diff --git a/lambda-test/Makefile b/lambda-test/Makefile
index d5fcefd..a533629 100644
--- a/lambda-test/Makefile
+++ b/lambda-test/Makefile
@@ -28,7 +28,7 @@
 
 PROGRAMMER_TYPE = avrisp
 # extra arguments to avrdude: baud rate, chip type, -F flag, etc.
-PROGRAMMER_ARGS = -b 19200 -P /dev/ttyACM3
+PROGRAMMER_ARGS = -b 19200 -P /dev/ttyACM0
 
 ##########------------------------------------------------------##########
 ##########                   Makefile Magic!                    ##########
diff --git a/lambda/Makefile b/lambda/Makefile
index 9b58805..5eee898 100644
--- a/lambda/Makefile
+++ b/lambda/Makefile
@@ -28,7 +28,7 @@
 
 PROGRAMMER_TYPE = avrisp
 # extra arguments to avrdude: baud rate, chip type, -F flag, etc.
-PROGRAMMER_ARGS = -b 19200 -P /dev/ttyACM3
+PROGRAMMER_ARGS = -b 19200 -P /dev/ttyACM0
 
 ##########------------------------------------------------------##########
 ##########                   Makefile Magic!                    ##########
diff --git a/lambda/adc.c b/lambda/adc.c
index 2153a46..b584902 100644
--- a/lambda/adc.c
+++ b/lambda/adc.c
@@ -30,13 +30,7 @@
  */
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
-
-// TODO right place for these definitions? Put in makefile?
-// #define AREF_MV 4850
-#define AREF_MV 5000
-#define ADC_OFFSET_MV 7
-// #define TEMPO_OP_OFFSET_MV 441
-#define TEMPO_OP_OFFSET_MV 454
+#include "adc.h"
 
 // TODO what exactly does this do?
 EMPTY_INTERRUPT(ADC_vect);
diff --git a/lambda/adc.h b/lambda/adc.h
index cf04254..014329e 100644
--- a/lambda/adc.h
+++ b/lambda/adc.h
@@ -29,6 +29,13 @@
  * started with AVR programming.
  */
 
+// TODO Put in makefile
+// #define AREF_MV 4850
+#define AREF_MV 5000
+#define ADC_OFFSET_MV 7
+// #define TEMPO_OP_OFFSET_MV 441
+#define TEMPO_OP_OFFSET_MV 454
+
 /**
  * Sets up reference voltage and clock prescaler of the ADC and enables it.
  */
diff --git a/lambda/sensors.c b/lambda/sensors.c
index addd559..ae09abd 100644
--- a/lambda/sensors.c
+++ b/lambda/sensors.c
@@ -94,7 +94,7 @@
 	tempOVoltageAvg = average(tempOVoltage, tempOVoltageAvg, 4);
 
 	// OP factor is 11
-	int16_t lambdaVoltage = (getVoltage(PC2) + 5) / 11;
+	int16_t lambdaVoltage = divRoundNearest(getVoltage(PC2), 11);
 	lambdaVoltageAvg = average(lambdaVoltage, lambdaVoltageAvg, 4);
 
 	int16_t tempI = toTempI(tempIVoltageAvg);