hi.. am having an old Refrigerator. Itz continuously working , causes heavy current charge i wish to construct a timer circuitry for cut off the above device am using 8051 micro controller .. I wish to use P1.7 as energizing pin.
i wish to give half an hour cut off after every 2 hours of operation.
so.. help me to create the code .. thanks..
Sorry but 851 sounds like an extremely old processor. Or did you possibly mean the 8051?
Anyway - if you see issues with creating a simple delay, why not use something like a 555 to create the delay? A processor is best when you need some intelligent logic. Refridgerators managed their task long before we got microcontrollers. Cars managed to blink their turn indicator lights long before we got microcontrollers.
Or alternatively - consider looking if the thermostat is still working or if it's the electrical circuit that responds to it that has failed. A trivial OP-amp with a thermistor and a bit of hysterese can manage quite well to have the fridge start to temperature-control the compressor again. But you probably save on your electricity bill by buying a new fridge that probably draws half the power of what your current fridge needed even when new.
Create a timer for 1 second. Start counting to 3600 or 7200.
Surely, what you need is a thermostat - not a timer?!
"Surely, what you need is a thermostat - not a timer?!"
But what would the world be without creative redneck work-arounds?
#23 is an alternative solution to the above problem. thechive.com/.../
www.telegraph.co.uk/.../Will-I-save-money-by-turning-off-my-fridge-and-freezer-at-night.html
I'd say the biggest save is to turn off the fridge and freezer permanently. But it will limit the available food or require constant walks to the nearest supermarket (which might result in a super-body as a side effect).
It's definitely no good for a refrigerator work intermittently. The compressor is fragile to the accumulating shocks.
Check seals. A refrigerator would continue to work when seal fails and heat leak in. Check temperature feed-back loops. When such loops fail, a refrigerator would continue to work until everything freezes.
And a better solution is to replace the antique refrigerator with a new, green one.
Errr - but that's exactly how a traditional (electro-mechanical) thermostat works!!
"Errr - but that's exactly how a traditional (electro-mechanical) thermostat works!!"
Exactly - it's just that many new fridges are so quiet that people don't hear when the compressor starts/stops.