diff --git a/lambda/interrupts.c b/lambda/interrupts.c
index 5ae97e6..c6627ce 100644
--- a/lambda/interrupts.c
+++ b/lambda/interrupts.c
@@ -5,9 +5,81 @@
  *      Author: dode@luniks.net
  */
 
+#include <stdbool.h>
+#include <string.h>
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
 #include "interrupts.h"
+#include "sensors.h"
+#include "display.h"
+#include "alert.h"
+
+volatile bool buttonPressed = false;
+volatile bool usartReceived = false;
+volatile uint8_t intCount = 0;
+
+char usartData[64];
+
+/**
+ * Called every 16 ms.
+ */
+ISR(TIMER0_OVF_vect) {
+	intCount++;
+	oscillateBeep();
+	if (bit_is_clear(PINB, PB0) && ! buttonPressed) {
+		buttonPressed = true;
+		cycleDisplay();
+	} else if (bit_is_set(PINB, PB0)) {
+		buttonPressed = false;
+	}
+}
+
+/**
+ * Called when data was received via USART.
+ */
+ISR(USART_RX_vect) {
+	if (bit_is_set(UCSR0A, RXC0) && ! usartReceived) {
+		char data = UDR0;
+		uint8_t length = strlen(usartData);
+		if (length < sizeof(usartData) - 1 && data != '\n' && data != '\r') {
+			usartData[length] = data;
+		} else {
+			usartData[length] = '\0';
+			usartReceived = true;
+		}
+	}
+}
+
+// TODO doesn't really belong in this source file
+bool isButtonPressed(void) {
+	return buttonPressed;
+}
+
+// TODO doesn't really belong in this source file
+bool isUSARTReceived(void) {
+	return usartReceived;
+}
+
+// TODO doesn't really belong in this source file
+void getUSARTData(char* data, uint8_t size) {
+	if (size > 0) {
+	    data[0] = '\0';
+	    strncat(data, usartData, size - 1);
+	}
+	memset(usartData, 0, sizeof(usartData));
+	usartReceived = false;
+}
+
+bool hasIntCount(uint8_t count, bool reset) {
+	if (intCount >= count) {
+		if (reset) {
+			intCount = 0;
+		}
+		return true;
+	} else {
+		return false;
+	}
+}
 
 void setupPorts(void) {
 	// pull-up resistor for the mouton
@@ -31,7 +103,7 @@
 	TIMSK0 |= (1 << TOIE0);
 
 	// enable USART RX complete interrupt 0
-	// UCSR0B |= (1 << RXCIE0);
+	UCSR0B |= (1 << RXCIE0);
 	// enable data register empty interrupt 0
 	// UCSR0B |= (1 << UDRIE0);
 
diff --git a/lambda/interrupts.h b/lambda/interrupts.h
index 11efa34..4fafbbf 100644
--- a/lambda/interrupts.h
+++ b/lambda/interrupts.h
@@ -8,6 +8,14 @@
 #ifndef INTERRUPTS_H_
 #define INTERRUPTS_H_
 
+bool isButtonPressed(void);
+
+bool isUSARTReceived(void);
+
+void getUSARTData(char*, uint8_t);
+
+bool hasIntCount(uint8_t count, bool reset);
+
 /**
  * Sets up ports.
  */
diff --git a/lambda/lambda.c b/lambda/lambda.c
index 570cd3a..78f3e68 100644
--- a/lambda/lambda.c
+++ b/lambda/lambda.c
@@ -27,47 +27,10 @@
 #include "adc.h"
 #include "interrupts.h"
 #include "sensors.h"
-#include "integers.h"
 #include "display.h"
 #include "alert.h"
 #include "command.h"
 
-volatile bool buttonPressed = false;
-volatile bool usartReceived = false;
-volatile uint8_t intCount = 0;
-volatile uint8_t dataCount = 0;
-
-char usartData[64];
-
-/**
- * Called every 16 ms.
- */
-ISR(TIMER0_OVF_vect) {
-	intCount++;
-	oscillateBeep();
-	if (bit_is_clear(PINB, PB0) && ! buttonPressed) {
-		buttonPressed = true;
-		cycleDisplay();
-	} else if (bit_is_set(PINB, PB0)) {
-		buttonPressed = false;
-	}
-}
-
-/**
- * Called when data was received via USART.
- */
-ISR(USART_RX_vect) {
-	if (bit_is_set(UCSR0A, RXC0) && ! usartReceived) {
-		char data = UDR0;
-		if (dataCount < sizeof(usartData) - 1 && data != '\n' && data != '\r') {
-			usartData[dataCount++] = data;
-		} else {
-			usartData[dataCount++] = 0;
-			usartReceived = true;
-		}
-	}
-}
-
 /**
  * Does initialization and measures, displays and logs the measurements
  * infinitely.
@@ -87,23 +50,21 @@
 
 	// main loop
 	while (1) {
-		if (intCount >= 62 && ! isSimulation()) {
-			intCount = 0;
+		if (hasIntCount(62, true) && ! isSimulation()) {
 			meas = measure();
 			if (isLogging()) {
 				printMeas(meas);
 			}
 			updateMeas(meas);
 		}
-		if (buttonPressed) {
+		if (isButtonPressed()) {
 			// update display immediately
 			updateMeas(meas);
 		}
-		if (usartReceived) {
-			command(usartData);
-			memset(usartData, 0, sizeof(usartData));
-			dataCount = 0;
-			usartReceived = false;
+		if (isUSARTReceived()) {
+			char data[64];
+			getUSARTData(data, sizeof(data));
+			command(data);
 		}
 	}