Power-on Delay with PIC Microcontroller

[emavil]

My area is prone to power interruptions. I saw the potential of pic microcontrollers in helping me saving electric bills by delaying the startup time of Refregirators, etc. Of course there are lots of electronic circuits that can solve this. I would like to use PIC16F84A microcontroller to monitor the mains stability. How can we solve this? And one more thing, it is nice to look at the project with digital voltage display of the main voltage reading for information purposes. anybody who has an idea of reading the actual 220vAC or 110vAC line using pic microcontroller?

 

[IanP]

I don't think PIC16F84 is the right choice for this application ..
And the simple reason is that it doesn't have A/D converter - rather choose one with A/D build-in, for example PIC16F88 ..

You can use a small transformer to step down voltage for two purposes: to supply the PIC and to sense/measure the mains voltage ..
As the mains voltage can be treated as a sine wave conversion from peak voltage (after rectifcation) to RMS voltage shouldn't be difficult ..

Regards,
IanP

 

[emavil]

Thanks for the reply. I really appreciate it. Could you please give some tips on how to manage the dectection of power for processing of microcontroller. May I ask also a sample schematic.

 

[IanP]

Take a look at the picture below .. you can use section of this circuit which uses an optocoupler to generate "voltage present" signal ..
In this example this signal is fed to pin 12 ( of whatever), in your application it can be connected to microcontroller's input pin ..

Regards,
IanP

 

[emavil]

Take a look at the picture below .. you can use section of this circuit which uses an optocoupler to generate "voltage present" signal ..
In this example this signal is fed to pin 12 ( of whatever), in your application it can be connected to microcontroller's input pin ..

Regards,
IanP

Thanks for the mains_supply_failure_alarm