It all started one day when I was half asleep. I was getting my first cup of coffee and having to refill the water reservoir on my Keurig. I was thinking what a pain it is to constantly refill this thing. Everything else is automatic so why don't I automate the process.

I used an electric solenoid valve and a constant flow valve in series and a controller with a PIC12F100. You press a button on a membrane switch to start refilling and then you leave. It automatically shuts off based on time.

Originally, I was thinking about sensing the water level and shutting it off when the reservoir was full, but after testing it for three months, I realized that the constant flow valve works really well even though the incoming water pressure fluctuates.