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Affichage des articles du août, 2016

Garage door sensor with Arduino nano

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 gatewayadd an external sensor and send the status wireless to my 433Mhz to MQTT gatewayOne of these two options with a cableAfter 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 choose solution 2 and build an ex…

Low cost, low power 6uA garden 433Mhz sensor with temperature, humidity ,hygrometer and voltage

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:
waterprooflong battery life, the atmega328p run at 8mhz with minimal components and functionsunder 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 materialThe 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 tubeAt total we are around 10€

PrincipleEvery hour the sensor send the data to a 433Mhz gateway so as to be stored in OpenHAB, the data s…