diff --git a/.gitignore b/.gitignore
index 427a91e..1d862d4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,6 @@
 bme680
 bme680_i2c
 bme680_spi
-bme680_log*
\ No newline at end of file
+bme680_log*
+plot/*.png
+plot/*.txt
\ No newline at end of file
diff --git a/README.md b/README.md
index 9f0b960..9ffadce 100644
--- a/README.md
+++ b/README.md
@@ -106,8 +106,6 @@ gas resistance: 14702.868852 Ohm
 === heat_stab_r: 1
 ```
 
-Note: Do not trust the gas resistance measurement if `heat_stab_r` is not `1`.
-
 ## Burn-in / logging
 
 See file `example/log.c` 
@@ -119,64 +117,9 @@ See file `example/log.c`
 
 Compile and run
 ```sh
-stdbuf -o0 ./bme680 2>&1 | tee -a log.txt
-```
-
-This will give an output similar to this:
-```
-2024-05-14T13:03:02+0100 20.8916 99836.7 68.6594 7180.73 1
-2024-05-14T13:04:03+0100 20.8658 99840.3 68.7844 7171.53 1
-2024-05-14T13:05:03+0100 20.8979 99838.6 68.7759 7162.35 1
-2024-05-14T13:06:03+0100 20.9208 99843.8 68.6436 7166.93 1
-2024-05-14T13:07:03+0100 20.9303 99845.4 68.747 7144.05 1
-2024-05-14T13:08:03+0100 20.9249 99846 68.7122 7139.49 0
-2024-05-14T13:09:04+0100 20.9036 99845.2 68.7224 7157.76 1
-2024-05-14T13:10:04+0100 20.8737 99850.5 68.575 7144.05 1
-2024-05-14T13:11:04+0100 20.8753 99850.6 68.8879 7139.49 1
-2024-05-14T13:12:04+0100 20.9152 99849.3 68.8602 7134.94 1
-```
-
-If last field is not 1 then the measurement, at least for gas resistance, cannot be trusted.
-```sh
-sed -n '/1$/p' log.txt > test.txt
-```
-
-Then graph with gnuplot
-```
-# gnuplot
-reset
-
-set key autotitle columnhead
-set terminal pngcairo enhanced size 2*1920/3,2*1080/3
-set grid
-set xdata time
-set timefmt "%Y-%m-%dT%H:%M:%S%z"
-
-
-
-# gas res vs time 
-set title "[I_{dac}=100, 100ms, target=300 C] GasRes over time"
-set xlabel "Time"
-set ylabel "Gas Resistance (OHM)"
-set output "gas.png"
-plot 'test.txt' u 1:5 w p pt 3 ps 1 t "BME680"
-
-
-set title "[I_{dac}=100, 100ms, target=300 C] Temperature over time"
-set xlabel "Time"
-set ylabel "Temperature (C)"
-set output "temp.png"
-plot 'test.txt' u 1:2 w p pt 3 ps 1 t "BME680"
-
-set title "[I_{dac}=100, 100ms, target=300 C] Pressure over time"
-set xlabel "Time"
-set ylabel "Pressure (Pa)"
-set output "press.png"
-plot 'test.txt' u 1:3 w p pt 3 ps 1 t "BME680"
-
-set title "[I_{dac}=100, 100ms, target=300 C] Humidity over time"
-set xlabel "Time"
-set ylabel "Humidity (%RH)"
-set output "hum.png"
-plot 'test.txt' u 1:4 w p pt 3 ps 1 t "BME680"
+$ stdbuf -o0 ./bme680_log_i2c 2>&1 | tee -a data/i2c.txt &
+$ stdbuf -o0 ./bme680_log_spi 2>&1 | tee -a data/spi.txt &
+# wait a couple of hours or days ..
+$ cd plot
+$ ./plot.sh
 ```
diff --git a/plot/gnuplot.gpt b/plot/gnuplot.gpt
new file mode 100644
index 0000000..7d95040
--- /dev/null
+++ b/plot/gnuplot.gpt
@@ -0,0 +1,37 @@
+# gnuplot
+reset
+
+set key autotitle columnhead
+set terminal pngcairo enhanced size 2*1920/3,2*1080/3
+set grid
+set xdata time
+set timefmt "%Y-%m-%dT%H:%M:%S%z"
+
+# gas res vs time 
+set title "[I_{dac}=100, 100ms, target=300 C] GasRes over time"
+set xlabel "Time"
+set ylabel "Gas Resistance (OHM)"
+set output "gas.png"
+plot 'i2c.txt' u 1:5 w p pt 3 ps 1 t "bme680-i2c", \
+     'spi.txt' u 1:5 w p pt 3 ps 1 t "bme680-spi"
+
+set title "[I_{dac}=100, 100ms, target=300 C] Temperature over time"
+set xlabel "Time"
+set ylabel "Temperature (C)"
+set output "temp.png"
+plot 'i2c.txt' u 1:2 w p pt 3 ps 1 t "bme680-i2c", \
+     'spi.txt' u 1:2 w p pt 3 ps 1 t "bme680-spi"
+
+set title "[I_{dac}=100, 100ms, target=300 C] Pressure over time"
+set xlabel "Time"
+set ylabel "Pressure (Pa)"
+set output "press.png"
+plot 'i2c.txt' u 1:3 w p pt 3 ps 1 t "bme680-i2c", \
+     'spi.txt' u 1:3 w p pt 3 ps 1 t "bme680-spi"
+
+set title "[I_{dac}=100, 100ms, target=300 C] Humidity over time"
+set xlabel "Time"
+set ylabel "Humidity (%RH)"
+set output "hum.png"
+plot 'i2c.txt' u 1:4 w p pt 3 ps 1 t "bme680-i2c", \
+     'spi.txt' u 1:4 w p pt 3 ps 1 t "bme680-spi"
\ No newline at end of file
diff --git a/plot/plot.sh b/plot/plot.sh
new file mode 100755
index 0000000..77ba9ab
--- /dev/null
+++ b/plot/plot.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+
+sed -n '/1$/p' ../data/spi.txt > spi.txt
+sed -n '/1$/p' ../data/i2c.txt > i2c.txt
+gnuplot gnuplot.gpt
\ No newline at end of file