Thoughts on this architecture

Tom Dunne

I've been asked to come up with a public information system for a college campus, that can actually be a project for 2-3 students. You know the type - when you walk into the foyer of a building, there is a large flat-screen tv with current news/information. There are about 10 buildings in total. It's not going to be in any way mission critical, so I am not too worried about students working on it.

I'm thinking of a flat screen tv, with a raspberry PI attached via HDMI cable. The Pi will then talk via the wireless network to a Linux/Apache/MySQL/PHP machine that will store the info to be displayed.

The programming of the PI would most likely be done using Python, it would retrieve data to be displayed from the MySQL database. It would probably refresh around once or twice a day, cycling through a number of info screens. I'd also have a web component where various departments can enter info to be displayed across campus on the screens.

Any thoughts on the pros/cons of such a setup?

oscarBravo

That's more or less exactly how I would have approached it. In fact, I might have simplified it further by having the Pi running a web browser in kiosk mode and just serving the info pages directly from a central web server.

fergalr

oscarBravo wrote: »

That's more or less exactly how I would have approached it. In fact, I might have simplified it further by having the Pi running a web browser in kiosk mode and just serving the info pages directly from a central web server.

Thats sounds simpler to me as well.
Or even just have the Pi running something that displays presentations, or cycles through a PDF.

That way it only needs network connectivity when you want to push/pull an update. It also keeps the Pi extremely simple, and makes it easy to debug - doesn't even have to render webpages.

Do all the rendering on the server, easy to control, change, etc - assuming you don't want any interactivity on the client.

bambam

JavaFX on Raspberry Pi would be fun.

Deliverance XXV

oscarBravo wrote: »

That's more or less exactly how I would have approached it. In fact, I might have simplified it further by having the Pi running a web browser in kiosk mode and just serving the info pages directly from a central web server.

I built a statistics front end like this for work - very easy to implement.

It was built with WAMP on a network server and just displayed to browsers in full screen mode. The webpage was set to refresh every hour which would then pull in new data. No real need for any AJAX magic as the backend numbers were entered probably once/week.

Then came the mundane necessities such as disabling of screensavers and removing sleep times from displays, hard-drives and processors. Looking back, an android stick or pi might have sufficed but there was a few spare XPs knocking around...

I was worried that the browser might leak memory after a long time in use but surprisingly there had been no issues.

Tom Dunne

oscarBravo wrote: »

In fact, I might have simplified it further by having the Pi running a web browser in kiosk mode and just serving the info pages directly from a central web server.

I hadn't thought of this, good idea.

The only issue is the user-interface. The people who will be entering data to display are not only non-native English speakers, but very technophobic. So entering data via a straight forward web interface, perhaps with the option of a theme and convert straight to a static HTML page might be the way to go.

On the flip side, I was hoping to get three projects out of this - infrastructure (physical bits, LAMP config), database/web interface and Pi software. So the "extra" work of development on the Pi is something I may leave in just to make it interesting.

Graham

I'd have the remote Pi clients cache the data (static web pages) so that they will continue to run even without the central update server. This could be where Python could be deployed in replicating the updates from the central server to the remote Pi clients on a scheduled basis. You could get the students to decide whether the updates should be pulled by the remote clients, pushed from the update server or both.

stevenmu

Tom Dunne wrote: »

The only issue is the user-interface. The people who will be entering data to display are not only non-native English speakers, but very technophobic. So entering data via a straight forward web interface, perhaps with the option of a theme and convert straight to a static HTML page might be the way to go.

You could find a suitable CMS and tweak it to suit your presentation/display needs. That would give you a simple web interface for the content creators to enter their content.

You could also consider something a bit more "commodity" for the clients. "Nettops" are very cheap these days, not a lot more than a Pi, and can run Windows or Linux, and would be a bit more standardised if they need to be supported by someone else. That would obviously ruin the fun/novelty of use the Pi though

Tom Dunne

stevenmu wrote: »

That would obviously ruin the fun/novelty of use the Pi though

Um, if I'm completely honest, this is one of the reasons I chose this architecture (currently have one attached to my TV, running xbmc, belting out Radio Nova, controlled by my Android tablet )

jester77

I have something similar setup at work around the different teams. Raspberry pi hooked up to a monitor displaying a dashboard in the browser. Dashboard is generated on a mac mini using the dashing framework. Very light ruby framework running on sinatra and very easy to customise. The dashboard is made up of widgets and they are easy to build with ruby, coffescript and css and you can easily feed in data from anything that has an API.

Tom Dunne

Just a quick update on this.

The students delivered. As suggested above, they went with a browser in kiosk mode, despite my suggestions of using Python and developing their own solution.

They developed a pretty slick web based control panel, with associated access controls and permissions. Management here were easily fooled suitably impressed with the slick visuals and fades between screens of the control panel. I must find out what web framework they used.

When we get back in September we are going to run a pilot across three locations on campus before full implementation. I already have version 2.0 in mind, incorporating video and no doubt a few other features.

It's actually an excellent opportunity the group of students (4 of them) to learn that getting the software developed is only one part of the process. Dealing with the various stakeholders, support, training, physical installation, and even a campus policy for the system is proving a rich and varied experience for them.

It's also fantastic to see the fruits of their labour being implemented in a real-world situation.

Graham

It's great to hear about the results. Did they go with the Raspberry Pi for the clients in the end?

Tom Dunne

Graham wrote: »

It's great to hear about the results. Did they go with the Raspberry Pi for the clients in the end?

They did, yes. In fact, over the past 6 months, I've ordered about 25 of the things, for projects and for classes.

I'm turning into a Raspberry Pi evangelist. :pac:

PrzemoF

Thanks for the update! I hope it's an open source project!

The Corinthian

oscarBravo wrote: »

In fact, I might have simplified it further by having the Pi running a web browser in kiosk mode and just serving the info pages directly from a central web server.

That's basically how the displays on buses/trains in Germany and Switzerland work. They take in a JSON feed and render it using Javascript/CSS. They don't use Raspberry Pi though.