I always had a bad habit of forgetting to turn OFF equipments after its use. Once, I had a bad experience of leaving the water pump ON for the entire day. I was out somewhere and when I returned back I found out that the overhead water tank has over flown and has drenched the street!

I then decided to make something that will make the devices switch off automatically. I came up with a timer circuit design which was made entirely with logic gate ICs. That was the first version of this project. It worked fine. However, I could not take pictures of that design as it was long gone before creation of this website. 

The second version uses a PIC16F84A microcontroller. This is the first microcontroller that I used and I greatly loved it. The controller is perfect for the job. The timer circuit can make delays from 1 minute to 99 hours and it works flawlessly with accuracy in terms of milliseconds. Here are the pictures of my timer circuit that I have installed for my water pump.

The enclosure is very crude made out of wood. The user interface is very simple, although it has no markings. In fact, my grand mother is able to use it without any problem. The Right side GREEN button is for turning ON the timer unit. The right side RED button is for emergency shutdown. The other two buttons on the left are for increasing/decreasing the timer delay. The 7 segment display shows the time that was set. The switch in the center is used to select the unit of the time delay - either in 1 minutes, 15 minutes, 30 minutes or hours.

This system is been in my home for the past 7 years and its working without any issues till now. This is one of the best project that I have done with some practical use. I am glad that I did it. 

I did not have the schematics for the design as it was designed using expressPCB software. I just drew the circuit layout  as it came to my mind. If I find time, I will redraw the circuit and will update it here. The circuit also has a method to sense the water levels in the overhead tank and operate accordingly, but that was not implemented in the pictures shown above.