Semantic Vocab for the Internet of Things
Python Yacc Logos HTML R E Other
Latest commit 18f76a7 Nov 3, 2016 @dpjanes fix package 'homepage'
Failed to load latest commit information.
src add dimmers Sep 27, 2016
package.json fix package 'homepage' Nov 3, 2016



This is the vocabulary for describing Things - Sensors and Actuators - in the Internet of Things.

If you make changes, push them back to us.

We've moved from using iot: names to names from Thing. Specifically

  • additionalType
  • alternateName
  • name
  • description
  • image
  • sameAs
  • url



The source files are in "src". The hierarchical structure of the folders is:

  • iot-unit|iot-facet|iot-placement|iot
  • @type
  • @id (in particular, the part after #) - a file

The files are a simple text format, a key followed by a space followed by a value. Keys may repeat multiple times


description when to end / finish something
format iot:date
format iot:time
format iot:datetime

the schema:name, @type and @id are automatically made by the DoCompose function.


The "published" JSON-LD files are folder pub. Note that the official URL home for these is, not the GitHub folder.

To generate the JSON-LD files from the source files, run:

npm run publish

The program bin/ converts the files in src to JSON-LD in this directory.

Making changes

  • Fork this project
  • Add whatever to src/iot-[something]/[@type]/name
  • Commit
  • Push

If accepted, they will be officially published at

Units of Measure

The Units of Measure are in iot-unit.jsonld from the directory src/iot-unit/Unit

Each unit of measure filename must have three parts, separated by '.':

  • the property
  • the system
  • the name

The property is very loosey-goosey and is meant for humans to read and understand and is based on colloquial understandings of a word rather than a formal defintion. For example, speed and acceleration are grouped together under "speed"; candela, lux and lumen are grouped together under "light".

The property must be one of the following:

  • area
  • energy
  • length
  • light
  • mass
  • math
  • pressure
  • radioactivity
  • speed
  • temperature
  • time
  • volume

The system must be one of the following

  • angle
  • constant
  • fraction
  • imperial
  • si
  • traditional
  • troy
  • us

The name is exactly what you'd expect.

Adding New Units of Measure


  • following the three part convention
  • do not add new things unless you're planning to use it
  • try not add SI multiplier units (e.g. centigram) unless they're very commonly used. Exponents can be added to values if this is needed.