The Blog of Ian Mercer.

Home Automation

Cover Image for Home Automation

You'll find many articles on home automation under the tag #homeautomation. Here's a quick overview of the decade-long project to figure out what the ideal home automation system should look like.

My home automation system has over 200 sensors. Most are used to detect people moving around the house. There's a magnetic sensor at the top of the drive that detects cars, motion sensors by the front door, contacts on every external and most internal doors, a few PIR motion sensors in ceilings and on walls, and my favorite sensor of all, the Pulsor strain-gauges under the floor that detect people walking about without any visible sign of a sensor in the room. Many of the sensors are connected through an alarm panel into the main home automation PC using a serial connection but increasingly I'm adding new sensors using Arduinos posting to a RESTful API or Moteino's sending back messages wirelessly.

All the sensor data is stored in a large MongoDB database using my 'variables with history' that make it easy to program complex statistical expressions comparing sensor activity now to the average for the same time of day last week, or every week. From this data a wide-variety of rules are triggered using my 'sequential logic blocks' that make it easy to chain logic together for any situation. The system also uses 'hierarchical state machines' that help track state over time.

The house controls heating, lighting, sprinklers, music. It talks over the speakers, it plays music by tags in any collection of rooms, you can chat to it on messenger, hangouts or Slack. It has a web UI, an Android UI and an iPhone UI.

It saves energy, keeps us informed as to what's happening at home or over at our barn and is generally helpful.

You'll find blog posts on my favorite features, a discussion on representing the home as a graph and much more.

So take a look at #homeautomation.

Related Stories

Cover Image for Bluetooth Tracking Project

Bluetooth Tracking Project

My year long Bluetooth project that won the $20,000 HCI and Microsoft competition during lockdown has continued to grow and now reliably tracks how many people are in the house and outside and can locate any device down to room level.

Ian Mercer
Ian Mercer
Cover Image for Digital Twins are never identical

Digital Twins are never identical

Digital Twin are an online representation of a real world object, a copy of its properties in the digital world and a way to send updated and commands to it. In effect I've been making them for years but now they have a trendy name.

Ian Mercer
Ian Mercer
Cover Image for Home Automation Sensors

Home Automation Sensors

An overview of the many sensors I've experimented with for home automation including my favorite under-floor strain gauge, through all the usual PIR, beam and contact sensors to some more esoteric devices like an 8x8 thermal camera.

Ian Mercer
Ian Mercer
Cover Image for 3d Printed ESP32 Brick

3d Printed ESP32 Brick

ESP32 provides a great platform for sensors around the house but by the time you've added a USB power brick, cable and enclosure it's quite messy. I wanted a device that I could just plug in with no exposed wires and no mounting needed so I designed one in OpenSCAD.

Ian Mercer
Ian Mercer
Cover Image for Bluetooth Sensing for Home Automation

Bluetooth Sensing for Home Automation

Bluetooth sensing for home automation is a great proxy for people counting as it can detect and locate each cellphone in the house. iBeacons attached to tools, cars and pets can provide a 'find my anything' feature too.

Ian Mercer
Ian Mercer
Cover Image for Microwave Doppler Sensors (RCWL-0516)

Microwave Doppler Sensors (RCWL-0516)

Microwave doppler sensors can be found in some alarm sensors but there are also available very cheaply as a separate component. They offer exceptional range but suffer from false triggers requiring a probailistic approach to people sensing.

Ian Mercer
Ian Mercer
Cover Image for Optical-beam sensors

Optical-beam sensors

Optical-beam sensors are reliable and can cover a long-distance such as across a garage or aisle-way. When they include multiple-beams they have good false-trigger rejection.

Ian Mercer
Ian Mercer
Cover Image for PIR Sensors for Home Automation

PIR Sensors for Home Automation

PIR sensors are cheap and easy to use but they suffer from slow response times and low repeat rates.

Ian Mercer
Ian Mercer
Cover Image for Strain-gauges

Strain-gauges

Strain-gauges are my top-rated sensor for home automation because they are invisible, reliable and can be tuned to detect people and ignore pets.

Ian Mercer
Ian Mercer
Cover Image for Event blocks

Event blocks

Home automation systems need to respond to events in the real world. Sometimes it's an analog value, sometimes it's binary, rarely is it clean and not susceptible to problems. Let's discuss some of the ways to convert these inputs into actions.

Ian Mercer
Ian Mercer
Cover Image for Logistic function - convert values to probabilities

Logistic function - convert values to probabilities

Another super useful function for handling sensor data and converting to probabilities is the logistic function 1/(1+e^-x). Using this you can easily map values onto a 0.0-1.0 probability range.

Ian Mercer
Ian Mercer
Cover Image for ATAN curve for probabilities

ATAN curve for probabilities

In a home automation system we often want to convert a measurement into a probability. The ATAN curve is one of my favorite curves for this as it's easy to map overything onto a 0.0-1.0 range.

Ian Mercer
Ian Mercer
Cover Image for Home Construction Advice

Home Construction Advice

Several years ago we did a major remodel. I did all of the finish electrical myself and supervised all of the rough-in electrical. I also put in all of the electrical system and water in our barn. I have opinions ...

Ian Mercer
Ian Mercer
Cover Image for Bluetooth

Bluetooth

One of my inventions recently won a $20k global competition for applications that could help in a pandemic. It uses Bluetooth to count people.

Ian Mercer
Ian Mercer
Cover Image for Probabilistic Home Automation

Probabilistic Home Automation

A probabilistic approach to home automation models the probability that each room is occupied and how many people are in that room.

Ian Mercer
Ian Mercer
Cover Image for Multiple hypothesis tracking

Multiple hypothesis tracking

A statistical approach to understanding which rooms are occupied in a smart house

Ian Mercer
Ian Mercer
Cover Image for A state machine for lighting control

A state machine for lighting control

An if-this-then-that style rules machine is insufficient for lighting control. This state machine accomplishes 90% of the correct behavior for a light that is controlled automatically and manually in a home automation system.

Ian Mercer
Ian Mercer
Cover Image for Home Automation States

Home Automation States

Understanding the many different 'states' a house can have is critical to creating great home automation

Ian Mercer
Ian Mercer
Cover Image for Graphing gigabytes of home automation data with tableau

Graphing gigabytes of home automation data with tableau

Some interesting charts from the gigabytes of data my home automation system produces

Ian Mercer
Ian Mercer
Cover Image for iBeacons for Home Automation

iBeacons for Home Automation

My investigations into using iBeacons for home automation

Ian Mercer
Ian Mercer
Cover Image for iBeacon meetup in Seattle - January 2015

iBeacon meetup in Seattle - January 2015

My notes on the iBeacon meetup in Seattle held in January 2015

Ian Mercer
Ian Mercer
Cover Image for Home Automation Systems as a Graph

Home Automation Systems as a Graph

Using nodes and links to represent a home and all the devices in it

Ian Mercer
Ian Mercer
Cover Image for N-Gram Analysis of Sensor Events in Home Automation

N-Gram Analysis of Sensor Events in Home Automation

Using n-gram analysis to spot patterns in sensor activations

Ian Mercer
Ian Mercer
Cover Image for Xamarin Forms Application For Home Automation

Xamarin Forms Application For Home Automation

Building a Xamarin Forms application to control my home automation system

Ian Mercer
Ian Mercer
Cover Image for The Internet of Hubs (and things)

The Internet of Hubs (and things)

Maybe it should be called the Internet of Hubs instead

Ian Mercer
Ian Mercer
Cover Image for Showing home status with just a single RGB LED

Showing home status with just a single RGB LED

Multicolored LEDs can convey a lot of information in a small space

Ian Mercer
Ian Mercer
Cover Image for A wireless sensor network using Moteino boards

A wireless sensor network using Moteino boards

The diminutive Arduino boards include a powerful transmitter/receiver

Ian Mercer
Ian Mercer
Cover Image for The home as a user interface

The home as a user interface

Ian Mercer
Ian Mercer

A RESTful API for sensor data

POSTing data to a home automation system from Arduino devices

Ian Mercer
Ian Mercer
Cover Image for The Internet of Boilers

The Internet of Boilers

An experiment to measure every aspect of an HVAC / boiler system

Ian Mercer
Ian Mercer

VariableWithHistory - making persistence invisible, making history visible

A novel approach to adding history to variables in a programming language

Ian Mercer
Ian Mercer
Cover Image for A Quantified House - My Talk to the Seattle Quantified Self Meetup

A Quantified House - My Talk to the Seattle Quantified Self Meetup

My talk to the Seattle Quantified Self meetup

Ian Mercer
Ian Mercer

Integrating an Android phone into my home automation system

Some new features for my home automation using an Android phone

Ian Mercer
Ian Mercer
Cover Image for The Internet of Dogs

The Internet of Dogs

Connecting our dog into the home automation

Ian Mercer
Ian Mercer
Cover Image for GreenGoose Review

GreenGoose Review

A review of the now defunct GreenGoose sensor system

Ian Mercer
Ian Mercer
Cover Image for Home power meters revisited

Home power meters revisited

Ian Mercer
Ian Mercer
Cover Image for Home Automation Calendar Integration

Home Automation Calendar Integration

Ian Mercer
Ian Mercer

Smart home energy savings - update for 2010

Ian Mercer
Ian Mercer
Cover Image for A smart power strip

A smart power strip

Ian Mercer
Ian Mercer
Cover Image for What does a Smart House do at Halloween?

What does a Smart House do at Halloween?

My favorite home automation features for Halloween

Ian Mercer
Ian Mercer
Cover Image for Home Automation Top Features

Home Automation Top Features

Ian Mercer
Ian Mercer
Cover Image for Weather Forecasting for Home Automation

Weather Forecasting for Home Automation

Ian Mercer
Ian Mercer
Cover Image for How can I tell if my house is smart?

How can I tell if my house is smart?

Ian Mercer
Ian Mercer

Home Automation Block Diagram

Ian Mercer
Ian Mercer

World's Smartest House Demonstration

Ian Mercer
Ian Mercer

Future proof your home with a new conduit system?

Running conduit can be expensive but maybe you don't need one to every room

Ian Mercer
Ian Mercer
Cover Image for New Home Automation Server

New Home Automation Server

Ian Mercer
Ian Mercer
Cover Image for World's Smartest House

World's Smartest House

Over 15 years of experimentation with home automation

Ian Mercer
Ian Mercer
Cover Image for World's Smartest House Videos

World's Smartest House Videos

A collection of videos about my smart home efforts

Ian Mercer
Ian Mercer
Cover Image for Pressure Sensors for Home Automation

Pressure Sensors for Home Automation

Pressure sensors can detect HVAC system operation and could potentially detect clogged filters.

Ian Mercer
Ian Mercer