INTRODUCTION Gesture recognition enables humans to communicate with the machine and interact naturally without any mechanical devices. These gestures can originate from any bodily motion or state but commonly originate from the face or hand. In this project we have tried to control a robot by hand gestures using an accelerometer sensor in conjunction with a MCU and RF link.
RF Link 434 MHz HT12E Decoder IC Accelerometer ADLX335 100 rpm DC motors HT12D Encoder IC MCU Atmega16 Voltage regulator (7805) Voltage regulator (7805) Motor Driver (L293D) Motor Driver (L293D)
Components Specifications Accelerometer Sensor The ADXL335 is a small, thin, complete 3-axis accelerometer. It measures acceleration with a minimum full-scale range of ±3 g. It is can be used in the static as well as dynamic applications.
Components Specifications RF Link 434 MHz This RF link comprises of an RF Transmitter and an RF Receiver. The (Tx/Rx) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4. The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.
Components Specifications HT12E Encoder IC HT12E is an encoder integrated circuit of 212 series of encoders. It encodes the 12 bit parallel data into serial for transmission through an RF transmitter. These 12 bits are divided into 8 address bit s and 4 data bits.
Components Specifications HT12D Decoder IC It is a decoder integrated circuit that belongs to 212 series of decoders. It is capable of decoding 12 bits, of which 8 are address bits and 4 are data bits. The data on 4 bit latch type output pins remain unchanged until new is received.
Components Specifications 100 rpm DC motors It is a low cost DC motor suitable for most robotic and general applications. It has a output shaft with a hole for easy mounting of wheels or pulleys. Input Voltage: 6-12 V Stall Current: 500 - 600 mA Shaft length: 2.4 cm
Components Specifications Motor Driver The L293 and L293D are quadruple high-current half-H drivers. The L293 is designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 36 V.
Components Specifications MCU Atmega16 It is Low-power AVR 8-bit Microcontroller with 16KB In-System Self-Programmable Flash.It has 32 Programmable I/O Lines with Real Time Counter with Separate Oscillator & Four PWM Channels
Components Specifications Voltage regulator (7805) 7805 is a voltage regulator integrated circuit. The voltage regulator IC maintains the output voltage at a constant value. It provides +5V regulated power supply.
Complete Schematics Image from simulation file of Proteus Transmitter Side
Complete Schematics Receiver Side Image from simulation file of Proteus
ALGORITHM Accelerometer It will detect the gesture and send analog output to the ADC of Atmega16 on the corresponding axis. Atmega16 The Microcontroller will send the command based on threshold set on the ADC of respective axis to the RF encoder Module. RF Encoder The Encoder Module (IC HT12E) will send the correscponding Databit using RF transmitter to the RF Reciever. Transmitter Side
RF Decoder The RF Reciever will send the command to IC HT12D and the corresponding Data bit will be pulled high. Atmega 16 By checking the status of Data bits of the Decoder IC the microcontroller will send the command to the motor Driver to start or stop the motors. L293D It will Recieve the commands from the Atmega16 and will Reverse the polarity/diretcion whenever required. ALGORITHM Receiver Side
Limitations & Further Developments Speed Control Hardware Complications Specific gestures
Conclusion Gesture control which is a emerging technology finds many applications in various fields. The work we have done is a little part of it. Controlling the motion of wheeled robot through this system is not the only thing, with further research we can take it too far.