diff --git a/lambda-test/lambda-test.c b/lambda-test/lambda-test.c
index d0f7847..d3cb2ff 100644
--- a/lambda-test/lambda-test.c
+++ b/lambda-test/lambda-test.c
@@ -56,6 +56,9 @@
 
 	// AVCC is set as AREF
 	if ((ADMUX & (1 << REFS0)) != (1 << REFS0)) return false;
+	// digital inputs are disabled
+	uint8_t adcPorts = (1 << PC0) | (1 << PC2) | (1 << PC5);
+	if ((DIDR0 & adcPorts) != adcPorts) return false;
 	// ADC clock prescaler/8
 	uint8_t prescalerBy8 = (1 << ADPS1) | (1 << ADPS0);
 	if ((ADCSRA & prescalerBy8) != prescalerBy8) return false;
diff --git a/lambda/adc.c b/lambda/adc.c
index 73ababe..ae4a7d3 100644
--- a/lambda/adc.c
+++ b/lambda/adc.c
@@ -35,6 +35,9 @@
 void setupADC(void) {
 	// use AVCC as reference voltage
 	ADMUX |= (1 << REFS0);
+	// disable digital input on the ADC inputs
+	// http://www.openmusiclabs.com/learning/digital/atmega-adc/
+	DIDR0 |= (1 << PC0) | (1 << PC2) | (1 << PC5);
 	// ADC clock prescaler/8
 	ADCSRA |= (1 << ADPS1) | (1 << ADPS0);
 	// enable ADC
diff --git a/lambda/lambda.c b/lambda/lambda.c
index 064d218..d337458 100644
--- a/lambda/lambda.c
+++ b/lambda/lambda.c
@@ -34,6 +34,7 @@
 
 #include <stdio.h>
 #include <util/delay.h>
+#include <avr/io.h>
 #include "USART.h"
 #include "adc.h"
 #include "sensors.h"
@@ -53,10 +54,6 @@
 	setupADC();
 	setupSleepMode();
 
-	// disable digital input on ADC0
-	// http://www.openmusiclabs.com/learning/digital/atmega-adc/
-	// DIDR0 = 0b00000011;
-
 	// main loop
 	while (1) {
 		measurement meas = measure();