diff --git a/README.md b/README.md
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+++ b/README.md
@@ -8,6 +8,7 @@
 - embedded systems : https://en.wikibooks.org/wiki/Embedded_Systems/Atmel_AVR
 - timers for newbies : https://qiriro.com/bme6163/static_files/notes/L3/Newbie%27s%20Guide%20to%20AVR%20Timers.pdf
 - timer and pwm : https://wolles-elektronikkiste.de/en/timer-and-pwm-part-2-16-bit-timer1
+- doc AHT20 thermostat : https://asairsensors.com/wp-content/uploads/2021/09/Data-Sheet-AHT20-Humidity-and-Temperature-Sensor-ASAIR-V1.0.03.pdf
 
 ## m00ex00
 
diff --git a/ressources/Data-Sheet-AHT20-Humidity-and-Temperature-Sensor-ASAIR-V1.0.03.pdf b/ressources/Data-Sheet-AHT20-Humidity-and-Temperature-Sensor-ASAIR-V1.0.03.pdf
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