okay thats at least a start thank you very much !!
let me try and be a bit more specific,
this is quoted from my study guide:
you are required to design a temperature control unit that has to perform the following:
-the temp is to be controlled as a function of light intensity, this means the darker it gets the more heat must be generated.
-in order to conserve energy, the part of the system that heats up must have the highest possible efficiency.
-a user interface must inform the user of all operational statuses (eg indicator for heting element on/off)
Design constraints:
- to meet the requirement of high efficiency heating, the heating element must be supplied with dc chopping for this a 555 timer is needed
- the heating element is a 12VDC lamp (type of car lamp) which provides good infra red radiation as a heat source
-power supply of 12VDC
design and contruction:
-heating element to be controlled (60W)
-max temp at 3cm away must be 40 degrees celcius
-controlled voltage
-light sensor LDR or a phototransitor.
and that is about the best contraints that we have, everything else is to your descretion,
so any other components can be used, but also within reason