In this project, we will learn How to design an Accelerometer and Relay based Hand Gesture Controlled Wireless Home Automation System with AVR ATmega32 microcontroller using 433MHz RF. Here, we will use different hand gestures as input signal to control the appliances i.e 2 bulbs and 2 fans. Also, we will display the status of the appliances in a 16X2 alphanumeric LCD.
In our case, hand gestures mean tilt of hand in different direction. To detect different hand gestures, we will use the ADX335 accelerometer sensor. The sensor will be attached to our hand with some material or through a hand glove. The three output signals of accelerometer sensor are analog in nature and it cannot be processed directly by ATmega32 microcontroller. For this, we will use the ADC of the ATmega32 microcontroller to convert the analog signals to digital values. After converting the analog signals of accelerometer sensor to digital values, the ATmega32 microcontroller will process the digital values to find different gestures of the hand. Once the hand gesture is known, the ATmega32 microcontroller will send the required 4 bit signal to the HT12E encoder of RF transmitter circuit. The HT12E will encode the 8 bit address and 4 bit data given to it and then it will transmit the encoded signal serially to the RF module. The RF module will transmit the encoded data and address wirelessly. Also, the microcontroller will display the status of the appliances in a 16X2 alphanumeric LCD.
At the receiver end, the RF receiver module will receive the encoded 4 bit data and 8 bit address. Then, it will transmit the encoded signal serially to the HT12D decoder which will decode the received signal to 8 bit address and 4 bit data. After decoding, the HT12D will compare the received 8 bit address with its local 8 bit address. If the received address and the local address are same, then the received 4 bit data is sent to its output pins else the received data is discarded. The 4 bit output of HT12D is sent to the Quad Relay Driver to turn on and off appliances.
Here, we will use one hand gesture to control one appliance. Same hand gesture will be used to turn on and off the appliance. Each time the same hand gesture is detected, the appliance changes its status. So, for four appliances, we will use 4 different hand gestures. Now, tilt your hand in different direction and control your appliances as you want.