Cheap Digital Signage using Google Slides & Raspberry Pi ($40 per display)

This robust but inexpensive signage solution requires the following components:

• Raspberry Pi Model 3 (or model 2) computer (~$28 to $35) with a 5v power source
• Micro SD card 4GB minimum (~$6)
• Raspberry Pi case (optional) (~$2)
• WiFi or wired Internet connection.
• Google Slides online account, which is similar to Microsoft Powerpoint.
• A website to host a few lines of HTML code.
• Raspberry Digital Signage Software from BinaryEmotions.com ($35 site license).
• Any monitor or flat-screen with an HDMI input.

Google Slides is a presentation editor similar to Microsoft Powerpoint. Google Slides are presented in a linear fashion, where slides appear in order. Google Slides can be used to edit PowerPoint presentations and can be converted to PowerPoint or PDF.

To Get Started with Google Slides, click here. For more detailed instructions, including switching from MS Powerpoint, click here.

• Because the slide presentations are in the cloud and associated with a Google account, users and owners of Google Slides can edit them at any computer, phone, or tablet without having to carry around a flash drive.
• Multiple people can work on slides and presentations at the same time, you can see changes of others as they make them, and every change is automatically saved.
• Google Slides include a revision history, which allows editors to access any version of the presentation in the past and also keeps a log of who made which edits.
• Simply find an image on any internet web page and use your mouse to drag it from the page of images to the current slide you’re editing. Â This drag-and-drop image import makes Google Slides much easier than Powerpoint which requires multiple steps to add an image.
• Tip: The best looking slide images are those having a transparent background. Â To find images with transparent backgrounds, search for images at http://images.google.com then to display only images having transparent backgrounds, select Tools > Color > Transparent. Â For animated images, click the “Type” drop down then select “Animated”. TIP: Create a “Repository” to store seasonal and unused slides

Create a separate Google Slides presentation where you can keep seasonal and other slides that you may move in and out of regular display rotation. Standard commands that you already know from Microsoft programs (ctrl+x and ctrl+v) can be used to individually “cut” slides from your live Google Slides presentation and paste them your “repository” Google Slides presentation file. If you don’t want to use the keyboard shortcuts for cut and paste, you can (1) right-click on any slide thumbnail to display a (2) context menu with these cut and paste options (see the image below).

You need to find your Presentation ID only once. The Presentation ID will not change for as long as you use (and edit) this presentation file.

1. Click the blue [Share] button in the upper right corner of the screen
2. The Presentation ID is the set of random-looking characters after the rightmost slash (/) it the topmost text box. Â You’ll need this Presentation ID in the next step.

Raspberry Digital Signage software allows you to configure a webpage to display on your screens. Â In this step, we’ll modify a simple HTML webpage that will loop through your Google Slides presentation.

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Below is sample HTML to upload to your hosted website. Â Note that near the bottom you’ll, need to make one change; replace {YOUR_PRESENTATION_ID_HERE} with your presentation ID from the previous step.

An advantage to using this method is that you could theoretically have various Google Slides presentation files and you could swap them out in an instant on all your displays by editing the presentation ID in the HTML file.

From any browser on your desktop or mobile device, you can visit the HTML link you’ve created  to confirm that the slideshow is loading and presenting slides at the correct speed.

<!-- content="xx" where...
xx = seconds between content refresh.. 
3600 = 1 hour refresh 
900 = 15 minute refresh 
note, the refresh command will be used if you're displaying the slideshow link on a webpage -->

<meta http-equiv="refresh" content="3600">

<!-- PARAMETERS for <iframe>, below -->
<!-- id= <-- the presentation id of your Google Slide file -->
<!-- &amp;start=true <-- autostart the slideshow -->
<!-- &amp;loop=true <-- automatically loop the slideshow -->
<!-- &amp;delayms=15000 <-- slide delay in milliseconds 15000 = 15 seconds per slide -->

<iframe src="https://docs.google.com/presentation/embed?id={YOUR_PRESENTATION_ID_HERE}&amp;start=true&amp;loop=true&amp;delayms=15000&amp;" width="100%" height="100%" style="position:fixed; top:0px; left:0px; bottom:0px; right:0px; width:100%; height:110%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;">
</iframe>

The Rasperry PI is a small computer that runs the Digital Signage software to show your Google Slides Presentation on your display.

• I recommend the Raspberry Pi Model 3 (wi-fi, faster processor) or Model 2 (no wi-fi, slower processor). Â The Model 3 has a faster processor and built in wi-fi. You can add wi-fi to the model 2 with an Edimax Wi-Fi adapter (range about 30 ft.) or the TP-Link TL-WN722NCÂ (range about 100 ft.). Both models have a standard Cat 5 ethernet port and are each about $30.
• Wired internet connections are the most reliable. Still, the wi-fi option exists if you’re placing the display where you dont have a wired internet connection.
• A phone charger as a power supply keeps your Pi “always on” so you don’t have to wait for the Pi to start up. You can also use a display’s USB port to power the PI, but then you’ll likely want to wait around each time you switch on the display to make sure the signage has loaded correctly. Also, leaving the Pi powered on reduces the chance of corrupting the software when the Raspberry Pi is powered off.
• The Raspberry Pi arrives without a case, but you can buy them on eBay for a few dollars. Be sure to select the correct case for the model you’ve chosen.

Numbered in the image below:

1. micro-USB 5v Power