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HouseMon is a system used to monitor the houses that we own, including both long term and short term rentals. It provides telemetry that allows us to detect future issues with our properties.

High level requirements include:

  • Low capital and operating costs
  • Fun to build

The telemetry and sensing functions include:

  • HVAC run monitoring: current measurement to determine when compressor and air handler are running, detect conditions where they are running too long, too often or out of sync.
  • HVAC temperature monitoring: measure temperature output at one or more vents, compare to ambient temperature and outside temperature, detect when the temperature delta begins to narrow which may indicate refrigerant leak or other problems.
  • HVAC air flow: trend air flow velocity to detect when filters need to be changed
  • Appliance current monitoring to detect usage: especially for EV chargers to determine use patterns and estimate costs. Monitoring hot water heater can detect trending that may indicate problems. Can also detect burned out bulbs by correlating a switch that is on with low current draw.
  • Ambient temperature and humidity: detect trends that may lead to problems due to high humidity in certain rooms or crawl space. Can also warn of freezing temperatures which may lead to problems.
  • Pool water level: detect water level drops that may create operational problems
  • Pool water temperature
  • AC mains availability: report on outages
  • Water flow measure: detect system leaks, faucets left open
  • Water leak detector: detect presence of water to detect leaks


Telemetry Aggregator

The is a set of nodes that receive data from gateway nodes and stores it for rendering in graphics or generating alerts.

House Gateway Node

The gateway node is responsible for:

  • Collecting data from data collection nodes and forwarding to the telemetry aggregator
  • Wifi network for data collection nodes
  • Scheduling sensor readings
  • Managing configuration settings for local devices
  • Provides link to the internet via cellular or routing through on-site network
  • System monitoring and management
  • Some telemetry collection where appropriate - so it may serve as a data collection node as well as a gateway

The Gateway node hosts a wifi network that uses credentials to join - this is the only security for the link between the gateway and data collectors.

Gateway Node Hardware

Data Collection Nodes

Data collection nodes are connected to sensors and generate telemetry that is fed into the system.

Data Collection Node Hardware describes the boards and sensor hardware.

Data Collector Protocol describes the protocol recognized by the data collection nodes

housemon.txt · Last modified: 2022/11/13 12:27 by glen