diff --git a/cocomobile-arduino/cocomobile-arduino.ino b/cocomobile-arduino/cocomobile-arduino.ino
index 1981537..122c281 100644
--- a/cocomobile-arduino/cocomobile-arduino.ino
+++ b/cocomobile-arduino/cocomobile-arduino.ino
@@ -8,7 +8,7 @@ SoftwareSerial lora(8, 9); // RX, TX
 float tens = 0;
 float amp = 0;
 
-String line;
+String line = "";
 
 void setup() {
   lora.begin(9600);
diff --git a/receive-arduino/receive-arduino.ino b/receive-arduino/receive-arduino.ino
index 0849cbf..2140845 100644
--- a/receive-arduino/receive-arduino.ino
+++ b/receive-arduino/receive-arduino.ino
@@ -4,7 +4,7 @@ SoftwareSerial lora(8, 9); // RX, TX
 
 bool test_with_fake = false;
 
-String line;
+String line = "";
 
 void setup() {
   Serial.begin(115200);