1 Technophile

I needed to have a way to know the state of my garage door.  Several solutions where at my disposal so as to do that; hack the existing control central to be able to know the position of the door and send the status wireless to my 433Mhz to MQTT gateway add an external sensor  and send the status wireless to my  433Mhz to MQTT gateway One of these two options with a cable After some investigations on the control central of my garage door I have deducted that there is no "closed" "open" contact, indeed the stop of the motor seems to be detected by the fact that it is "forcing" maybe by detecting some over current. The sensor that I have at the bottom of this garage door is in case there is an obstacle in the course of the door. Sending a stop to the motor. Unfortunately I can't use this due to the fact it is not actionned at the end of the course. Safety sensor of the garage door (cannot be hacked for state recognition) I had to ...

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€ ...