#23: Preparing your home automation system for death

Building a home automation system is a lot of fun, but there’s a serious issue you need to consider: what will happen when you’re gone? Will anyone else be able to figure out the system that you put together?

A couple of years ago, software developer Chris Yeoh passed away after a battle with cancer. Even with time to plan, his passing still left some systems in his house inaccessible to his wife and young daughter. His situation made me think long and hard about what would happen to my family if the same thing happened to me.

I have a couple of suggestions for ways to prepare your system for dealing with a future without you.

Bootstrapping documentation

If you’re gone, and a random electrician is called in to figure out why the lights aren’t working, will they throw up their hands in disgust and walk away? The first thing they’ll do is open the switchboard to orient themselves, so put some obvious bootstrapping documentation right there at the switchboard.

When I first started taking electronics apart in the 1970s, it was normal for major appliances to have physical documentation inside them. If you take the back cover off an old black and white TV, it may have the complete circuit diagram glued inside for the benefit of service technicians. I’ve even opened up old TVs to find a complete factory service manual packed inside.

I keep a master document in Google Docs, and a hard copy on a clipboard hanging next to the main switchboard. Whenever I make a change to the cabling or anything else relevant, I write the changes in the hard copy. When a few changes have accumulated, I take the clipboard to my computer and edit my master copy. Then I print it out again, put it on the clipboard, and leave it with the switchboard.

My document contains:

• Name and phone numbers of myself and my wife.
• Name and phone number of our electrician.
• WiFi SSID and password.
• Name of my ISP, account ID, password, tech support phone number, and fault history.
• Name of my cable TV provider, account ID, password, and fault history.
• A plan of my house, with important locations (such as all switchboard locations) marked.
• A definition of the labelling scheme for network connections.
• A list of Ethernet ports and their uses.
• A definition of the labelling scheme for power cables.
• A list of relay outputs controlling loads in the house.

You can see a template version in Google Docs, and either duplicate it for your own use or download it as a Word doc or other format:

https://docs.google.com/document/d/1B9N5zjWe61BWN3E9MIRnA-a-sEtzdo1qJcFtI-x61R8/edit?usp=sharing

Storing source code

When you make something for your home automation system it’s usual to test the firmware, modify it until it’s working just right, and then walk away and forget it. The source code for your project is probably sitting in some obscure location on your computer, which nobody else can access. Or if they can access it, how do they know this particular Arduino is running the sketch called “SensorShield4MQTT” instead of the other one called “SensorInputsMQTT”? Or which versions of the libraries you compiled it with?

When I finish a project, I copy the source code and associated libraries onto a cheap USB memory stick or an SD card, and then put it inside the project box or attach it with a cable tie so that it always physically stays with the project.

Later, if I ever update the firmware, I also update the memory stick so that I know 100% for sure that it always contains the exact source code that is currently running on the device.

This has saved me hours of frustration on multiple occasions, and if anyone else ever wants to fix the systems I’ve built this should put a smile on their face.

Other ideas?

I’d love to know if you have other suggestions! Please comment below.

Finally, please consider supporting a cause such as Free To Breath and help fight cancer.