This is an instructible on how to crudely detect water flow in a pipe and drive an ambient display. I am using a piezo transducer, some LED's and an arduino. The device is a rough prototype of what will eventually become a persuasive technology that motivates sustainable behavior and raises awareness about water use.
This is a project by Stacey Kuznetsov and Eric Paulos at the Living Environments Lab, at Carnegie Mellon University Human Computer Interaction Institute.
Living Environments Lab
The video below illustrates a previous version of this project, where a microphone is used instead of a piezo element to detect water flow. You will achieve better performance when using a piezo transducer, so this instructible details the piezo approach.
Special thanks to Briam Lim, Bryan Pendleton, Chris Harrison and Stuart Anderson for help with ideas and design of this project!
Step 1: Gather Materials
- Microcontroller (I used an Arduino)
- Piezo Transducer (http://www.radioshack.com/product/index.jsp?productId=2062402)
- A few LED's (I used 2 yellow, 2 red, 2 green)
- Candle holder or similar-sized container
- 1 Mohm (or other large value) resistor
- 4.7K Resistors (3)
- 1K Resistors (1)
- Low-value Resistors (for the LED's)
- Clipping Wires
- Jumper Wires
- op amp (LM613)
Step 2: Build the Circuit
There is a high-value resistor between the two inputs form the piezo, which acts as a pull-down resistor for the signal.