 #include <ESP8266HTTPClient.h>
 #include <WiFiClientSecureBearSSL.h>
 
+// Base URL for HTTP GET requests.
 String kBaseUrl = "https://docs.google.com/forms/d/e/YOUR_SPREADSHEET_ID/formResponse?entry.ENTRY_CODE=";
-// Client fingerprint, to generate, use:
-//   openssl s_client -connect docs.google.com:443 < /dev/null 2>/dev/null | openssl x509 -fingerprint -noout -in /dev/stdin
-constexpr char kFingerprint[] = "5B:E1:DA:24:FE:99:92:FB:D2:AB:A8:DD:E9:49:AF:3A:56:43:F1:B4";
+// WiFi SSID and password.
 constexpr char kApSsid[] = "YOUR_SSID";
 constexpr char kApPassword[] = "";
+// Pin to read meter pulse.
 constexpr int kPin = 5;
+// Debounce delay.
+constexpr uint32_t kDebounceDelayMs = 50;
 
 ESP8266WiFiMulti WiFiMulti;
 
 int pulse_count = 0;
 int previous_state = LOW;
 int current_state;
-unsigned long previous_debounce_ms = 0;
-constexpr unsigned long kDebounceDelayMs = 50;
+uint32_t previous_debounce_ms = 0;
 
 void setup() {
   pinMode(kPin, INPUT_PULLUP);

  Serial.println();
  Serial.println();

  for (uint8_t t = 4; t > 0; t--) {
    Serial.printf("[SETUP] WAIT %d...\n", t);
    Serial.flush();
    delay(1000);
  }

  WiFi.mode(WIFI_STA);
  WiFiMulti.addAP(kApSsid, kApPassword);

          }
          https.end();
        } else {
          Serial.println("Connection failed.");
        }
      }
    }
