ball follower robot( IR Sensor)

A Ball follower robot is a very good application of embedded system and robotic. A new  embedded student can make this intelligent robot. Starters was not trying to make the ball follower robot because they think that they need to use a camera for following the ball.this robot use some IR pair to sense the ball instead of camera so you do not need to learn digital image processing.

Now break the task in three different module as per the definition of an embedded system.

ball following concept

1. Sensor module:       IR sensor, lm324 etc
2. Decision module:    p89v51rd2(8051 mc)
3. Actuator module:    L293d(motor driver) , motors etc   

IR sensor principle

SENSOR: Well I chose three IR sensor for sensing a ball and bases on that i can make the decision where to move or in oter words we can follow a ball. IR sensor works on the reflection concept when an Infra-red beam is transmit towards an object it should get reflected by that object and that's how we can recognize the ball. 

IR circuit

IR Sensor

Now the circuit  as we can see in the IR circuit that this circuit gives the high voltage output when the less Infra-red rays get reflected back and a low voltage when high reflection of rays occur. For transmitting we have an IR led which work in forward bias condition and at the reception point we use an IR receiver to accept the IR rays and changes the analog voltages according to that.

comparator

From the IR sensor we get the analog data so we have to change that in the digital format like when an object seen than it should return 0v or 4v or in other word's we can say that in high or low voltages because we kno that in digital high voltage = 1 and low voltage= 0. 

comparator data

For the purpose to change the analog voltage into digital we use comparator which compare the analog  voltage to a reference voltage and give a high or low voltage a desired for controller. 

lm324 comparator ic

 The figure shown here is a comparator IC the pin 1,7,8 and 14 are use to give out put to the micro controller. we should connect a reference voltage to the -ve terminal of this IC lm324 and the out put of the IR sensor to its +ve terminal's.

The circuit show below is for your sensor module this is nothing just the summer of what we discuss in sensor subtopic.

IR sensor with comparator circuit

 PROCESSING: The processing is the most important part of the robot. Till now we get the data from the sensor now based on that data we have to make some decision so here the role of micro controller is come up. we use an 8051  micro controller for our circuit to give them a decision capability. Our micro controller is made by nxp the product name is P89V51RD2. The basic circuit to initialize the micro controller is shown below. we just need an reset circuit and oscillator and bias the controller.

8051 micro controller circuit

 we use the port 1 as an input port and port 2 as an output port.

so the sensor will connect with pin 1,2,3 and motor should be connect with pin 21,22,23,24. 

Now let check how actually we making our decision or our robot how to sense where is the ball and where we have to move.

decision making

 we can see in above figure that sensor 1,sensor2, sensor 3 are three sensor's which gives us a digital data(001,110,010 etc). On the basis of this data we make our decision let us look an example of first figure the robot have to move towards right direction because ball is in right direction. We sense it by our sensor as sensor 1 and sensor 2 will not get reflection of ray so they probably gives 0 to micro controller.

ACTUATOR'S: The Actuator's are those devices which actually gives the movement or to do a task like motor's but their are various types of motor's in the market which works on different voltages. So we need motor driver for running them through the controller. To get interface between motor and micro controller. We use the l293d motor driver IC in our circuit.

motor driver circuit

As in above circuit a 2 pin male connector in connected to the pin 8 this will provide the operating voltage for the motor like if we want to run our voltage on 12volt. so we just have to connect a 12volt power source to this 2 pin male connector.

COMPLETE CIRCUIT OF THE BALL FOLLOWER ROBOT: When we connect all of our module in a sequential way then we can get our complete circuit of the ball follower robot first sensor module and then decision module and in last motor driver.

complete circuit of ball follower robot using IR sensor

 VIDEO OF THE BALL FOLLOWER ROBOT USING IR SENSOR: After making this robot i make a video to give the evidence of the robot.

IMAGES OF THE ROBOT:

 

 ***************************than you ********************************

ball follower robot( IR Sensor)

17:44

self balancing robot

CONCEPT: If we are talking about how a robot can balance itself ?  then every person know the answer . confused! now i am explaining how you balance your self and robot balance itself. When someone trying to push you then what actually you are doing is walking in the direction of the force  this is how you balance yourself and robot balance itself. When you move in any direction then you applying a force against  that direction and this force is equal to the force applying on you. If you are not moving in that direction then you will fall towards the plane.

This is all about the action we take but before taking an action we should sensing  that in which direction we are leaning this sensing can be done by our eyes and neurons system. But the robot sense this motion by various sensors for example: IR sensor, Tilt sensors etc. The motors play the role of actuator or movement of the robot.

COMPONENT'S REQUIRED: The component's required for making a self balancing robot are very common and are easy available in the market. 

Mechanism of IR sensor

SENSOR : For making a self balancing robot we can use IR sensors and tilt sensors. I am using the IR sensor's. IR consist of  led pair one is IR Receiver and IR Transmitter. We arrange the IR pair in this manner when the IR transmitter transmits the infrared rays then they are reflected back to the IR receiver. when receiver receives the infrared it will shows the voltage variation at the receiver terminal this output is then goes to the comparator.

The circuit of the IR sensor is show into the figure. we  can see that we use two resistors one with transmitter and another wit the receiver. The values of the resistors we use are 10k and 330 ohm. 

Circuit of IR sensor

Now the transmitter working n the forward basing this is why in the circuit we connect the IR transmitter +ve terminal with the +5volt and a 330 ohm resistor and then the -ve terminal of the IR led is ground now this will emit the IR Rays regularly

Next we connect a 10k ohm  resistor with +5volt and the other end to te -ve terminal of the IR receiver led and this is the output terminal of the circuit. we connect the -ve terminal of the receiver to the +ve voltage because to make this in reverse bias.

LM324 Op-Amp pin discription

OP-AMP: The Op-Amp is use to make a decision based on the input comes from the IR sensor whenever the IR sensor detects the surface then the output signal is low and whenever their is an absence of surface then output signal becomes high. So, we place two IR sensor on both side of the robot. It will detects the surface and generate a two bits data which is further use to operate the two motors. When the robot is leaning in a direction then the sensor of that side will detects the surface and change its value and motors will moving in that direction.

Here the Op-Amp is  work in the comparator mode. The figure shows the characteristic of the Op-Amp in the comparator mode.As shown in the figure below.

The characteristics of the Op-Amp in the configuration of comparator can be describe as.we can say that when the (v2 is the non inverting terminal voltage and v1 is inverting terminal voltage) v2>v1 then the output voltage will tends to +Vcc and whenever the v2<v1 then output voltage will tends to -Vcc. The output is tends to Vcc but not exactly the Vcc. The output will  goes to saturation voltage.The Ic which we are using is LM324 and having the four Op-Amp.This Ic is easy available in the market.

MOTOR DRIVER(L293D): The IC-l293d  is well known driving the motor these motor are basically work on different voltages so to drive these motor by the signals from Op-Amp we use these motor driver IC. Their are many motor driver Ic in the market but we use the L293D because it is easily available in market. The figure of L293D can be shown. Also the pin description is very important to understand the configuration of the IC. here M1 and M2 are use to show the motors  used in the robot.M1-A or M1-B is use to run the motor in forward direction or in the reverse direction.

L293D motor driver

FINAL CIRCUIT: The final circuit can be shown in the figure below.

auto balance robot circuit

VIDEO OF THE ROBOT:This is the video demonstration of the robot that how the auto balance robot is working.

PROJECT PHOTOS: Images of the projects are here.

 

self balancing robot

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