5o $ robo urgent help

[aruna1]

Today I went to many electronic parts dealers to buy a ATmega8 inorder to built 50$ robot but non of them even heard about it.I guess it's because robotics is not a popular subject in my country and very few people are interested in robotics.so my question is

can we use a PIC as a replacement of ATmega8(like pic16F84)? if can which PIC it would be and can you give me a circuit?

how to use a pic to identify voltage difference(not like 0v and 5v i want to compare voltages in two sensors and controll robot with that input)

i hope you guys can help me with this.

and is there any site that i can buy ATmega8 at cheap price which deliver the item to Sri Lanka.


Thanks

[Trumpkin]

can we use a PIC as a replacement of ATmega8(like pic16F84)?

I'm pretty sure you cannot.

how to use a pic to identify voltage difference(not like 0v and 5v i want to compare voltages in two sensors and controll robot with that input)

You don't need a micrcontroller for that, just use a comparator. You can find an example of a comparator here http://www.robotroom.com/Comparator.html

[aruna1]

can we use a PIC as a replacement of ATmega8(like pic16F84)?

I'm pretty sure you cannot.

how to use a pic to identify voltage difference(not like 0v and 5v i want to compare voltages in two sensors and controll robot with that input)

You don't need a micrcontroller for that, just use a comparator. You can find an example of a comparator here http://www.robotroom.com/Comparator.html

well i found following topic where members sugest different PIC's  but none of them have posted a circuit diagram.please read this topic and post a circuit which i can use pir,light,infrared sensors
thnks
http://www.societyofrobots.com/robotforum/index.php?topic=4419.msg34549#msg34549