The Automatic Toilet Flusher

This project was started as a fun weekend task to solve a nagging problem with the toilet in our home - the need to hold the flush handle down while the toilet goes through its entire flush cycle. Apparently, this common issue could have been fixed by just replacing some components in the toilet, but I'm an electrical engineer, not a plumber, and I wanted to create a solution on my own terms.

Not one to waste time, I set about building a small electronic flushing system using a BASIC Stamp 1, servomotor, and serial LCD. A high-torque Hitec servo attaches directly to the flushing handle of the toilet. To fix the servo into place, I used double-sided foam tape and zip-ties secured against a large steel L bracket screwed into the wall. It's not the most visually stimulating of solutions, but it does the job.

 The operation is quite simple. First, the BS1 waits for a button press from an external doorbell push-button. Once the press is received, the BS1 moves a servo from an idle position to the flush position for a preset amount of time (in our case, approximately 10 seconds) and then moves the servo back to idle. To give me an idea of how often my wife and I use the toilet, the total number of flushes since last system reset is displayed on a backlight-enabled serial LCD module (#27977). All of the circuitry is mounted inside a plastic project case and double-sided foam taped to the top of the toilet. The entire system is powered by a 12V, 5A DC supply hidden behind the toilet.

So, if I can save 10 seconds per flush on an average 6 flushes a day, that saves me 1 minute a day or just over 6 hours per year. That would give me enough time to work on another project!

Relevant Source Code (.zip)