I'm trying to make a simple voltage logger using a voltage divider and a ESP32 dev board. The voltage is read and calculated perfectly if that's the only bit in my code, but as soon as I introduce the wifi functionality (WiFiManager.h or ESP8266WiFiMulti.h) any analog pin that I read using analogRead() always returns 4095.
Code follows, any help appreciated!
// LED will blink when in config mode
#include <WiFiManager.h> // https://github.com/tzapu/WiFiManager
//for LED status
#include <Ticker.h>
Ticker ticker;
#ifndef LED_BUILTIN
#define LED_BUILTIN 2 // ESP32 DOES NOT DEFINE LED_BUILTIN
#endif
#define uS_TO_S_FACTOR 1000000
#define TIME_TO_SLEEP 30 //The seconds to sleep
#define BATT_VDIV_PIN 27
int LED = LED_BUILTIN;
void tick()
{
//toggle state
digitalWrite(LED, !digitalRead(LED)); // set pin to the opposite state
}
//gets called when WiFiManager enters configuration mode
void configModeCallback (WiFiManager *myWiFiManager) {
Serial.println("Entered config mode");
Serial.println(WiFi.softAPIP());
//if you used auto generated SSID, print it
Serial.println(myWiFiManager->getConfigPortalSSID());
//entered config mode, make led toggle faster
ticker.attach(0.2, tick);
}
float get_batt_voltage() {
int v=0;
v=analogRead(BATT_VDIV_PIN);
Serial.println(v);
return v;
}
void setup() {
WiFi.mode(WIFI_STA); // explicitly set mode, esp defaults to STA+AP
// put your setup code here, to run once:
Serial.begin(115200);
//set led pin as output
pinMode(LED, OUTPUT);
// start ticker with 0.5 because we start in AP mode and try to connect
ticker.attach(0.6, tick);
//WiFiManager
//Local intialization. Once its business is done, there is no need to keep it around
WiFiManager wm;
//reset settings - for testing
//wm.resetSettings();
//set callback that gets called when connecting to previous WiFi fails, and enters Access Point mode
wm.setAPCallback(configModeCallback);
//fetches ssid and pass and tries to connect
//if it does not connect it starts an access point with the specified name
//here "AutoConnectAP"
//and goes into a blocking loop awaiting configuration
if (!wm.autoConnect()) {
Serial.println("failed to connect and hit timeout");
//reset and try again, or maybe put it to deep sleep
ESP.restart();
delay(1000);
}
//if you get here you have connected to the WiFi
Serial.println("connected...yeey :)");
ticker.detach();
//keep LED on
digitalWrite(LED, LOW);
}
void loop() {
// put your main code here, to run repeatedly:
delay(1000);
Serial.print("Voltage: ");
Serial.println(get_batt_voltage());
}