Effective and Easy-to-Maintain Digital Signage on the Cheap

Using Google Slides, a Chromebook, and a Chromecast, it’s easy to create and update digital signage for your organization. This blog post explains how.

My academic department has two TVs in a hallway that we use to display messages. Until recently, we updated the messages by making a PowerPoint, exporting the slides of the PowerPoint as jpeg files, copying the jpeg files to thumb drives, and then plugging the thumb drives into a TV. Surely, there had to be a better way.

Fortunately, there is, and it doesn’t cost too much either. Assuming you already have a computer you can devote to this and access to a web server where you can post web pages, you can implement digital signage for $35, the cost of a Chromecast.

First, I assume you have a Google account. That’s probably a safe assumption. But, if you don’t have one, you won’t be able to use Google Slides, and that is what we’ll be using to create the content we want to display. So, if you don’t have a Google account, sign up for one by going to www.google.com.

Go to https://drive.google.com and log in. Then select New >> Google Slides >> Blank Presentation, and create the presentation you want to display. When you are done editing the content, select File >> Publish to the Web. Accept the defaults and click the Publish button. This will generate a web address that can be used to access the presentation directly through a web browser.

Copy the link into a text file. At this point, it probably looks something like this, except the long, complicated address (the part before “/pub”) will be different:

https://docs.google.com/presentation/d/1rI2fLulkzzhG9u23iyZ6U3hZfnXCttiVBWa8w0kBys8/pub?start=false&loop=false&delayms=3000

Edit this link slightly to this (where I’ve highlighted the changes you should make).

https://docs.google.com/presentation/d/1rI2fLulkzzhG9u23iyZ6U3hZfnXCttiVBWa8w0kBys8/embed?start=true&loop=true&delayms=5000

This address identifies where our presentation can be publicly accessed. It also specifies that, when we access it, we’ll want to embed it within another page, we’ll want it to start automatically, we’ll want it to spend 5 seconds (5000 milliseconds) on each slide before moving to the next one, and we’ll want it to loop when it reaches the end.

Put that text document aside for a moment, and create a new one. Enter this html code into the new text document:

<head>
<meta http-equiv=”Refresh” content=”3600″ />
</head>
<body>
<iframe src=”” frameborder=”0″ width=”100%” height=”100%” allowfullscreen=”true” mozallowfullscreen=”true” webkitallowfullscreen=”true”></iframe>
</body>

This is the code for the web page that we will eventually broadcast to our digital sign. We have one more change to make. Where it currently says src=””, copy and paste the link you edited just a step ago, the one where you had to change the start, loop, and delayms values. For the example of this blog post, the resulting html code would look like this:

<head>
<meta http-equiv=”Refresh” content=”3600″ />
</head>
<body>
<iframe src=”https://docs.google.com/presentation/d/1rI2fLulkzzhG9u23iyZ6U3hZfnXCttiVBWa8w0kBys8/embed?start=true&loop=true&delayms=5000″ frameborder=”0″ width=”100%” height=”100%” allowfullscreen=”true” mozallowfullscreen=”true” webkitallowfullscreen=”true”></iframe>
</body>

This is the html file you will display in a browser on your digital signage. Save it as an html file, and upload it to your web sever. If you then point your browser to that html page, you should see your presentation automatically start, and it will repeat when it reaches the end.

Now, of course, you have to share this to your display somehow. First, you need a Chromecast. Chromecast is a Google-offered device that you plug into the HDMI port of a TV or monitor. The Chromecast wirelessly receives audio/video data from some source, whether it be a computer, DVD player, or game box, and feeds it to the TV or monitor through the HDMI connection. Set up your Chromecast per these instructions.

Then, you need a computer that will broadcast the web page you just uploaded to your Chromecast. I used an old Chromebook, but any computer with the Chrome web browser will work. Open Chrome and enter the address of the web page you uploaded to your web server. Then, from the three-dot menu that appears in the upper-right corner of Chrome, choose Cast. Select the name of your Chromecast from the list of devices. Your browser’s contents will now appear on the TV. Make the browser full-screen on the computer by again going to the three-dot menu and selecting the icon next to Zoom that looks like four corners or a rectangle. Your presentation will now occupy the full height and width of the display monitor.

Whenever you need to change the presentation, go directly to Google Drive and edit it. Once you make your edits, they will be automatically saved to your Google Drive. Because we included the line

<meta http-equiv=”Refresh” content=”3600″ />

at the top of the web page, our display computer will pull the latest copy of the presentation every 3600 seconds. So, your digital signage will always be current to within an hour. If you need your signage to update more frequently than that, change 3600 to a smaller number of seconds.

In our particular setup, we have two display monitors that we need to feed content. I connect one monitor directly through an HDMI cable, and I connect the other through a Chromecast. Supposedly, you can connect multiple Chromecasts to a single computer, and this site provides instructions. I have not attempted this myself, however.

With a Chromecast, a modest computer running the Chrome web browser, and a web server where you can post a web page, you can have an effective and inexpensive digital signage solution.

About Ray Klump

Professor and chair of Mathematics and Computer Science Director, Master of Science in Information Security Lewis University http://online.lewisu.edu/ms-information-security.asp, http://online.lewisu.edu/resource/engineering-technology/articles.asp, http://cs.lewisu.edu. You can find him on Google+.

One thought on “Effective and Easy-to-Maintain Digital Signage on the Cheap

  1. October 9, 2017 at 2:20 am

    Useful Article. Thanks

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