Raspberry Pi Project 2 – Raspberry Pi driven digital signage and environmental monitoring
I came up with this idea at work (Oxford Brookes University) since, IMHO, our current digital signage platform leaves room for improvement. On the plus side this means we’ve already got huge modern LCD TVs hanging off the walls all over the place with additional power and network sockets next to them.
So I came up with this cunning plan to strip out the existing mini-itx PCs (which aren’t in use at the moment) and replace them with RasPi board which could then also double up as a environmental sensors platform and perform various other duties.
This is my initial project draft, any feedback is very welcome
The Project Draft:
The cost of a RasPi board is currently about £25 but will come down soon as production numbers increase. We have the main distributors (RS/Farnell on our official supplier list).
Under full load the RasPi will consume under 3W which will be less than £1.50 per year (commercial low consumption rate) and less than what the usual 240V->5V USB power adapter consumes (<- this powers the RasPi).
The board will run off batteries for quite some time and a mid sized solar panel+small battery would be enough to run it continuously.
The board can also be run off PoE although this is not officially supported yet.
Additional kit required to run the RasPi (estimated cost, some optional):
- 240V->5V USB adapter £5
- micro USB cable £0.50
- HDMI or HDMI->DVI cable (depending on length) £5-25
- network cable (depending on length) £1-10 [optional]
- kb/mouse (wired, more expensive wireless options will work as well) £10+ [optional]
- USB wifi dongle £10+ [optional]
It will connect to our wired network as well as eduroam (the later requires an additional USB dongle)
It will accept standard wired/wireless keyboard/mouse as well as other forms of input (push buttons etc)
Displaying visual content:
It will play full HD video and run a full linux desktop (Debian are providing the current official image) which means we could have it displaying:
- full HD video through HDMI/DVI (all recent TVs/screens will have this)
- due to above transmit live video feeds like the ones we have at graduation
- streaming TV, e.g. BBC HD via iPlayer works under XBMC
- slide shows/presentations
- run a browser in full screen to display whatever we have sitting on our remote webserver (news feeds, twitter streams, video streams etc)
- remote desktop into each raspi (remote maintenance, ad hoc display of content)
Displaying interactive content:
If we supply the people underneath/in front of the raspi-screen with means of input we can very easily create interactive scenarios:
- red/green button voting with live stat feed above
- feedback entry/registration forms
Harvesting environmental data:
In addition to the above the board will also happily talk to standard sensors through its I/O pins.
- The classic temperature/humidity/light level combo would cost less than £7 per node in very low volumes.
- A long range RFID/NFC reader (less than £80) would extract data from RFID/NFC tags within 10-15m range. Strategically placed at entrance/exit points this could form an attendance system if we add RFID/NFC chips to our student cards. Many users will already carry said tags in their wallet/phone so we can use these (anonymised) in the mean time to get a rough idea of attendance for lectures and events with external visitors.
- placed at store room entrance/exits this would be able to automatically keep an inventory or stored content if content is equipped with RFID tags (pence per tag)
- Addition of a RF or XBee module would allow to span a mini network around a RasPi node with more XBee/RF nodes to gather more accurate readings
- Data from above sensors can simply be stored in a database (MS/Oracle/MySQL) and then processed further for reports (BusinessObjects, QlikView, Flot etc)
- A RasPi 14megaPixel camera is about to be released so these boards could support CCTV/crowd control
Improvements compared to the current platform:
- The above will work without the need for a bought in system. Most basic system would run a full screen browser off a web server.
- A web server based backend will be easy to setup, be maintainable with a wysiwyg editor and provide the feature rich presentation of a modern web site.
- Open digital signage platforms like xibo (http://xibo.org.uk/) should run on RasPi
- It would be possible to quickly react to newly emerging standards and content with a web server based setup
- The current system appears based on mini-itx-ish machines. These will cause a considerable amount of maintenance work due to their small form factor and hence tiny fans.
- A RasPi platform would have no moving parts, be almost maintenance free and clients would have a very long life expectancy as well as low replacement cost.
-> The platform will have a far lower TCO and especially consume considerably less power than the existing one (currently the PC and TV will draw about equal amounts, the RasPi would be negligible in regards to power consumption compared to the screen).
Additional benefit for us as a University:
Another good reason to do this with RasPi would be the fact that it is marketed specifically for educational purposes. Given it’s low price and backing by a strong community it is only a matter of time until we see students with programming skill on and an interest in this platform. Last semesters PG computing students I study with were already plotting RasPi dissertation proposals which might only get delayed due to the lack of available boards.
Having the above system in place would allow us to offer students to help improve the setup which would provide them with valuable practical experience in embedded/SOC development in general and programming for the very popular ARM platform in particular.
I shall talk for a bit about the RasPi at the Brookes OBIS away day.