Digital Signage Screensaver

This device was built for a potential client when I worked at Exitech Digital.

The client needed a PC monitor on the counter which they could use to quickly share their screen with the customer, but the rest of the time show advertising content.

The easiest way to integrate this into an existing system would be a box with an HDMI input from a PC, an output to a monitor, and a button which would switch the PC onto the monitor for a set period, say 60 seconds, and then time-out and go back to advertisements.

I therefore was tasked with quickly building this device in time to demonstrate to the client at our next meeting.

You can see in this picture an early "test fit" when I was deciding how to make all the components sit snugly in the chosen case.

To keep development time to an absolute minimum, amongst other reasons, we used almost entirely off-the-shelf components. We needed a digital signage media player, an HDMI switch, a microcontroller, and a few other miscellaneous cables and connectors.

The HDMI switch was intended to be controlled by pressing a button repeatedly to switch between 3 inputs. I therefore used a microcontroller to control it for automated switching. This involved hooking it up to two of the switch's channel LEDs, as well as the button, so that it could tell what input was selected and simulate button presses until the desired channel was selected.

One slight snag with this was that the LEDs were PWM controlled! I had to program the microcontroller to measure the pulse length, rather than simply if the pin was high or low. But hey, it worked.

With everything installed there was actually a fair amount of spare space inside. This was eaten up by HDMI cables though.

The last thing to do was to tidy up the rear sockets and add a bunch of labels. You can see here the power socket, HDMI input and output, and a network socket for the media player.

Sadly, whilst the client was very impressed with the unit, they chose to go another route. This demo unit ended up banished to a dark corner of the warehouse, where I believe it remains unused to this day.

- Nathan Dane, February 2024