Electronic – relay or switch that remember previous power status after power failure

integrated-circuitmemoryrelay

I have application which need a push button on/off switch feature. But i need to do something buy which it can remember or store in memory the previous status after power failure. same like home air conditioner which save previous status if power cut and return. One of my suggest do it with IC 555 but i don't think it can remember the previous status if power cut… please give me a cheap solution.. my application consume only 12V and 2A.

Edited:
Purpose of this solution is to power on/off remote application which dose not have a UPS or power backup. I am using Arduino with Ethernet module to remotely on/off system power but the problem during long power outage.. application shutdown and i am needed to power on it again.. I looking for a Solution to store state of application even if power reset.

Best Answer

Offhand, I'd say that an EEPROM is the obvious solution for this kind of thing. They store state even in the face of a total power failure. They're fairly inexpensive, as little as $0.29 each in small quantities (ex: https://www.jameco.com/z/24C01-Major-Brands-2-Wire-Serial-EEPROM-1K-128-x-8-DIP-8_276592.html). The biggest downside is that it means adding extra circuitry to the system, to read/write the EEPROM. I'm pretty sure you could get by without adding a full fledged micro-controller, but it would definitely require at least a few extra components.

Using an SD card could also be an option, but I think this would be even more complicated and more expensive, which might make it less than ideal.