Speaker
Michael Wedel
(European Spallation Source ERIC)
Description
Over the last years, powerful mobile computing devices with internet access such as
smart phones and tablets have become ubiquitous. In parallel, new software and services
have emerged that provide a multitude of possibilities to exchange one-to-one,
one-to-many and many-to-one information. This combination of hardware and software
forms an enormous infrastructure that is capable of transferring billions of messages
every day - can it be used in the context of experiment control?
One aspect is distribution of sensor data and status information from "slow equipment"
with relatively low update rates to a group of stakeholders in regular intervals.
A service that is well suited for this form one-to-many communication is [Twitter][1].
Users can send messages, so called "Tweets", about which all "followers" of the author
are notified. The length of messages is severely limited, but images can be included
in the form of a short URL. Twitter offers an [API][2] that can be used through a
[Python package][3], so that messages can be created and sent out programatically.
A home made sourdough fermenter serves as a model system to test this approach.
The fermenter consists of a styrofoam box with two 7W heaters that can be switched on
and off via USB-controllable 240 VAC plugs and a DS18B20 temperature sensor. The hardware
is connected to a Raspberry Pi Model B, which is running [NICOS][4], a Python based open source
experiment control system developed at MLZ. Modules to communicate with the hardware have
been added to the system as well as a module that can publish sensor readings over Twitter
in regular, user specifiable intervals. Whenever the fermenter is loaded with a batch
of sourdough, the temperature and heater status is made available to followers of [@Gaehrold][5],
an account which was created for this purpose.
Twitter also has a private messaging feature, where users can communicate in one-to-one
channels. Another module has been added to NICOS that listens to these messages, executes
contained commands and replies with results. The module allows simple access control based
on Twitter user names, so that commands are only accepted from a limited group of people.
[1]: https://twitter.com/
[2]: https://dev.twitter.com/rest/public
[3]: https://github.com/bear/python-twitter
[4]: http://nicos-controls.org/
[5]: https://twitter.com/Gaehrold
Primary author
Michael Wedel
(European Spallation Source ERIC)
