Principles and Guidelines for Applying Digital Signage Technology to the Needs of a Project
Digital technology is constantly changing and affecting the way companies do business.
It is difficult to keep up with all the possibilities and options. However, there are certain foundational principles that should be generally known and applied as is appropriate to the circumstances of any digital sign project. This document attempts to share some guidelines for applying those principles.
The purpose of this document is not to assign roles to the reader. The Electronics Division will make design decisions based on their expertise with regard to matching appropriate technology to project needs. However, this document gives the reader an idea of the most common parameters that need to be taken into account before suggesting a particular solution.
What is digital signage?
Digital signage may include, but is not limited to, LED displays, LCD monitors, video walls, video processing systems, control systems, computer systems (hardware and software), computer network systems, electrical systems, audio systems (in rare cases), etc.
Ad Art’s process:
Research & development testing is required before vetting new technology, a new vendor, or a new integrated system for a specific project. This is done internally by Ad Art Electronics staff. Specifying a system requires understanding of the customer’s goals and intent, existing conditions, and what current technology works well together to form a system that will meet design requirements. Although calculations are involved, determining the best system is not formulaic. Accurate information must be gathered in order for human intelligence to make a sound decision. For every project, vetted technology is matched with the needs of the project.
How is information gathered? Ad Art sales and support staff is instrumental in gathering required information in order for the Electronics Division to make solid recommendations. Staff will perform a preliminary site survey, an electronics job analysis, and technology selection review before specifying a product and estimating costs.
Basic Design Principles for LED Screens
Brightness and Exposure:
For outdoor digital signs, sunlight is a major factor in design. What direction the sign faces has a direct bearing on how bright it needs to be in order to avoid washout from the sun. In the Northern Hemisphere, signs facing North are usually shaded all day, so brightness is not much of an issue. South facing signs are the worst case scenario because they will be exposed to sunlight all day, all year round (in summertime the sun is high in the horizon, in wintertime the sun is low in the horizon). East and West facing signs are partially exposed to the sun all year round, with varying intensities occurring as the sun rises and sets. Geographically, some areas have bright sunny days most of the year, while other areas are overcast. The environment may affect exposure to the sun as well - i.e. if the sun will be blocked by large buildings in a downtown area. To combat exposure to the sun in cases that warrant it, high brightness or high contrast LEDs may be specified, which will increase cost.
Viewing Audience and Viewing Angles:
How the display is intended to be viewed is another design factor. Will the viewer be standing, walking, or driving in a car? How close will they be permitted to view the sign, at what angles, and for how long? The answers to these questions will help the Electronics Division to specify a product with an appropriate viewing angle.
In display technology parlance, viewing angle is the maximum angle at which the display can be viewed with acceptable visual performance. The image may seem garbled, poorly saturated, of poor contrast, blurry or too faint outside the stated viewing angle range; the exact mode of "failure" depends on the display type in question. The viewing angle is measured from one direction to the opposite, giving a maximum of 180° for a flat, one-sided screen. Some display devices exhibit different behavior in horizontal and vertical axes, requiring users and manufacturers to specify maximum usable viewing angles in both directions. Usually the screens are aligned and used to facilitate greater viewing angle in horizontal level, and smaller angle in the vertical level, should the two of them be different in magnitude.
With LED displays, Ad Art typically specifies either thru-hole (DIP) or surface mount (SMD) LEDs for a given project. Usually, it is the viewing angle requirement that drives the decision. SMD LEDs allow for a greater viewing angle than DIP LEDs, but are less bright when viewed directly because the light energy has to be spread over a wider angle.
Display Resolution:
The display resolution is the number of distinct pixels in each dimension that can be displayed. A “pixel” (a word invented from "picture element") is the basic unit of programmable color on a digital display or in a computer image. The physical size of a pixel depends on the design of the LED screen. “Pixel pitch” refers to the horizontal and vertical distance between each pixel in a grid formation. An LED display's “resolution” is its total number of pixels based on a combination of pixel size and pixel pitch. The more pixels there are, the more detail an image being displayed can have.
Resolution is usually quoted as width × height, with the units in pixels: for example, 1920 × 1080 means the width is 1920 pixels and the height is 1080 pixels.
Viewing Distance and Pixel Blending:
Depending on the pixel pitch of the display, a greater or lesser minimum viewing distance is possible before an image becomes “pixelated.” That is to say, there is a minimum distance whereby the human eye with natural or corrected vision of 20/20 can clearly distinguish individual pixels on a particular display. A general layman’s rule of thumb says that distance is roughly 3.5x the distance in feet as the pixel pitch is in millimeters. For example, if a display was manufactured using a 5mm pixel pitch, you would clearly recognize individual pixels on the display at about 17.5 feet and closer (3.5ft x 5 = 17.5ft).
Minimum Viewing Distance Where Pixels Start to “Blend” Using Common LED Pixel Pitches
Viewing Distance (m) | 3 ~ 5 | 5 ~ 8 | 8 ~ 10 | 10 ~ 12 | 12 ~ 16 | 16 ~ 20 | 20 ~ 25 | > 25 |
Viewing Distance (ft) | 10 ~ 16 | 16 ~ 26 | 26 ~ 33 | 33 ~ 39 | 39 ~ 52 | 39 ~ 66 | 66 ~ 82 | > 82 |
Pixel Pitch | 3mm
4mm |
5mm
6mm |
8mm
10mm |
10mm
12mm |
12mm
16mm |
16mm
20mm |
20mm
25mm |
25mm
30mm |
Of course, the minimum viewing distance is not the maximum viewing distance (or “Retina” viewing distance). The maximum viewing distance is where the human eye with natural or corrected vision of 20/20 can no longer discern individual pixels on a particular display. Standard visual acuity (20/20) in the US or (6/6) in the EU is the ability to discern two points separated by one arc minute. About 300 pixels per inch at 25 cm. This translates to 12 pixels/mm at 250 mm distance.
A general layman’s rule of thumb says that the maximum viewing distance of direct view LED displays is roughly 8x the distance in feet as the pixel pitch is in millimeters. For example, if a display was manufactured using a 5mm pixel pitch, you would begin to lose visual acuity at 40 feet and further. (8ft x 5 = 40ft).
Power Requirements:
Power connectivity is the responsibility of the customer. The Electronics Division needs to know how the sign electronics will connect to power in order to accurately design the system. At a minimum, we need to know what voltage, amperage, phase, and wire count is feeding the electrical panel that will feed the sign(s). If there is not enough existing power to meet the requirements of a particular digital sign proposal, then either the sign design will have to change or more power will need to be brought to the site.
Data Requirements:
Data connectivity is the responsibility of the customer. Typically, it is best practice to require the customer to house control equipment in a climate controlled room and provide a wired data connection (either fiber optic or CAT6) from wherever the control computer will be located to the sign location.
Location of sign controller computer:
It is best to locate control equipment in a building, preferably mounted in a rack in a data-com room. The room must have a 120 VAC outlet for power and an RJ-45 network jack available that will allow the computer to be connected to the Internet. If digital signage is indoor, it is preferred to locate the control computer near the location of the display.
Internet connection:
In order for the sign controller computer to be remotely accessed for content management and maintenance, an Internet connection is required. If the computer is attached to an existing LAN, it is the customer’s responsibility to provide connectivity to their existing network that allows the computer to access the Internet. Wired connections are best practice. If this is not feasible, then wireless Ethernet or cellular technology can be used. We only specify wireless Ethernet communications as a last resort, since that forces the control computer to be housed at the sign location. This may cause durability concerns, security concerns, and reliability concerns when the display is outdoors. Wireless is a less reliable communication method than wired, with more points of failure, and requires more maintenance.
LED data communications:
We require a CAT6 cable to be run from the sign controller computer to the LED Display cabinet (in conduit for outdoor applications). It cannot exceed 330 feet. We highly recommend a secondary CAT 6 cable be provided to serve as a redundant backup. Sometimes, the conduit for data cable can be run in the same trench as electrical cable runs. If the distance exceeds 330 feet, then fiber optic should be used.
Basic Design Principles for LCD Screens
The principles for designing an LCD screen system are basically the same as those for designing an LED system with a few comparison amendments, such as:
- LCD Screens offer lower pixel pitches with higher resolutions, so you typically get higher resolution with an LCD screen that is the same size as an LED screen.
- In general, LCD screens are not as bright as LED screens, so they are typically specified for indoor locations (unless they are outdoor rated and/or shaded).
- The cost per pixel is typically less with LCD screens than LED screens, so LCD technology tends to be more cost effective than LED for large indoor displays that require high resolution (like video walls).
- LCD screens typically consume less power than LED screens of the same size.
- Both LED and LCD screens generally have the same warranty period, but LED screens tend to have a longer service life.
Basic System Design Principles
The electronic display is a main part of the system, but other components are necessary to have a functioning digital sign. In order to display the right content at the right time you need (at minimum):
- A video source (typically a player computer)
- LED control system for LED displays
- Content management system (CMS) software
Ad Art has vetted 3rd party products that exceed the needs of most use cases for the above system components. In addition, Ad Art has developed proprietary computer systems that provide stable, reliable playback of content and allow for secure remote support.
Ad Art Supported Vendors:
Ad Art is able to specify, test, and validate any product from any vendor in order to custom design a control system. However, Ad Art has chosen standard, approved vendors because of the value their products provide. This allows Ad Art to streamline a cost effective solution for most use cases. Some supported vendors are:
- LED Control Devices: NovaStar
- General Content Management Systems (CMS): Onsign.tv, Scala
- Sports Venue Scoring and Content Management: ScoreVision
Defining the Needs of a Project
Below are outline statements and some common questions that come up during various stages of a digital sign project. Although not all questions apply to all jobs, it is good to have them in mind. They serve as a mental prompt to make sure nothing is being overlooked when it comes to designing a system. The answers to some questions are required in order to specify an appropriate solution and accurately estimate the cost of a project.
Basic Project Information:
- Contacts - Job participants vary with each project. Below is a list of potential contacts that may apply. Relevant contact information is needed by the Electronics Division in order to gather appropriate information at appropriate stages of project development.
- Ad Art Staff:
- Salesperson
- Branch level project manager
- Fabrication project manager
- Surveyor
- Customer Staff:
- Owner or administrative decision maker
- Marketing/creative person
- Building/site management person
- IT/networking person
- Customer Third Party Representatives:
- Architect
- Consultants (engineers, design professionals, interior specialists, etc.)
- Construction project management (general contractor, electrician, sub-contractors etc.)
- Ad Art Partners:
- Sign installer/subcontractor
- Project Name - Each “project” is referenced by its sales order number (job number), name, location, and customer.
- Project Location - An appropriate mailing address for the project site is needed to do a preliminary job analysis, site surveys, and further design work. A complete address with street, city, state, and zip code is required so that we can pull up the site on a Google Earth map.
Design Goals and Intent:
It is important for the Electronics Division to understand exactly what the customer wants and needs. There may be technology out there that the Electronics Division is aware of that proves to be a better fit than what is known to sales staff. Some questions that may need answering are:
- How is the sign intended to be used, what is the purpose?
- Why does the customer want this work done and what objectives do their representatives hope to achieve?
- What private, public, and government agencies will need to approve the project?
- Is this a new construction project, a complete replacement project, a retrofit, or any combination thereof?
- Are there customer provided plans/documents available that reflect the design intent?
- What are the customer’s budget constraints?
- When is work expected to begin? When is work expected to be completed?
- Who will be the intended viewing audience of the sign (foot traffic, vehicle traffic, etc.)?
- From what distance, from what angles, and for how long will the signage be viewed by the viewing audience?
- Does the scope of work include indoor displays, outdoor displays, or both?
Content:
Content is a central parameter to matching technology to a project. The choice of content plays a significant role in determining the display resolution, control system capabilities, content management system, network connectivity, and other factors. Some questions that may need answering are:
- What is the intent of the content (third party advertising, self-promotion, informational, entertainment, etc.)?
- What type of content needs to be displayed (still images, animations, pre-rendered video files, live/streaming video, interactive content, live data feeds, etc.)?
- What type of Content Management System (CMS) is needed?
- Does the customer provide their own CMS?
- What are the scheduling requirements for content?
- How secure does the system need to be (private network or Internet)?
- How experienced are customer’s staff at creating content? Will they need training?
- Will the client need Ad Art provided content creation services?
Roles and Requirements:
In order for a digital sign project to succeed, Ad Art, its partners, and end customers all must fulfill their respective roles. These roles must be clearly defined and understood by each party and for each project. Requirements also need to be defined. Ad Art will impose certain requirements on the end customer and the customer may have requirements that Ad Art must meet in order for the project to be successful. In most cases, requirements are negotiable.
Ad Art Provided Requirements:
Power Requirements:
Power connectivity is the responsibility of the customer. Therefore, Ad Art will provide the customer with power requirements of a specified system when new power must be brought to the site. If there is existing power onsite already, power requirements may need to be adjusted based on availability. This could completely alter the system design. In such cases, Ad Art will need to know:
- What is the voltage, amperage, phase, and wire count of the electrical panel that will feed the sign?
- What is the voltage, amperage, phase, and wire count of the transformer feeding the electrical panel?
- How many breakers are in the existing electrical panel, where do they go, and how many poles do they use (single/ double)?
- How many empty spaces are available in the existing electrical panel?
- If the sign will use existing branch circuit conductors, what is the voltage and gauge of the wire?
Data Requirements:
Data line runs and Internet connectivity are the responsibility of the customer. Therefore, Ad Art will provide the customer with data requirements of a typical system. Ad Art typically requires that digital control equipment and computers be housed in a building that is climate controlled with sufficient 120VAC power receptacles. When that is the case, Ad Art typically requires that the customer provide a hard wired data connection from a sign computer or controller to the display screen. The customer is also required to provide the control computer an Ethernet connection to the Internet. In some cases, these requirements cannot be met. For example, a hard line may not be not possible because the customer cannot afford to demolish an existing concrete parking lot to dig a trench, or the control equipment will need to be housed in the same enclosure as the display, or the customer may not have an Internet connection available near the digital sign. Ad Art may provide alternative design options that are not optimal, but still may allow the system to work. In such cases, Ad Art will need to know:
- Why can’t the control computer/equipment be located in a climate controlled building?
- Where else could the control computer/equipment be located? Can it be placed within 330’ linear feet of the digital display?
- If an Ethernet connection cannot be used to connect the sign computer to the Internet, can WiFi antennas be used? Is there an existing LAN and/or WiFi network to connect to?
- If a wireless Internet connection is needed, would the customer prefer cellular technology over WiFi?
- If the digital display is outdoors and over 330 linear feet away from the sign computer, single mode fiber optic cable will be specified by Ad Art for LED data lines. Is the customer able to find/hire a certified fiber optic cable installer?
Customer Provided Requirements:
General Requirements:
Oftentimes a customer will provide a “Request for proposal” document (RFP) that outlines their requirements for an upcoming sign project they wish competing companies to bid on. Even when that is not the case, customers usually impose requirements to simply satisfy the intent and purpose of the digital sign they want constructed. Below are questions that could be asked regarding customer requirements:
- Is there an RFP document available?
- What specific content requirements are there?
- Does the customer require a certain type of content (animations, video, data-driven, etc.)?
- Does the customer need content creation services?
- Do they require remote CMS management over the Internet, or local only?
- What are their content scheduling requirements?
- What training do they require?
- What specific display requirements are there (specific brands or manufacturers, resolution, brightness, color, contrast, size/distance dimensions, etc.)?
- Are there any existing conditions that impose limitations on power or data requirements?
- Are there any laws or regulations that impose specific requirements?
- Does the environment or neighborhood impose any requirements?
- Does the customer’s IT department have any requirements (equipment, security, and privacy)?
Extended Warranty:
Typically, Ad Art provides a standard one year parts and labor warranty for all electronic display system components. Sometimes, the customer requires an extended warranty with specific terms and conditions. In such cases, Ad Art will need to know:
- What are the required terms? How many years parts and how many years of labor?
- What are the required conditions, if any?
Existing Conditions:
Existing conditions have a huge impact in regards to applying the best display technology to a project. The main purpose of a preliminary site survey is to record any and all existing conditions that will affect the choice of display(s). Some questions that may need to be answered are:
- Are there any access limitations to consider (constraints that may limit design parameters or even block access if certain criteria is not met)?
- Is there room for a delivery and staging area?
- Is a lift or crane needed?
- Are there any code or ordinance restrictions?
- If the sign is outdoor, what direction(s) does it face?
- What environmental factors are there to consider?
- Bright sunlight exposure?
- Extreme heat/cold/humidity?
- Weather conditions (heavy rain/snow/ice/sleet)?
- Physical visual obstructions?
- Is there an existing sign structure that will continue to be used?
- What are its dimensions?
- What is it made out of and what condition are the materials in?
- How is it constructed/assembled?
- What parts are reusable and what parts will be replaced?
- Is there existing data infrastructure on site?
- Where is the existing control computer located?
- What LAN/Internet connectivity is available?
- Do new data lines need to be trenched or run?
- Is there an IT department that needs to be consulted with?
- What power is available on site? Is there anything that will limit new power requirements?
Scope of Work:
It is good to define a preliminary scope of work at this stage so as to keep focused on a system design that fits what is proposed. A scope of work summary can be derived from a consideration of the above questions and feedback from the customer.
Matching Appropriate Display Technology
After considering the above questions, and no doubt other factors, the Ad Art Electronics Division will recommend a display system based on their expertise that best fits the needs of the customer. However, their choice is often based on factors that follow general design patterns. The below bullet points outline some of these patterns:
- If the digital sign will be outdoors, it is most likely best practice to specify LED technology (FS series).
- Typically, SMD LEDs are specified for most LED screens because of their superior contrast and their “perceived brightness” is consistent over a wide viewing angle.
- Use the viewing charts available on our website to determine the minimum LED screen size, pixel pitch, and resolution based on the average viewing audience’s viewing distance and viewing angle. Suggest a larger than minimum display if the budget allows for it and it better fits the customer’s design intent.
- For outdoor LED screens, suggest DIP LEDs only if the audience will be directly in front of the screen and there is limited power available, as SMD LEDs consume more power.
- For outdoor LED screens, suggest Ultra-black SMD LEDs if the sign will be facing due south and the budget will allow the extra cost.
- Indoor LED screens are appropriate if the viewing audience will be 20 feet or further away from the screen. Indoor LED screens are brighter and more vivid than LCD and the lower resolution of LED is not perceptible at that distance at most indoor pixel pitches. BIM-Pro series LED panels offer “the best bang for the buck” value and provide the most versatile screen size options.
- LCD video walls typically still offer the lowest price per pixel, so they are an appropriate choice for large indoor screens that require high resolution imagery.
- Avoid situations where the customer is looking for a “flat screen TV” on a low budget. LCD digital signs are in a different league and you get what you pay for. The customer needs to understand the difference.
- Most content management software needs are satisfied with Ad Art provided web based CMS solutions, Onsign.tv and Scala. If the customer requires something different, consult with the Electronics Division staff.
- Most player computer needs are satisfied with our standard Ad Art player. If the customer requires something different, consult with the Electronics Division staff.
- Consult with the Electronics Division staff whenever a specialized LED or LCD application is needed. 3D corner displays, warped or curved screens, mosaic screens, and data driven display systems are just some examples that need special attention not covered by basic design principles mentioned here.