Hacking a hot water system for home automation

[SoundsFantastic]

@FlamingoTel Think of the buttons as logic only, they dont actually turn anything on or off. They just send an input signal saying it has been pushed. The arduino will decide what to do when a said button is pressed. Basically your replacing what the keypad did with the arduino which can be controlled by a computer.

[experimental0000]

tankless water heaters ftw!

[alphaman1101]

hmm. that opens my mind some what.

[adfhau]

This raises the same kind of issues to dealing with universal remote controls - knowing the existing state of a device.

As with higher end TV sets that have serial data links for firmware upgrades and computer control, I wonder have the manufacturers of things such as hot water systems considered adding automation friendly features themselves as standard?

I guess the downside of them adding such features is that every company wants to set the standard they use themselves :)

[SuperHouseTV]

Exactly right. Rinnai do actually provide a home-automation interface but I don't know the details of it. I think it has an RS-232 interface, costs many hundreds of $, and requires their proprietary Windows-only software to talk to it. I'm not interested in running Windows so I thought I'd try to hack something up myself.

You're spot on that feedback of current device status is a big issue though.

[PYROYORKDRAGON]

how dose the Arduino know what Tem the panel is on .......i did notice when you pressed the button it beeped you could connect that beep back to the Arduino .... ma by a thought

[SoundsFantastic]

@PYROYORKDRAGON The arduino has INPUT and OUTPUT capabilities, so the arduino can read a temp from a sensor or other device.

[SuperHouseTV]

The microcontroller I use in the video is called an "Arduino". I can't post links in comments so I've just updated the video info with URLs to some relevant sites, including for a book I'm currently writing called Practical Arduino.

[cantbeliveitshuman]

yeah lets all Go void the warrenty! sorry but i was laughing there Lol

[SuperHouseTV]

Or having an extra panel that is never touched (there can be up to 4) and power-cycling it, or zeroing-out the setting by pulsing "down" say 50 times so it hits the end then count back up, or by reading the values on the LED display (which I've tried doing but they're multiplexed, which is a pain to deal with - but a friend suggested using a simple voltage ladder into an ADC so I may give that a go)