RadioPower - WiFi radio power controls

Layer: L7 Application · Build flags: PROTOCORE_ENABLE_RADIO_POWER (+ PROTOCORE_RADIO_WIFI_PS, optional PROTOCORE_RADIO_MAX_TX_DBM)

What this example teaches

On a battery device the WiFi radio dominates the power budget. This applies a WiFi modem-sleep mode (and an optional max-TX-power cap) after the link comes up, trading a little latency for lower average current. GET /radio reports the mode read back from the radio.

Apply after the link is up. The WiFi connect path may set its own default first, so the settings are applied once association completes:

Radio.power();   // applies the build-flag-configured modem-sleep / TX cap
Serial.printf("radio modem-sleep: %s\n", Radio.ps_name(Radio.ps_mode()));

The mode is a build flag, not a runtime call, so it reaches the separately-compiled library: PROTOCORE_RADIO_WIFI_PS is 0 (none), 1 (min modem sleep), or 2 (max modem sleep), with an optional PROTOCORE_RADIO_MAX_TX_DBM cap. Radio.ps_mode() reads the live mode back and Radio.ps_name() turns it into a string for the endpoint.

Build and run

pio ci --board=esp32dev --project-option="framework=arduino" \
  --project-option="build_flags=-DPROTOCORE_ENABLE_RADIO_POWER=1 -DPROTOCORE_RADIO_WIFI_PS=1" \
  --lib="." examples/L7-Application/RadioPower/RadioPower.ino

curl http://<ip>/radio   # {"modem_sleep":"min"}

Annotated source

The complete sketch (RadioPower.ino), reproduced verbatim with added explanatory comments:

// Copyright (C) 2026 Douglas Quigg (dstroy0) <dquigg123@gmail.com>
// SPDX-License-Identifier: AGPL-3.0-or-later
 
#define PROTOCORE_ENABLE_RADIO_POWER 1
 
#include "protocore.h"
#include "network_drivers/physical/physical/physical.h"
#include "network_drivers/physical/radio_power/radio_power.h"
 
static const char *SSID = "YOUR_SSID";
static const char *PASSWORD = "YOUR_PASSWORD";
 
PC server;
 
void setup()
{
    Serial.begin(115200);
    Physical.wifi->init(SSID, PASSWORD);
    while (!Physical.wifi->ready())
        delay(250);
    Serial.print("IP: ");
    uint32_t ip = Physical.link->egress_ip(); // library egress IP (network byte order), no Arduino WiFi
    Serial.printf("IP: %u.%u.%u.%u\n", (unsigned)(ip & 0xFF), (unsigned)((ip >> 8) & 0xFF),
                  (unsigned)((ip >> 16) & 0xFF), (unsigned)((ip >> 24) & 0xFF));
 
    // Apply the configured modem-sleep / TX settings AFTER the link is up (the
    // WiFi connect path may set its own default first).
    Radio.power();
    Serial.printf("radio modem-sleep: %s\n", Radio.ps_name(Radio.ps_mode()));
 
    server.on("/radio", HttpMethod::HTTP_GET, [](uint8_t id, HttpReq *) {
        char b[48];
        snprintf(b, sizeof(b), "{\"modem_sleep\":\"%s\"}", Radio.ps_name(Radio.ps_mode()));
        server.send(id, 200, "application/json", b);
    });
    server.begin(80);
}
 
void loop()
{
    server.handle();
}