1 Technophile

Following my first build of an external garden sensor, here is a simplified version with temperature, humidity and battery voltage measurement for a baby bedroom [EDIT] feedback about the expected battery duration here The requirements are: cheap long battery life, the atmega328p run at 8mhz with minimal components and functions under 8€ wireless (433Mhz) with good range (2 walls to cross and 10 meters) Here is the final view attached to a lion for decoration: And a report from OpenHab displaying the sensor data: If you want more details about energy power consumption the first article on this subject is more detailled. Now let's see how to build this. Bill of material The sensors is based on atmega328p (3€),  a 433 Mhz transmitter (1,5€) , a DHT22 temperature and humidity sensor (4€), a 433 mhz antenna (0,18€) DIP socket adaptor for the ATmega (1€) an electronic prototype printed circuit board (0,5€) At total we...

I have built an external sensor so as to monitor temperature, air humidity, soil humidity of my garden and the battery voltage. The requirements was: waterproof long battery life, the atmega328p run at 8mhz with minimal components and functions under 10€ wireless (433Mhz) with good range (2 walls to cross and 10 meters) Here is the final view: And some reports from OpenHab displaying the sensor data: Air humidity Soil humidity Air temperature We can of course imagine to use these values to control a water pump. Now let's see hpw to build this. Bill of material The sensors is based on atmega328p (3€),  a 433 Mhz transmitter (1,5€) , a DHT11 (1€) or a DHT22 temperature and humidity sensor, a soil moisture sensor  (1,6€), an electrical box (1€)  a 433 mhz antenna (0,18€) DIP socket adaptor for the ATmega (1€) an electronic prototype printed circuit board (0,5€) a recycled  tube At total we are around 10€ ...