Heyu/X10 electrical appliances runner and state-machine that can run on OpenWRT wifi routers
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Heyu/X10 state machine and controller written in Coffeescript

A Heyu/X10 state machine that runs on the stand alone command line Mozilla Spidermonkey Javascript interpreter, also known as the Javascript shell. This program runs on embedded systems that come with heyu and works perfectly with CRON.


The X10 protocol can control electrical appliances around the house. In our house X10 is used to (remotely) control lights, heating, a water bed and it reboots the ADSL router. For years the heyu tool did the job, loading the scheduler on a device named a CM11A, the schedule created by a Ruby script. The nice thing about the CM11A scheduler is that it runs independently even when computers fail. The not so nice thing is that the CM11A 'programming language' is archaic and limited. I wanted more control and move both the scheduler and state machine to the 'server'.

Also, in earlier times I was running the heyu software on a laptop, which had to be on to program the CM11A. Recently I moved the CM11A X10 controller to a Netgear WNDR3700 wifi router, which also has heyu support. I described that here. The Linux OpenWRT distribution has a package for a Javascript interpreter, which is Mozilla Spidermonkey. It means I can run the controller in Javascript, and write the code in Coffeescript. Nice.

The great thing about Javascript is that it runs almost anywhere! Javascript is fast (enough) and it has a small memory foot print. I am the first to say that programming Javascript is painful when coming from a Ruby/Python world. Fortunately, Coffeescript generates Javascript and takes much of that pain away.

Quick examples:

  heyu-run --id light1 --switch off
  heyu-run --time 2013-04-12 10:45 --id light1 --switch on
  heyu-run --time 10:46 --id light1 --switch off
  heyu-run --exec
  heyu-run --replay

Advantages of heyu-run

The state-machine and event timer is handled by the heyu-run script independently. heyu-run only uses the heyu software to send signals to the CM11A or equivalent controller. In other words, both the heyu software and the X10 devices are considered dumb switches. When any of these gets reset, software or hardware, simply run replay mode to get to the current state. heyu-run works perfectly with CRON.


The heyu-run program gets invoked by the user, and also regularly by a CRON job. In CRON exec mode it reads the timed command queue, and updates the electrical appliances by writing a shell script, which in turn invokes heyu. The queue and state machine are maintained in JSON files on disk. The state machine is simple - appliances are 'on' or 'off'. Later we may add dimming states. Appliances become known to the state machine when they are used the first time.

Because of the state machine, the correct state will be updated even after a computer fails and comes back online.

Setting up the environment

Coffeescript needs to be installed on a workstation (it is not on OpenWRT just yet). On Debian

  apt-get install coffeescript
  coffee --version
  CoffeeScript version 1.1.2
  js --version

Note: older versions of Debian may require building node.js.

This will install Coffeescript (with node.js). To test/run our code on the workstation you will need oosp-js there too. I had to build it from source so it matches the OpenWRT one. E.g.

  /opt/js-1.6.20070208/bin/js --version
  JavaScript-C 1.6 pre-release 1 2006-04-04 (OSSP js 1.6.20070208)

and test

  ./scripts/helloworld.sh /opt/js-1.6.20070208/bin/js
  Compiling coffeescript...
  Running Mozilla javascript shell...
  hello world

Or install the Spidermonkey Javascript interpreter from Mozilla. You'll need File writing support with

make -f Makefile.ref JS_HAS_FILE_OBJECT=1

If you get a 'ReferenceError: print is not defined' it means you are running a non-Spidermonkey Javascript interpreter (probably the one that comes with node.js).

Compile and run

First compile the Coffeescript version to Javascript

  coffee -c bin/heyu-run.coffee lib/*.coffee

set the js alias and run a test

  alias js-1.6=/opt/js-1.6.20070208/bin/js
  js-1.6 bin/heyu-run.js --test
  Tests passed

To use heyu-run on OpenWRT is similar. Install the 'js' package and check the scripts in ./script.


heyu-run does not actually invoke heyu, but it writes a shell script to STDOUT, which invokes heyu. This is dictated by the fact that the spidermonkey edition of Javascript on OpenWRT does not allow for system calls. But actually this is a good idea: the state machine should be independent of the switching system. So, to switch on light1 and update the state machine the command is

js bin/heyu-run.js --id light1 --switch on | sh

and to switch it off

js bin/heyu-run.js --id light1 --switch off | sh

You can see that in both cases heyu gets invoked. To query the current state

js bin/heyu-run.js --id light1 --state 

to program a timer

js bin/heyu-run.js --time yyyy-mm-dd hh:mm --id light1 --switch on | sh

which adds the timed command to the event queue.

Run the script and execute programmed state changes

js bin/heyu-run.js --exec | sh

Exec can be run from a cron job - say every few minutes. We make sure no two jobs can write to the same file at the same time (through a write lock).

To synchronize all appliances to the state in the local state machine, call replay

js bin/heyu-run.js --replay | sh

To switch off all known appliances and remove the queue, simply remove the database files and run --replay. It is safe to run --replay in a CRON job. I run --replay every few hours.

To catch heyu errors you can send the STDERR output to a file and test the error return code with bash. We can also use 'tee' to send output to a log file. E.g.

set -e
set -o pipefail
js bin/heyu-run.js --exec | tee -a heyu.log | sh 2>> heyu.err
echo $?   # 0 on success, 1 on heyu error

A cron job could be to exec every minute and to replay every hour

* * * * * js heyu-run.js --exec | tee -a heyu.log | sh 2>> heyu.err
0 * * * * js heyu-run.js --replay |sh

or, perhaps, more advanced using a script and killing the relay (which sometimes stops communicating when the CM11A resets)

* * * * * cd ~/opt/heyu-run && ./scripts/run.sh --exec | tee -a heyu.log | sh 2>> heyu.err
0 * * * * killall heyu_relay ; cd ~/opt/heyu-run && ./scripts/run.sh --replay |sh

on openwrt make sure to enable the cron daemon

/etc/init.d/cron enable
/etc/init.d/cron start

Set regular job through CRON (here I reset the ADSL modem at 3AM every

21 3 * * * js heyu-run.js --switch off --id adsl |sh
22 3 * * * js heyu-run.js --switch on --id adsl |sh

Which just touches on the power of running a heyu state machine using CRON!!

Bugs / features

It is possible to add multiple events when the state of an appliance gets changed to the timed events queue, also without using the --time switch. The time granularity is one minute or second, so it can be the user adds two or more conflicting events at the same time. Luck will chose which one is the final state(!). To be on the safe side, remove the ambiguous event from the database file or add a timed event one minute or second later.

Planned for / wished for

  • Introduce nicer JS state machine
  • Send update messages to a service such as jabber
  • Write a schedule for Heyu to upload to the CM11A
  • Maybe mix and match with the Heyu state engine


This software is published under the liberal BSD license. See LICENSE.TXT. Copyright(c) 2013 Pjotr Prins