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Messages - markdpend

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OLEDs / Re: NHD-0420CW-AG3 Pixel Test
« on: June 04, 2015, 03:10:31 PM »
Thanks for the reply.  That's a great idea on the PIR sensor.  I already incorporated an LDR sensor in the latest model to turn off the display at night but replacing it with a sensor that can turn it off when no one is around is much better and also gave me an idea of triggering some sort of moving text when nobody's around to show it's on/working to equally excite, on average, all the pixels to help improve wear uniformity.  I wasn't aware of the OLED's built-in scroll feature, will have to look into that. 

Back atcha on the Karma.   ;D

OLEDs / Re: NHD-0420CW-AG3 Pixel Test
« on: June 03, 2015, 06:21:30 PM »
Well the problem went away as mysteriously as it showed up.  It's been sitting several hours unplugged since the first pictures were taken.  Pics below.  You can see some of the burn-in on this one.  So I ran the pixel test program on my other blockers and everything went fine.  If you have any more insight, I'll take it.  Thanks for the help once again.

So I have maybe a related question.  I have a plasma TV and it also suffers from burn-in.  Is that characteristic of "organic" technologies?  Is there another type of 4x20 character display technology with as good contrast as your OLED (character color-on-black background) that doesn't suffer burn-in, kind of like the way LCDs evolved?

And one more if I may.  How does one earn non-zero Karma?

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OLEDs / Re: NHD-0420CW-AG3 Pixel Test
« on: June 03, 2015, 03:11:57 PM »
Thanks for the quick reply.  Sorry, I had the wrong part number.  It's the NHD-0420DZW-AG5, not the slim one.  The displays are mounted in a plastic box.  All power (VCC) and ground is via connector pins 2 and 1 respectively.  I don't have anything electrically/directly attached to the bezel itself.  The power design is robust (VCC, GND), i.e. thick traces, star distribution, etc.  There is no earth ground as it runs on a 2-prong AC/DC adapter.  I work on a grounded bench.  These displays, however, didn't come out when I worked on the project as they're permanently soldered to another PCB so they never get touched.  This was just a software exercise for the display.  I have a PIC inside a ZIF socket that comes out when I make firmware changes.  I'm grounded when I do that.

Any connection to lighting up all the pixels?  The problem showed up right after doing that and it's been in use and trouble free for a couple of years.

OLEDs / NHD-0420CW-AG3 Pixel Test
« on: June 03, 2015, 05:04:28 AM »
Hi, I built a few projects using the NHD-0420CW-AG3 OLED display a couple years ago and am now refurbishing them.  I want to see if the displays have any issues so I wrote a small routine to light up every pixel (sent 0xFF) in every position (all 80), as shown below.   It was on for less than a minute about 4-5 times.   I found a little burn-in and only 1 dead pixel in only 1 character (row 2, column 15).  You can't see the burn-in but you can see the dead pixel in the picture.  So far so good until I turned it on a couple minutes later (normal operation) and find a couple columns of pixels that now won't turn off.  Hoping it might be a saturation issue that would eventually subside, I waited about an hour but they were still there and that's when I took the pictures.  So I have some questions.  Did I damage the display turning everything on at once?  If so, is it repairable with either component(s) change (I'm handy with electronics) or maybe a software approach?  If I did damage it, is there a preferred way to test the pixels?  I've got 3 more old units I want to test but am reluctant to try this again.  Thanks.

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Customer Projects / Re: Custom Call Blocker
« on: May 12, 2015, 04:00:38 PM »
Adding two pictures.  Removed the protective cellophane tape and shows a call from Newhaven.  Used a different contrast for the second picture, display color shows up much stronger while the blocker becomes darker.

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Customer Projects / Re: Custom Call Blocker
« on: May 07, 2015, 05:20:16 PM »
The following pictures illustrate how one can use Newhaven's NHD-0420DZW-XXX OLED 4x20 character OLEDs to display data in a 'bar chart' fashion.  Two pictures show the Number of Calls that came in by Month and Year.  The third and fourth pictures show the Number of Calls that came in by Time-of-Day.  The numbers are printed vertically which naturally get 'taller' as the number gets 'larger', i.e. with each factor of 10, another digit is displayed.  In the Calls by Month and Year 'plots', Years are separated using custom inverse numbers in the column between the months of D (Dec) and J (Jan).  Since this format uses the top row for the display title and the bottom row for the first letter of the month, that leaves only 2 rows for the actual number of calls. To accommodate numbers over 99 and to make this a little less busy, a small '1' was created, again as a custom character, and is inserted to the left of the column.  This can be seen in the Total Calls picture for March 2014 showing 102 calls. The high contrast of Newhaven's OLEDs makes this very easy to read. 

The Time-of-Day 'plots' are essentially histograms since all calls are sorted based on when they came in throughout a 24-hour day. Five time intervals are separated using custom inverse numbers in unused columns (thus three rows are available for numbers) and are interpreted as follows; the number between 09 and 12 is the number of calls that came in between 9am and noon (0900 and 1200).  The number between 15 and 18 is the number of calls that came in between 3pm and 6pm (1500 and 1800), and so on.  So the last number, which follows 21, is the number of calls between 9pm and 9am thus wrapping around back to the left at 09.

The high contrast of Newhaven's OLEDs makes this approach easy to read quickly and adds a little creativity to 'just' character displays.

The last picture is of a cheaper 4x20 LCD character display (not a Newhaven) as a point of comparison.  This may be similar to Newhaven's NHD-0420DZ-NSW-BBW.  It also looks pretty good but I prefer Newhaven's OLEDs and think the extra price is worth it.

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Customer Projects / Re: Custom Call Blocker
« on: May 04, 2015, 01:58:53 AM »

Thanks for the discount coupon.  I just bought 4 more OLED displays and saved some money.  I now have enough parts to build and sell another dozen or so, then off to the next hobby unless this blocker takes off.  Everyone really likes these OLED displays, the black background with yellow/green/blue font looks really clean and crisp - although I'm having some trouble with the blue one but one of your coworkers thinks it's a humidity issue.  Thanks again.


BTW - I was not able to reply to your personal message.  It showed User 'Bridgette_E' has blocked your personal message.

OLEDs / Re: NHD-0420DZW-AB5 Pixel Issues
« on: April 23, 2015, 01:33:39 PM »
Thanks for taking the time to help.  Several buttons failed early too which could corroborate humidity is the culprit.  I'll see what I can do about sealing it better.

OLEDs / Re: NHD-0420DZW-AB5 Pixel Issues
« on: April 22, 2015, 10:05:17 AM »
It's hooked up in 4-bit parallel mode.  Pins 1-2 are VSS and VDD respectively.  Pin-3 is NC.  Pins 4-5-6 are control pins RS, R/W, and E.  Pins 7-10 are NC.  Pins 11-14 are data pins DB4-DB7 driven from a Microchip PIC18F4685.  Pins 15-16 are NC.  Picture below.  VDD is 5V.  Unit is in someone's house, probably in the kitchen/eating area.

Update: I got in touch with the original owner. "It had been left in a room that was designed as a bedroom but, never used as such rather, an office.  I should say the ambient temperature in the room has consistently been fairly warm during the heating season, being in Boston.  The room is in a late 19th century building which uses a steam radiator heating system.  Even with radiators turned off, pipes going through the walls leading to other floors radiate a good deal of heat causing a steady ambient temperature of least 80 degrees."

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OLEDs / NHD-0420DZW-AB5 Pixel Issues
« on: April 21, 2015, 09:40:01 PM »
Hi,  The attached picture is a display about a year old.  The individual pixels are beginning to fade at random places.  Does anyone know if this is typical wearout for this technology?  Thanks in advance for any help.

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Customer Projects / Custom Call Blocker
« on: April 21, 2015, 12:23:21 AM »
I used Newhaven's NHD-0420DZW-XXX OLED displays (4x20) to make a custom call blocker.  The displays are very nice.  Below are yellow and green.  In two of the pictures, you can see custom icons that were easily made for this display.  Having color on a black background makes the display very sharp and especially crisp at night.  All have excellent contrast and are easily read in full daylight.  Because of the posting size restrictions for pictures, I had to downsize all of them and some appear more blurry than they actually are.  In addition, all of the displays still have their protective plastic cover.

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Hi, What happens if one does connect pin-2 to VDD?

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