Any genious idea

[emenent]

i want to develope a system using microcontroller
(8051 or 89C51) which can perform the following functions.

1--To turn ON the AC load of 220V(i.e cd player) for seven minutes and then turn it OFF
for next seven minutes.
a--the above process should be repeated 16 times.
b--after 16 cycles the units should remain ON.
c--Microcontroller should be able to drive 8 units(AC load of 220V) at one time.

2--All eight units can be pluged in at same time or some of them can be pluged in
after few cycles i.e Four units were pluged in earlier and three were pluged in
when microcontroller has performed ten cycles and one was pluged in when it was
in last(16th) cycle.
a)If the units are pluged in later microcontroller should be able to recognise them
and should deal with new units separtely.

3--i want to attach the LCD display to show the real time as well as the time when the
microcontroller starts running the units.

4--i want to attach one key pad with it so by pressing each key it should tell which unit
is running and what is the cycle of that unit i.e if i press key 4 on keyboard
the LCD display should tell that unit no.4 is running and the which cycle is going on
on this unit,say cyle 12 of 16.

5--if few units are done (has completed 16 cyles) i would like to unplug them and want to plug in
new units
a)If i put new units microcontroller should start running those units.

i know its very difficult design but not impossible...any great idea?

 

[Nigel Goodwin]

It sounds a fairly simple project, basically just a multi-channel timer, should be easy enough to do.

Obviously you need some kind of switching signal when you plug a unit in, this could be as simple as a plug with a shorting link across it. This simply acts as the 'start button' for the timer on that channel.

Personally I'd probably use multiple PIC's to do the job (but I always use PIC's) - use a small cheap 8 pin PIC on each channel, with a larger PIC doing the display and overall control.

But as long as you've got enough I/O, or don't mind using port expanders, a single micro-controller (of any type) should do it easily.