3.2.15 The specification of DHT22 temperature sensor:
digital signal via single-bus
humidity 0-100%RH; temperature -40~80Celsius
humidity +-2%RH(Max +-5%RH); temperature <+-0.5Celsius Resolution or sensitivity humidity 0.1%RH; temperature 0.1Celsius Repeatability humidity +-1%RH; temperature +-0.2Celsius Humidity hysteresis +-0.3%RH Long-term Stability +-0.5%RH/year Sensing period Average: 2s Interchangeability fully interchangeable Dimensions small size 14*18*5.5mm; big size 22*28*5mm Method: Firstly set up raspberry pi with Raspbian operating system. The operating system download on the official raspberry pi website. Then the operating system burn to SD disc. The disc is placed on the raspberry pi. Then power is connected on the pi. Then install Adafruit library on pi terminal. Download putty software to connect lap top onto the pi and also install Xming software for using the laptop display as the pi display. Now the raspberry pi connect to the local Wi-Fi network. Use advance IP scanner to find the ip address of pi. Then using this ip address to connect the pi using the putty and xming software. Then it connect the cayenne Iot server. IOT dashboard Cayenne by my-Devices is totally free online builder they do not yet make it paid services because they working on it to make more reliable and stable when they release stable version may we have to pay for this cloud service, Currently in Raspberry pi version which has Lil bit bugs but not too worried about final version they will make it bugles online portal. Feature of Cayenne-My Device IOT Dashboard: Remotely access Pi from Mobile and PC. Reboot, Shutdown Pi Remotely. add sensors , actuator, extensions, and design dashboard for Raspberry pi add widgets with drag and drop feature Remotely monitor live data from sensors and actuator. Control sensors/actuator with dashboard GPIO. Best thing is that for you Automation Projects you can make the trigger and add the schedule. Let's start how it is work with Raspberry pi Configuration of Cayenne Raspberry for Home Automation Cayenne is IOT based dashboard so you need hardware which can be connected to the internet for this purpose you need Raspberry Wi-Fi or Ethernet Shield. The important thing is how to configure Cayenne IOT dashboard for Raspberry pi I make this guide step by step to understand easily who not know much about IOT but want to learn. Step 1: First of all, you need a working internet connection then create a free account on Cayenne. Step 2: After completion of creating the account you have to choose Raspberry Pi board Step 3: After this now in step 3 we have to work on Raspberry Pi side first thing need Python IDE latest version installed on the computer if it do not have then download from internet and also need to install Cayenne Library for Raspberry Pi. Connect Raspberry Pi with USB cable to the computer and configure properly Step 4: Back to Cayenne Dashboard Select your board and Shield after that, a popup appear with Code for Raspberry pi copy it and upload it to your board with Raspberry Pi tool. After uploading, code connects Raspberry Pi with the internet. When you correctly did everything Cayenne Automatically detect Raspberry Pi. Cayenne Raspberry Pi Dashboard Settings Now i add Sensors/Actuators. First, create project give name to it now i add sensors/actuators according to my project. In this project, I used PIR sensor to control home security alert and control home appliance with the relay module. Now select Relay Actuator and add eight relay actuators/button one for the home appliance and second for PIR sensor and added another device to show temperature and humidity to cayenne dashboard. When you added sensor and relays you need to configure each which you connected on Raspberry Pi on which pin Digital/Analog. See below images how I Figure: Raspberry pi GPIO pins Diagram Configure you can also use invert logic in setting of any sensors/actuators. Invert Logic can be used to reverse the high/low signal. The most common use of this is with a LED: if the button on the dashboard turns the light on when it should be turning it off, clicking "invert logic" will reverse the signal to correct the problem. Now added Trigger go to sensor settings and select trigger option. Cayenne IOT dashboard also has a feature to schedule your sensors/actuator and also I add a trigger for notifying when the Light on and off. I can get notification via Email and SMS. I can control and manage my project from Mobile app and PC 3.2.12 Smart home automation system This application of the module can be explained by an example. Suppose the owner is expecting a guest at his house but he is not available there. Now, as the guests reach at his house the owner will receive a video call. But now the owner can press digits other than 1 (such as 3 for lights, 4 for fan, 5 for A.C., and so on) or even can disable the security system. Similarly if the user or somebody leaves the house, the user Will still receive a video call and this time he can switch off the appliances or can enable the security system again by pressing proper digits known to him. Since the appliances are connected to mains supply through a relay they can be easily controlled using micro-controller. 4.1 Result and Discussion: Both, the Raspberry Pi and the mobile application, are senders and receivers of data. This applies as both publish and subscribe at the same time to the same cayenne IOT server. This allowed bi-directional communication for data exchange. Accordingly, multiple use cases were implemented and studied for result analysis. 4.1.1 Home appliance control The Light, Fan and other home appliance are connected to the Raspberry Pi through the GPIO pins and embedded in the model, were controlled through a mobile application developed with Ionic. A "Light" tab was created in the application which has a button that toggles between "ON" and "OFF" when clicked. The default value of the button shows the current status of the LED lights. If the button shows the value "OFF", this means that the LEDs are currently turned off.