my first project

[kenichi]

i wanna build a pet feeder but i need advice..
i am uncertain to what kinda transformer to use as i havent know what type of motor have a strong turning power. any fan will do .
where can i learn how to select the right component for my project?please direct/advice me on what to learn..
i am on my final year diploma in E&E engineering i seem to be able to use some theory to make a circuit for this project but if there's any other way besides using experience to select type of component please advice me ..
i tried surfing circuit design.. but most lecture videos on circuit design are about microprocessor which is unrelated to this practical project.
if there is a course /book/ video that i need to know to design this circuit please let me know.. this project also need to use an ic ...perhaps i can use 555 +capacitor+variable resistor to make delay but ... if you have any other ideas please share with me..

the condition that my lecturer gave me is that no programming is allowed..
and there will be a question session later on about "the reason why i choose this particular component why not something else?" what should i do so that i can design a practical circuit and answer all their question confidently.. if u guys have any suggestion on what i should learn please tell me and i will look it up...

[pebe]

I have no idea what your circuit is supposed to do. You mention a fan and a motor yet all I see is a photo sensor feeding an amplifier and a relay, with neither a fan nor a motor in sight.

Can you be more specific about the help you want? And what has the circuit got to do with it?

[kenichi]

[quote="pebe"]I have no idea what your circuit is supposed to do. You mention a fan and a motor yet all I see is a photo sensor feeding an amplifier and a relay, with neither a fan nor a motor in sight.

Can you be more specific about the help you want? And what has the circuit got to do with it?[/quote]
of course there is no motor yet comes after relay with fan.. still undecided what motor to use... need to check if available in market near me.. and also need to see if it has high torque...still checking market...the fan is cheap ..just use cpu fan..hmmm.. what is your approach to design the circuit.. maybe you would calculate the torque needed then find the motor from there figuring out the type of transformer.. then the IR circuit.
when cat is standing between ir circuit the motor runs for 2 to 3minutes then stop even if the cat is still standing there.. but fan keep on rotating as long as the cat is standing between the ir transmission . i think i would use a large capasitor using it's discharge as means to supply voltage to the motor but large capacitor probably could damage the 555... dilema dilema.. haha..

[pebe]

If you are in your final year diploma in E&E engineering, then you should have learned to express yourself better than that!
You should give a broad outline of what you wish to achieve - then fill in as much detail as you can.

Is the fan to cool the cat, or are you trying to use a fan as a motor to do something else? If so- what? My crystal ball does not tell me!