Passive display "pixels?" - Page 1
Forum section: electronics / projects

author: djacobow
author_rank: Super Contributor
timestamp: August 24, 2014, 09:47:05 pm
content: I've had some fun designing a few desk toys that use a matrix of LEDs to "ambiently" show the status of some variable of interest fetched from the internet. For example, I've got one on my desk now that gives a real-time visual indication of the current amount of CO2 being put out by all the electric generation in California.Matrices of LEDs are getting boring, though, and I would like to design something that uses a different display technology, preferably something that is passive; that is, you write to it and the display stays put until you write to it again. Would also be cool if it were not something run of the mill.I'm rather fond of the magnetic flip signs that they use on freeways and such. That is, the ones with little metal shutters that are painted yellow on one side and black on the other, and they are 'flipped' one way or the other to turn a pixel on or off.Does anybody know where you can get a matrix of those? I don't even know what they're really properly called.I'm open to other ideas, too.I like to work with a 16x16 matrix at a minimum so if it's something I make myself, it needs to be simple enough that I can do 1024 of them!

author: miguelvp
author_rank: Super Contributor
timestamp: August 24, 2014, 09:54:55 pm
content: sharp memory lcds?http://www.sharpmemorylcd.com/aboutmemorylcd.htmlpixels will be too small but you can probably use more than one or use dithering to do a gradient.

author: wraper
author_rank: Unknown
timestamp: August 24, 2014, 10:03:54 pm
content: http://en.wikipedia.org/wiki/Flip-disc_displayAlso called electromagnetic (flip) dot display

author: zapta
author_rank: Super Contributor
timestamp: August 24, 2014, 10:04:13 pm
content: Quote from: djacobow on August 24, 2014, 09:47:05 pmThe kindle has such display. You turn it off and it draw some nice picture on the screen and goes to sleep. When it arrive by mail it has a large "Press Here" written on the display.

author: tom66
author_rank: Super Contributor
timestamp: August 24, 2014, 10:07:01 pm
content: The Kindle display is quite nice. A coworker has the damaged screen from someone's Kindle. The last image is still displayed in the top corner of the display, even after months of sitting. Neat technology.

author: djacobow
author_rank: Super Contributor
timestamp: August 24, 2014, 10:13:09 pm
content: Quote from: zapta on August 24, 2014, 10:04:13 pmYeah, and I seem to remember somebody on the forum had an e-ink dev kit that didn't seem too bad, either. Maybe it was Mike (of Electric Stuff?)There are a bunch here:http://the-digital-reader.com/2013/05/23/e-ink-dives-into-the-diy-market/#.U_pizVVX-uYI'll probably get one to play with, but there are two things I think are a drag. One, these are pretty small. Two, the display and control logic are pretty self-contained, so there's not much for me to do, other than send in bytes 4b at a time like an LCD.

author: zapta
author_rank: Super Contributor
timestamp: August 24, 2014, 10:17:46 pm
content: Check thishttp://www.adafruit.com/products/1316

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2014, 11:31:39 pm
content: How about the old-school airport arrival displays? Like old alarm clocks? You know, it goes trrrrrrrr-flip flip flip flip and it's like these numerals printed on half panels?Eh, I don't know what *those* are called either.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2014, 11:33:20 pm
content: ahhhhhhhhhttp://en.wikipedia.org/wiki/Split-flap_displayor how about even older stock market ticker tape???

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2014, 11:35:15 pm
content: ahhhhhhhhhhhhhhh #2

author: Wilksey
author_rank: Super Contributor
timestamp: August 25, 2014, 12:03:26 am
content: haha, I work for a company that design the drivers for those types of sign, in the UK they are known in the "industry" as rotating plank signs, they can be entire "planks" or multiple "flip dots" to make up a "plank".We did a trial on a digital version of the "rotating plank" sign, and I had a hand in the design of the display matrix, this was a few years ago now and it never took off as the signs themselves were upgraded to more advanced ones instead, but what we did for the trial was two different matrix designs, one had yellow led's and for the "rotation" it simply pushes the pixels down until the display is blank then moves another set of pixels down from above to give a scrolling effect, another option we did was we used RGB led's and we could create a range of colours as well as turning the display "off".If you wanted something that persisted the display then you would have to use something like E-Ink that the Kindle et al uses.

author: djacobow
author_rank: Super Contributor
timestamp: August 25, 2014, 01:56:29 am
content: Quote from: Alex Eisenhut on August 24, 2014, 11:33:20 pmYes, one of these would be so awesome. There is a display like this at the Ferry Building in San Francisco. Each segment can flip through all the letters, numbers, and a few symbols. It makes a very satisfying chunk-chunk-chunk sound while it's cycling through to the right letter.I would like to have a 2x16 one of these, maybe with 1" or 1/2" letter on my desk!!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 25, 2014, 02:53:09 am
content: Have you ever seen this old Tektronix numerical readout?http://www.wellenkino.de/matt/1S2/545B1S2.JPGIt's hard to tell, but that orange rectangle over that piece of plumbing is actually a display. It's a series of cutouts that are selectively rear-illuminated.It's nothing magical, it just displays the time base depending the switch position. It's quite pleasant.I think printing on transparencies with a laser printer might do it.

author: daqq
author_rank: Super Contributor
timestamp: August 25, 2014, 06:27:43 am
content: I've looked into something similar - e ink and similar seemed great for that, but it was shown as useless due to the operating temperature range, which needs to be within 0 to 50 deg C.