diff --git a/answers/lesson04/lesson04.ino b/answers/lesson04/lesson04.ino
index 48d36e4..702dc46 100644
--- a/answers/lesson04/lesson04.ino
+++ b/answers/lesson04/lesson04.ino
@@ -19,7 +19,7 @@ int sensorValue = 0;
 
 void setup() {
   Serial.begin(115200);
-  pinMode(A0, INPUT);
+  pinMode(MOISTURE_PIN, INPUT);
 
   WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
   Serial.print("connecting");