Multi-Segment Displays
Regardless of the mundane nature of what an embedded system does nowadays, the human-to-system interaction often surpasses the role it plays. For example, a simple WIFI-based system may do nothing more than switch a light on and off and yet the display and the big button make it seem like the button of all buttons. You tap it repeatedly and it toggles the light.
A multi-segment display combines multiple LEDs into a single neat package. The package may be compact measuring little more than a CM^3 or bigger on the scale approximating a TV screen. An LED TV is an example of many RGB LEDs grouped together to produce a picture.
When deciding on the type of display you need, you will need to consider the type of data how fast it needs to update, and how far away a reader needs to be. Don't overlook the color, as for data display RED is a better choice owing to the wavelength. RED LEDs are also the most efficient in power consumption ve readability.
- A direct drive: LED Display is one where the are predetermined segments that when illuminated in a specific way, display the information you want. These are usually somewhat limited in the data they can display.
- Protocol: These types of LED clusters may have a number of DOTS or they are a collection of standard LEDs grouped together. The data is transmitted to them using a specific protocol and this results in the display. You may have seen these where the text scrolls and displays messaging at Malls, Sports venues, Airports, etc.
The Direct Drive method is one where power is applied to the segments of a display, and depending on which segments are actuated to complete the circuit, the digit represents the data on display. "1" for example is created by illuminating segments B and C.
The most common of these is the 7-Segment display, where a collection of 7 individual LEDs, called segments illuminate.
When using these types, they need to be treated as LED as far as their power consumption is concerned as they can be burned out.
A short list is provided below of these types.
- 7 Segment
- Dot Matrix
Protocol-driven systems have their applications in environments where information must be available to large groups of people. While there is a higher level of complexity to implement, they can be worthwhile.
Since you may not always find what you need at a store, the option is always available to group a number of LEDs together and assemble your own form of display. Through the course of this section, that aspect of displaying information will be reviewed.
The human-to-system experience is what sells the product, and it is important that the system is "interesting" or "compelling" to use even if all it does is toggle a light switch.
