diff --git a/firmware/Makefile b/firmware/Makefile
index 314a301..4c3776b 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -3,6 +3,7 @@ CFLAGS += -save-temps
 CFLAGS += -std=gnu99 -Wall # implements C99, for <util/atomic.h>
 # this removes dead code and does global linker optimization
 #CFLAGS += -ffunction-sections -Wl,--gc-sections -Wl,--relax 
+CFLAGS += -Lm
 
 
 include Makefile.inc
diff --git a/firmware/slavechip/main.c b/firmware/slavechip/main.c
index 4f62cab..f403b97 100644
--- a/firmware/slavechip/main.c
+++ b/firmware/slavechip/main.c
@@ -3,8 +3,8 @@
 #include "muxer.h"
 #include "i2c_simple.h"
 #include "mcp_adc.h"
-
 #include "debug.h"
+#include "math.h"
 
 uint16_t timertmp;
 uint16_t temperatures[4];
@@ -30,8 +30,61 @@ int16_t temp_avg_count[4];
 #define MUXER_CHANNEL_3 3
 
 
-uint16_t calc_temp(uint16_t val) {
-	// TODO: implement polygon ... wait, no, polyester, uh, no again? ... poly-thingy?
+int32_t avg_temp(int16_t val, uint8_t channel) {
+	int32_t temp = temp_avg_cumul[channel];
+	temp /= temp_avg_count[channel];
+	temp_avg_count[channel] = 0;
+	temp_avg_cumul[channel] = 0;
+	return (temp * 625); // nV
+}
+
+uint16_t calc_temp(int16_t val, uint8_t channel) {
+	float mV =  ((float) avg_temp(val, channel))/1000000;
+	uint16_t temp;
+	if(mV < 0) {
+		/* t in mV
+		E = sum(i=0 to n) c_i t^i.		; n=10
+		*/
+		float coef[] = {
+			0.000000000000E+00,
+			0.394501280250E-01,
+			0.236223735980E-04,
+			-0.328589067840E-06,
+			-0.499048287770E-08,
+			-0.675090591730E-10,
+			-0.574103274280E-12,
+			-0.310888728940E-14,
+			-0.104516093650E-16,
+			-0.198892668780E-19,
+			-0.163226974860E-22
+		};
+		for(int i=0; i<11; i++) {
+			temp += coef[i] * pow(mV, i+1);
+		}
+		return temp;
+	} else {
+		/*
+		  t in mV
+		  E = sum(i=0 to n) c_i t^i + a0 exp(a1 (t - a2)^2).     ; n = 9
+		 */
+		float coef[] = {
+			-0.176004136860E-01,
+			0.389212049750E-01,
+			0.185587700320E-04,
+			-0.994575928740E-07,
+			0.318409457190E-09,
+			-0.560728448890E-12,
+			0.560750590590E-15,
+			-0.320207200030E-18,
+			0.971511471520E-22,
+			-0.121047212750E-25
+		};
+		float a[] = {0.118597600000E+00, -0.118343200000E-03, 0.126968600000E+03};
+		for(int i=0; i<10; i++) {
+			temp += coef[i]*pow(mV, i+1) + a[0] * pow(exp(a[1]*(mV - a[2])), 2);
+		}
+		
+	}
 }
 
 /* initializes the hardware */
@@ -65,7 +118,7 @@ int __attribute__((noreturn)) main(void) {
     SOFTTIMER(1,10) {
 		for(int i=0; i<4; i++) {
 			if(sensor_active[i] && mcpadc_has_new_data(i)) {
-				temperatures[i] = calc_temp( mcpadc_get_data(i) );
+				temperatures[i] = calc_temp( mcpadc_get_data(i), i );
 				temp_avg_cumul[i] += temperatures[i];
 				temp_avg_count[i] += 1;
 			}