Updating / Replacing a 1970's Home Automation System

While not strictly Smartthings related, I would like to tap the Home Automation hive mind on how to proceed with an unusual project:

We recently moved into a house, custom built in the early 70’s for an IBM electrical engineer. One of the (many) unique and somewhat cool features of this house is a circa 1972 DIY home automation system. The UI is rotary dial, and the back end is relays and pulsed controlled stepping actuators. While extremely complex, the system is beautifully engineered, and still largely works 40 years later. There are several controllers (period correct smart phones - ie rotary dials with codes for various lights/scenes) and a many of our wall switches are actually 28VDC momentary switches.

Anyway, occasionally a relay gives out, or one of the logic control boards (logic all implemented on plug in cards with low voltage relays) gets hung up which can be a pain to troubleshoot, and parts are becoming scarce. I would like to upgrade the system to a more modern version of HA. This is why I have been playing around with smartthings in the more recent and conventionally wired parts of our house. The issue is that most of the light switches have 22AWG twisted pair, and all the line voltage wiring for our various fixtures terminates at the relay control panel in the attic. I was thinking that at some point I could rip the relay system out (gently of course so I can preserve it under glass in the smart home museum) and replace it with either a commercial lighting control panel, or about 15 Aeon labs micro smart switches/dimmers:

Any thoughts on this? My hesitancy with the Aeon labs modules is that they may not be the most reliable solution.

The other option is a commercial lighting control panel such as this:
While this is likely more expensive, it is a much more durable solution and allows some pretty cool configurations, this would be much harder to integrate with consumer home automation.

Any other suggestions/ideas on how to replace this beast?


Cool panel. That must have taken a while to set up and get fine tuned.

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Things were a little more involved pre-microcontroller.

Well that is a mighty impressive piece of electrical engineering!

Have you considered replacing the guts of the panel with an Arduino MEGA which has lots of digital inputs and outputs on it that would allow you to keep all of your low-voltage wall switches, although the 28VDC would need to be stepped down to 5VDC. You could get some 8-way or 16-way relay panels very inexpensively to replace the old relays assuming dimming is not required.

Arduino MEGA 2560 - http://amzn.com/B006H0DWZW - $~35
Arduino SmartThings ThingShield - ~$35 (for integration into SmartThings)
SainSmart 16-Channel Relay Module http://amzn.com/B0057OC66U - ~$25

So that is about $100 worth of parts to get 16 relays and preserve the low-voltage switches. Much less expensive than about $675 for 15 Aeon labs micro smart switches.

Plus, the best part is you get to write a bunch of code! That’s the real fun! I have created a re-usable library for the ST Community that actually helps to make this process much simpler.

Check it out at

@urman That was my thought exactly

@rando more pictures please :slight_smile:

Rolling my own with an Arduino or similar definitely crossed my mind and would be in the spirit of the house. I have several Arduino embedded in my camper van, so I am no stranger to using them. However, un the end, this really just has to work and a prolonged development/debug time without light in half my house would be less than ideal. I am looking for a more proven plug and play replacement, which will hopefully last another 40 years! The main reason I am considering the Aeon Labs smart switches is that they would be a drop in replacement - the toggle switches would provide direct hardware control and Z-wave would just be icing for playing around. Yet I am still concerned that this may not be a sufficiently robust and future proof solution.

I don’t think zwave is going anywhere soon. The AEON’s durability?, I’ve got over 20 of these, dimmers and switches they just work. You know that expecting any current technology to be main stream 40 years from now is not going to happen. Anything that you build today is going to look pre-historic 40 years from now, just as your current controller does. I also would go the arduino (or like) route, perhaps you can develop a room by room migration plan.

That is good to hear about the Aeon devices, I am leaning more and more towards these, and purchasing a good pile of spares for the future when they are discontinued. I do expect what ever it is that I install to look prehistoric in 40 years, and elderly in 10 years. However, I would like it to still work at least 10 years from now.

The one thing I absolutely require is that what ever solution I go with cannot require a hub or HA controller for basic functionality. Right now HA is a hobby of mine and I don’t mind futzing with it. But in 5 years, who knows? It appears that the Aeons will work just fine using the momentary contacts to control them without any Z-wave/Smart things intervention - am I right?

yea, they work fine by themselves, they also support several input switch modes (momentary, toggle and three way), this affords several options for the physical switch types used to control them.

SmartThings Hub 2.0 will perform some of the things for light control and basic security with out the internet. And the price is not that great that you can not get it for 3 or more years. If you are talking about 5 years and farther, no one can tell; however, you will be able to enjoy your home automation.

Hi @rando, I have a similar vintage HA system in my home, except there is no central relay cabinet, all the relays are at each individual light fixture.

What system/method did you end up going with to modernize your lighting?

Only one circuit has had an issue in my system, and I replaced that one with an Aeon labs in wall controller. It works perfectly through the existing low voltage switch in the wall. The only issue I have is that because it is mounted in the metal controller cabinet in the attic, I was not able to pair it via z-wave with smart things. This is not a big deal, as this light is just the light for our gear closet, and not something I would care to automate anyway.

Honestly, as long as everything has been working, I have put this on the back-burner as I lost a lot of my excitement for smartthings and HA in general when ST was experiencing tremendous reliability issues a year or so ago. Things seem to be much improved now, I just haven’t gotten my motivation back yet.

Great picture I’d love to use it in a presentation I’m giving is that ok?
Mike (CTO@Arm)