I had a situation where an appliance leaked water while I was out at work. I got home to a mess. A guy down the street had a sewer back up and flood his garage - he was on vacation and didn't know about it for a week. Yuck.

Bob and I decided to solve this problem with a DIY device, and the Internet Connected Water Leak Detector was conceived. It's taken us 11 months to work through the design, make the printed circuit board, test it, and write up complete documentation.

The project is pretty easy to build. You need to be able to solder, but that's it. We have several case designs to fit your own situation. You can 3D print a case, which is dope. Or, if you have access to a laser cutter, you can make a case out of thin plywood (you could even cut this case out by hand). Lastly, we have instructions for using a plastic storage box you can buy at your local office supply store - it's the low cost way to go.

The project is Arduino based and we provide detailed instructions. It's a great project to get started. The heart of the project is a Photon processor from Particle.io. These nifty computers are Arduino compatible, come with WiFi connectivity, and a superb cloud-based network that makes the Internet part of this IoT project a breeze.

Alerts come in two ways. First is the onboard buzzer that sounds; if you're home you'll hear it. Second is using the free Blynk app on your smart phone; when there's a water leak you'll get an alert no matter where you are!

The actual water sensor is connected to the base unit via a 10 foot cable, you could probably make it longer.

Just to make things interesting we included a DHT11 temperature and humidity sensor.

Let me say again, the project has complete documentation. We tell you how to do everything in step-by-step instructions with clear photos of what you have to do. We've made this very easy for you.

Total cost of all parts is probably about $80 and it will take about 5 hours to do it all.

When you're done you'll have a working water leak sensor and an easy IoT platform that you could extend to solve all kinds of problems. Our PCB brings the unused Arduino pins out to a header so you could make this both a sensing device and a controller. Or use some other sensor and make the project into something completely different.

Bob and I do our work as Team Practical Projects and all of the information you need to get going is available on GitHub.

Step 1: The Front Panel

In one step you'll attach two switches and a micro servo to the front panel. The big round switch is the Mute button: if the alarm is going off this button will blink and you can push it to silence the alarm. The servo is used to indicate temperature or humidity. You select which is displayed with the toggle switch.

Step 2: The Case

This photo shows the assembled printed circuit board mounted on what we call the "2D case". This case is a simple one to make. If you have a laser cutter, then it's trivial using the files we supply. You can also make this by hand using a fine saw, a coping saw, and a drill.

Step 3: The Smartphone App

Once your water leak detector is set up, you can monitor it using the free Blynk app on your smart phone. The app will display temperature, humidity, alarm conditions, and has a text box to display messages from the detector.

This is a pretty cool set up. You can easily modify the Arduino code in the water leak detector to send other messages or information as you like.