Hacking a hot water system for home automation

This is a video I did almost a year ago but it’s kinda relevant to Practical Arduino so I thought I’d post it here. My house has a Rinnai Infinity tankless hot water service that heats water to a specified temperature as it flows through the pipes rather than pre-heating it and storing it in a tank. The Rinnai system uses keypads in appropriate places such as the bathroom and kitchen so you can dial up the temperature you want and know it’ll come out of the tap at that exact temperature.

I wanted to automate the process more though so I could do things like walk into the bathroom to have a shower and have the home automation system:

  • Turn on the lights
  • Close the windows
  • Close the curtains
  • Turn on the exhaust fan
  • Pre-set the water temperature

all in one go automatically.

So I hacked a Rinnai controller to link it to an Arduino.

Arduino tutorial video from LCA

The video of our “Arduino: Open Software, Open Hardware” tutorial at linux.conf.au 2009 is now online. Because it’s so long it has been broken into two sections. Sorry about the audio quality: because the front-of-house speakers weren’t turned up loud enough we were speaking loudly directly into the microphone to compensate, and the result is that the audio feed to the camera was clipped and distorted. Hopefully it won’t make your ears bleed.

This is part 1:

And part 2:

Practical Arduino: coming soon to a bookstore near you!

Following on from our “Arduino: Open Software, Open Hardware” tutorial at LCA in Hobart, Hugh Blemings and I have now started work on a book about Arduino projects for Apress. The book title may change at publication time but for now we’re calling it “Practical Arduino“. Our objective is to demonstrate practical applications for a wide range of Arduino form factors and accessories, so we’ll be covering serial commsRFIDBluetooth, servo control, ZigbeeX10, ultrasonics, GPSRF data links, OBD, mass storage, DMX, wearables, accelerometers, and pretty much anything else we can think of. The idea is that readers will be able to either build the projects exactly as presented in the book or to learn from them and take snippets of various designs to use as building blocks in their own projects. As we work through the process of writing the book we’ll provide updates right here about our progress.