USB WiFi Power Logger

ina-config.php

<?php
    $mysql_serv = 'localhost';
    $mysql_user = 'usblogger';
    $mysql_pass = 'usblogger';
    $mysql_datb = 'volkszaehler';

    $uuid_v = 1;
    $uuid_a = 2;
?>

ina.php

<?php
    include('ina-config.php');

    if(!isset($_GET['v']) || !isset($_GET['ma'])) die('Invalid request');

    $v = (float)$_GET['v'];
    $mA = (float)$_GET['ma'];

    $uuid = 0;
    $value = 0;

    $sql = new mysqli($mysql_serv, $mysql_user, $mysql_pass, $mysql_datb);
    $stmt = $sql->prepare("INSERT INTO `data` (`id`, `channel_id`, `timestamp`, `value`) VALUES (NULL, ?, UNIX_TIMESTAMP()*1000, ?)");
    $stmt->bind_param("id", $uuid, $value);

    $uuid = $uuid_v;
    $value = $v;
    $stmt->execute();

    $uuid = $uuid_a;
    $value = $mA;
    $stmt->execute();

    $stmt->close();
    $sql->close();

    echo 'OK';
?>

main.cpp

#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_INA219.h>
#include <WiFi.h>
#include <HTTPClient.h>

Adafruit_INA219 ina219;


void setup(void) 
{
  pinMode(LED_BUILTIN, OUTPUT);
  Wire.begin(33, 25);

  Serial.begin(115200);
  while (!Serial) {
      // will pause Zero, Leonardo, etc until serial console opens
      delay(1);
  }
    
  while(millis() < 2000) {
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
    delay(100);
  }
  Serial.println("Hello!");
  
  // Initialize the INA219.
  // By default the initialization will use the largest range (32V, 2A).  However
  // you can call a setCalibration function to change this range (see comments).
  while (! ina219.begin(&Wire)) {
    Serial.println("Failed to find INA219 chip");
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
    delay(1000);
  }
  // To use a slightly lower 32V, 1A range (higher precision on amps):
  //ina219.setCalibration_32V_1A();
  // Or to use a lower 16V, 400mA range (higher precision on volts and amps):
  //ina219.setCalibration_16V_400mA();

  WiFi.begin("freifunk-myk.de", "");
  Serial.println("Connecting");
  while(WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi network with IP Address: ");
  Serial.println(WiFi.localIP());

  Serial.println("Measuring voltage and current with INA219 ...");
}

bool sendHTTP(float loadvoltage, float current_mA) {
  HTTPClient http;
  String url = "http://example.com/ina.php?v=";
  url += loadvoltage;
  url += "&ma=";
  url += current_mA;

  Serial.println(url);

  http.begin(url.c_str());
  int returncode =  http.GET();
  http.end();
  if(returncode == 200) return true;
  return false;
}

void loop(void) 
{
  float shuntvoltage = 0;
  float busvoltage = 0;
  float current_mA = 0;
  float loadvoltage = 0;
  float power_mW = 0;

  shuntvoltage = ina219.getShuntVoltage_mV();
  busvoltage = ina219.getBusVoltage_V();
  current_mA = ina219.getCurrent_mA();
  power_mW = ina219.getPower_mW();
  loadvoltage = busvoltage + (shuntvoltage / 1000);
  
  Serial.print("Bus Voltage:   "); Serial.print(busvoltage); Serial.println(" V");
  Serial.print("Shunt Voltage: "); Serial.print(shuntvoltage); Serial.println(" mV");
  Serial.print("Load Voltage:  "); Serial.print(loadvoltage); Serial.println(" V");
  Serial.print("Current:       "); Serial.print(current_mA); Serial.println(" mA");
  Serial.print("Power:         "); Serial.print(power_mW); Serial.println(" mW");
  Serial.println("");
  
  sendHTTP(loadvoltage, current_mA);
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));

  delay(250);
}

platformio.ini

[env:esp32doit-devkit-v1]
platform = espressif32
board = esp32doit-devkit-v1
framework = arduino
monitor_speed = 115200

lib_deps =
  adafruit/Adafruit INA219 @ ^1.0.9