MakerPro display options
Some electronics exist in the back of a cabinet somewhere that you hopefully never have to see. Just set it and forget it, and if something malfunctions, perhaps it was time to replace it anyway. In other instances, however, you’d like it to be able to communicate with a human, perhaps using a touchscreen-based human interface device (HID) or other display. Let’s look at a few options for your next project, including the obvious (LCD and LEDs), as well as a couple others that you might not have considered.
[An Arduino board set up with a simple LCD display. Photo by Lukaststanley CC BY-SA 3.0 via Wikimedia.]
Although perhaps not the most exciting display technology for MakerPros today, LCD, or liquid crystal displays, provide an inexpensive way to visualize your data and have done so for many years. Some come in the form of black and white character displays, while the more advanced components act more like what you would think of as a “screen” – an LCD TV for instance – displaying drawings, animations, or whatever else is needed.
LCDs don’t emit light on their own, so you either have to rely on ambient light in the area, or you can add an LED backlight to allow it to produce its own glow.
[Millions of LEDs come together to form the “Fremont Street Experience” in Las Vegas, Nevada.]
Almost as simple as an incandescent light bulb, LEDs can act as discreet indicators. You simply apply current to them and they light up. This could perhaps signal that a motor is activated or that a certain area is not safe to enter. Like LCD technology, in a much more complicated form, they can also be put together to act as a display screen.
“LED” stands for “light emitting diode.” When used by themselves, they can be attached to a circuit board to allow the flow of electricity in only one direction. Though “non-light emitting” diodes are available, LED’s visual property can be useful in some situations.
Electronic ink displays
[A Macro image of a Kindle e-Ink display. Photo by Gijs.noorlander CC BY 3.0 via Wikimedia.]
Electronic ink displays operate in such a way that once a charge is applied to change a pixel black or white, the system no longer has to apply it to maintain its color. This is hugely beneficial for scenarios where information needs to be displayed for a relatively long time while using a minimal amount of power.
E-book readers, like the “Kindle” or “Nook” are probably the best known uses for this display technology, but it’s now starting to filter down into items that you can buy and use, like the rePaper 2.0″ development board from Pervasive Displays. This type of display wouldn’t be good for animations or other fast-moving data visualization, but if you needed something to display relatively slow moving trends or data, it could be a great solution.
[A flip-dot display with a few faulty pixels. Photo by ŠJů CC BY-SA 3.0 via Wikimedia.]
Flip-dot (or flip-disk) displays work exactly like they sound, physically flipping dots to draw characters. Like electronic ink, once a change in the display has been made, power doesn’t need to be applied to maintain an image. You can find this type of display in use in mass transit applications and elsewhere, but as large televisions become cheaper and cheaper, some are being phased out. This gives Makers a nice piece of equipment with which to experiment if they can find one used.
If, however, you have a large budget and would rather forgo recycled terminal signage, as seen on Hackaday, a giant array of these devices can make an extremely impressive display. They also make a fun clicking noise when switched on and off, though in that large-scale example it sounds more like a beehive!
[A Nixie tube clock.]
At one time, Nixie tubes, which resemble vacuum tubes, were used to display fast-moving data from electronic instruments, but as other methods have become cheaper, they’ve mostly been phased out. Besides being relatively expensive, they generally require over 100 volts of DC power to cause them to display, which means relatively complicated control circuitry.
Practically speaking, using Nixie tubes is tough to justify, given the cheaper and easier alternatives. On the other hand, if you want to make something with a truly “retro” feel, like the clock pictured above, these tubes can be an exciting option.