Thanks a lot Sir……..

That was just the basic demo to show you how you can read the encoder data into a variable.

“but how will I get the readings in the PC?”

So you want the encoder data on PC, so please let me know the following.

>>Interface between PC and your Robot (Most probably UART).
>>If USART the USART number (ATmega2560 has 4 USART viz USART0,USART1,USART2,USART3)
>>Since PCs now a days don’t have a RS232 (COM Port), so their must be a convertor between your PC and the Robot, what is the type of it ? Is it built into the board?
>> Have you installed the drivers for the above?
>> What reading do you want on PC (the raw encoder data as shown on LCD, The distance in CM or velocity in CM/sec)
>> You somewhere told that you wanted to plot some graph, so please describe the graph what will be in x and y axises.

Download the Basic Encoder Data Reading Demo from here

http://extremeelectronics.co.in/temp/PositionEncoderTest2.zip

This demo shows you how to get the raw encoder data to a variable.

the two variables are

enc_left_value
enc_right_value

for left and right encoders.

This demo simply shows the contents of these variables on the LCD

L: 00028 R: 00092

L stands for Left and R for right.

It is an AVR Studio 5 Project.

The hex file is in the location

\PositionEncoderTest\Debug\PositionEncoderTest.hex
Burn the hex file and see if works.

After burning the program. Rotates the wheels by your hands.
The LCD should update the counters.

Tell me the results. So that we can proceed.

Just configured my LCD library according to your platform.

Please check if it works on your board.

I have already tested on simulation software.

Just confirm me. So that I can move on to write the code for position encoder test.

Attached is the AVR Studio 5 Project.

http://extremeelectronics.co.in/temp/PositionEncoderTest.zip

The hex file is in the location

\PositionEncoderTest\Debug\PositionEncoderTest.hex

Burn the hex file and see if LCD works.

external interrupt lines (INT4 & INT5). So your first task is to initiallize the INT4 and INT5.

Now in the Interrupt service routine (ISR) you need to increment a varriable. After that you

need some basic mathematics. You need to find out total number of slots in the encoder wheel.

And using the radius of the main driving wheel you need to find out how much (in centimeters)

your robot moves for each slot. So you can calculate the displacemnet easily.

Tell me the following if you want me to write some working code for you.
>> Number of slots in your encoder wheel.
>> Circuit diagram of wiring of MOC7811 (does it gives high or low logic for slot)
>> Are you using a ready made board for ATmega2560?
>> If yes the make and model.
>> Does it have a LCD module (will make our life easier)
>> If yes the connection.
>> The frequency at which your ATmega2560 is running (see the marking on crytal)
>> How you are programming the ATmega2560 (which hardware/software you are using)
>> Is your robot ready made or you have made all these (I mean encoder etc)
>> Give me the photo of the encoder arrangement.
>> If ready made name the make and model.

First of all thanks for your compliments!

Sorry to tell but you’re confused!

Please specify the type of encoders you are having may be the part number.

White line sensors are usually simple IR pairs that uses reflectance to sense. Since these are raw IR led + Receiver pair. Their output need to be calibrated for the current application (due to change in parameters like the reflectance of the white surface in use, distance from the sensor, ambient IR intensity etc). These are usually connected to the ADC (Analog to Digital convertor port) of MCU. Reading the ADC channels will just give you the amount of IR radiation falling on them. You can then either make a auto calibrate function that scans the surface and finds the values sent by sensor for black and them white areas.

To send 32 bit int using USART, use following snippet.

uint32_t value=11998652; //32 bit unsigned int value

USARTWriteChar(value);
USARTWriteChar(value>>8);
USARTWriteChar(value>>16);
USARTWriteChar(value>>24);

on receiving side. Write

uint32_t USARTReadUINT32();
{
uint8_t b1,b2,b3,b4;

b1=USARTReadChar();
b2=USARTReadChar();
b3=USARTReadChar();
b4=USARTReadChar();

return ((b4< <24)|(b3<<16)|(b2<<8)|(b1));
}

for furthur discussion please use the forum.
http://forum.extremeelectronics.co.in/