Digital Signage and Raspberry Pi

We’re here to guide you through if you’re looking for answers to your queries regarding Digital Signage and Raspberry Pi combination. As you know, you need an engine behind your display to operate Digital Signage. And this is where Raspberry Pi might come into action. Raspberry seems like the perfect hardware option. It is being affordable and energy efficient at the same time. Regardless of that, let’s have a look at it in further detail.
Now when you take a look at the specifications, you can’t help but wonder if Digital Signage and Raspberry Pi would be a good combination or not. Note that the hardware and software support is quite exceptional. Raspberry Pi can play Full HD videos, it now comes with Wifi integration. And there’s a huge community to help you out.

Specifications Raspberry Pi 3.0 B (February 2016)

  • 1200 Mhz 64 Bit ARMv8-A Quadcore CPU
  • 1024 MB RAM
  • BlueTooth 4.1
  • WLAN b/g/n
  • 10/100 MBit Ethernet
  • microSD-Reader
Digital Signage and Raspberry Pi - Image Rpi 3
Raspberry Pi 3
[/row] Nevertheless, in my view, there are some conceptual drawbacks which limit the Digital Signage and Raspberry Pi combination severely, particularly in a network.

First of all, it was designed as a learning computer and not for media player purposes. For example, the network is connected using a USB hub in order to save costs and the overall performance is just satisfactory. However, the most critical disadvantage is the lack of eMMC memory.

Usually a CMS operates the network in a Digital Signage project for repeatedly change the content quite promptly. So, the players are centrally operable and should be able to submit logs for play or error statistics. For a media player, this means lots of writing accesses to its internal storage in addition to reading accesses. A standard Raspberry Pi does not have any internal storage, so it needs to be upgraded.

Pitfalls in storage purchasing

There are two ways to install this memory; with a microSD card or a USB stick. However, one should not use the cheap consumer-storage. A low-price flash memory, which is primarily for reading only. It is optimize for usage in a smartphone or as mobile storage. For such a flash memory, writing accesses for such a large amount of data can be excruciatingly slow.

Apart from this, such types of flash memory are limited. Depending upon the technology of storage, blocks can allow a maximum of 1,000 to 1,000,000 of erasing and write cycles (P/E cycles) approximately. (Source Wikipedia). Expensive models differ from the cheaper ones in the number of these cycles.

In network based Digital Signage project, a lot of daily content changes and log statistics occur. Hence, you can reach this limit quickly in cheaper consumer-storage.

In principle, since eMMC memory blocks have the same technology, they also have the issue of limited erase/write cycles. However, hardware manufacturers are aware of this issue and hence usually incorporate chips of higher quality. However, a user underestimates the risk of low-priced product and takes advantage of the seemingly favorable cheaper variant.

In 2012, I supervised a project in which the same thing happened due to cost reasons. In the media player consumer USB storage was installed. These USB storage were not even the cheapest available. Nevertheless, in less than a year, the devices failed. In all cases, a technician service was called to replace the USB stick with a higher quality model. This exceeded the actual price by multiple times. You don’t want such a thing to happen in your Digital Signage project.

Industrial Memory as Alternative

You can avoid such a mishap by using an industrial memory in case of Digital Signage and Raspberry Pi. SLC components are one of the highest quality components. You can also use a cheaper industrial MLC flash of a higher capacity, which will allow the erase/write cycles to be evenly distributed. But, it comes with a price:

  • For industrial usage, MicroSD cards with SLC memory. For example, on ATP, the cost of 8GB capacity is about 93 EUR (as of January 2018) Source ATP
  • Industrial MicroSD cards having 8GB of cheaper MLC memory, depending upon the order amount the cost caries between 30-40 EUR.Source Panasonic

We would need a higher capacity to use MLC memory, 16 GB being the least recommended. So, at the end of the day you’d be paying approximately the same cost as that of SLC memory.

The cost aspect of thigh quality USB memory is quite comparable. There are two disadvantages also; a stick requires more power than a microSD card. The Raspberry Pi, having a standard power supply of 2.5 amperes only, could get overwhelme with that. Furthermore, a USB stick extrudes out of the device, requiring space which may not be available.

Cost with Industrial Memory

Raspberry Pi 3 Starter Kit with power supply and housing: approximately 60 EUR (Source Amazon)

8 GB SLC MicroSD: 93 EUR (Source DigiKey)

The pure hardware costs of operating Digital Signage with Raspberry Pi securely in a network are approximately 153 EUR! (As of January 2018)

We can get much more powerful and 4K-capable hardware of at least 8GB eMMC memory or higher in less than 100 EUR. I’ll present some devices of this sort in the future and check their suitability with Digital Signage.

For the sake of completeness

Digital Signage with Raspberry Pi - Image Compute Module
Raspberry Pi Compute Module

A Raspberry Pi Compute-Module 3 with a 4GB eMMC memory is currently available for 30 EUR (Source Raspi-Shop – As of January 2018). However, this module doesn’t come with a WLAN chip, and 4GB memory is only suitable for SD videos and short HD playlists.

Furthermore, you need a carrier board if there’s no slot with the I/O interfaces. This again costs you around 100-110 EUR. Only a few NEC monitors have an onboard Computer Module.

This means that the cost reaches to at least 130-140 EUR, which unfortunately makes it unappealing.

Final Thoughts

In my opinion, if content change and playback statistics are no longer require then you can use Digital Signage and Raspberry Pi. For instance, to run an endless loop of tool demonstration in a hardware shop or play an image video for kitchen equipment in furniture shop. Though, for that one could also use a 5 EUR Raspberry Zero, without WLAN.

However, the situation would change if the content is regularly exchange on a weekly or daily basis and the customer requests the playback statistics. So, you need to upgrade Raspberry Pi cost-effectively. In short, it’s not worth it, and one should consider other alternatives.

In some cases, the Compute Module 3 may be of some help. For instance, if NEC monitors already exist then the content doesn’t require much memory, and we can do without integrated WIFI.

If you have any queries regarding Digital Signage or Raspberry Pi, then mail me and ask away. We’ll soon be coming up with more information regarding other technologies, so keep following our website.

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