mA (330mW)

ESPNOW pm setting Average Current (mA) PPK2 Screenshot
pm=(1000, 500) (disabled) 100 _
pm=(75, 200) 56 _
pm=(75, 300) 47 _
pm=(50, 500) 36 _
pm=(10, 500) 31 _

FeatherS3 module

Radio OFF: Current = 43.8mA (145mW) Radio ON: Current = 104mA (343mW)

ESPNOW pm setting Average Current (mA) PPK2 Screenshot
pm=(1000, 500) (disabled) 103 _
pm=(75, 200) 67 _
pm=(75, 300) 57 _
pm=(50, 500) 50 _
pm=(10, 500) 45 _