Robots are playing an important role in automation across all
the sectors like construction, military, medical, manufacturing, etc. After
making some basic robots like line follower robot, computer controlled
robot, etc, we have developed this accelerometer based gesture controlled robot by using arduino uno. In this
project we have used hand motion to drive the robot. For this purpose we have
used accelerometer which works on acceleration.
Required
Components
1. 8051 Microcontroller
2. DC Motors
3. Accelerometer
4. HT12D
5. HT12E
6. RF Pair
7. Motor Driver L293D
8. 9 Volt Battery
9. Battery Connector
10. USB cable
11. Robot Chasis
A gesture controlled robot is controlled by using hand in place
of any other method like buttons or joystick. Here one only needs to move hand
to control the robot. A transmitting device is used in your hand which contains
RF Transmitter and accelero-meter. This will transmit command to robot so that
it can do the required task like moving forward, reverse, turning left, turning
right and stop. All these tasks will be performed by using hand gesture.
Here the most important
component is accelerometer. Accelerometer is a 3 axis acceleration measurement
device with +-3g range. This device is made by using polysilicon surface sensor
and signal conditioning circuit to measure acceleration. The output of this
device is Analog in nature and proportional to the acceleration. This device measures
the static acceleration of gravity when we tilt it. And gives an result in form
of motion or vibration.
According to the datasheet of adxl335 polysilicon surface-micromachined
structure placed on top of silicon wafer. Polysilicon springs suspend the
structure over the surface of the wafer and provide a resistance against
acceleration forces. Deflection of the structure is measured using a
differential capacitor which incorporate independent fixed plates and plates
attached to the moving mass. The fixed plates are driven by 180° out-of-phase
square waves. Acceleration deflects the moving mass and unbalances the
differential capacitor resulting in a sensor output whose amplitude is
proportional to acceleration. Phase-sensitive demodulation techniques are then
used to determine the magnitude and direction of the acceleration.
Pin Description of accelerometer
1. Vcc
5 volt supply should connect at this pin.
2. X-OUT This pin
gives an Analog output in x direction
3. Y-OUT This pin
give an Analog Output in y direction
4. Z-OUT This
pin gives an Analog Output in z direction
5. GND
Ground
6. ST
This pin used for set sensitivity of sensor
Circuit Diagram and Explanation
Gesture Controlled Robot is divided into two sections:
1. Transmitter part
2. Receiver part
In transmitter part an accelerometer and a RF transmitter
unit is used. As we have already discussed that accelerometer gives an analog
output so here we need to convert this analog data in to digital. For this
purpose we have used 4 channel comparator circuit in place of any ADC. By
setting reference voltage we gets a digital signal and then apply this
signal to HT12E encoder to encode data or converting it into serial form and
then send this data by using RF transmitter into the environment.
At the receiver end we have used RF receiver to receive
data and then applied to HT12D decoder. This decoder IC converts received
serial data to parallel and then read by using 8051. According to
received data we drive robot by using two DC motor in forward, reverse,
left, right and stop direction.
Working
Gesture controlled robot moves according to hand movement
as we place transmitter in our hand. When we tilt hand in front side,
robot start to moving forward and continues moving forward until next command
is given.
When we tilt hand in backward side, robot change
its state and start moving in backwards direction until other command is
given.
When we tilt it in left side Robot get turn left till next
command.
When we tilt hand in right side robot turned to right.
And for stopping robot we keeps hand in stable.
Circuit Diagram for Receiver Section
Circuit for this hand gesture controlled robot
is quite simple. As shown in above schematic diagrams, a RF pair is used
for communication and connected with microcontroller . Motor driver is connected to microcontroller to run the robot. Motor driver’s input pin 2, 7, 10 and 15 is connected
to microcontroller digital pin number 6, 5, 4 and 3 respectively. Here we have used two
DC motors to drive robot in which one motor is connected at output pin of
motor driver 3 and 6 and another motor is connected at 11 and 14. A 9 volt Battery
is also used to power the motor driver for driving motors.
