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36 votes
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Mysterious LCD interface without wires

The little piece of rubber you removed IS the connector. Elastomeric connectors look like a piece of rubber and are commonly called "zebra stripes" because the conductive carbon stripes in the ...
JRE's user avatar
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25 votes
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Do LEDs require more power to function as they age?

The problem you are seeing is related to the construction of LED backlight circuits which require lots of LEDs. Often on poorly designed or "cheapo" designs there are LEDs or series strings of LEDs ...
Michael Karas's user avatar
22 votes

Why doesn't the switch command in this code work?

I didn't inspect the whole code but you forgot the "break" statement for each "case" : without it your code will perpetually exit the switch statement by executing "case 9&...
Genorme's user avatar
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19 votes
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No PSB pin on LCD?

Many LCD controllers (including the ST7920) can support a variety of interface types, of which you can use one at a time. Sometimes the interface type is fixed on a given LCD display module; sometimes ...
SamGibson's user avatar
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17 votes

What are rubbery, conductive strips called on the sides of an LCD screen?

As others note it's a "zebra connector" which conducts through the plane of the rubber but not across it (ie in the directions you'd expect for it to work). The 'pitch' of the band s of conduction/...
Russell McMahon's user avatar
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16 votes
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How does 13 connections control a simple LCD with 34 segments?

Liquid Crystal material, the compound inside an LCD that reacts to electrical stimulation, likes to have an AC waveform to activate. So a single pixel would have two transparent electrodes with this ...
Adam Davis's user avatar
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16 votes

How does 13 connections control a simple LCD with 34 segments?

It takes the right signals on both the top and bottom glass to "light" a segment (actually turns it dark, tranparent is the not-see case). This allows LCDs to be arranged somewhat in a matrix. A ...
Olin Lathrop's user avatar
16 votes

Is it possible to drive a 2 X 16 LCD display using logic gates? (Without computer)

It is possible to make a circuit out of logic gates that would be able to initialize and display characters onto a 16x2 LCD character mode module. It is also possible to make a circuit out of logic ...
Michael Karas's user avatar
13 votes

How much current does an 1602 LCD draw?

Typically the LCD driver draws around 1mA or 1.1mA, not counting the external contrast voltage divider. They are fairly consistent between suppliers, as they are mostly based on an (originally) ...
Spehro Pefhany's user avatar
12 votes
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So there was an ant that somehow got inside my screen. How do I remove it?

The black metal bezel around the LCD glass is what connects to those bent fingers. The bent fingers either capture the LCD circuit board in place from its edges or the fingers extend through slots in ...
Michael Karas's user avatar
11 votes

Why do LCD screens need to refresh in the first place?

Some modern LCDs (especially ones built into phones and laptops) do kind of work this way; it's called "panel self refresh", which means that the display has its own memory that stores the ...
hobbs's user avatar
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10 votes

Powering Arduino from a voltage divider

You shouldn't power anything from a voltage divider since the output voltage will fluctuate greatly with the amount of current sourced. Rather you should look into a step down voltage regulators. They'...
Gunchars's user avatar
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10 votes

Do LEDs require more power to function as they age?

Yes, even LEDs do not have an infinite lifetime. However, when run at a low enough power such that they do not heat up much a lifetime of 50000 hours can be expected. 50000 hours when operated 24 ...
Bimpelrekkie's user avatar
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10 votes
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How does a microcontroller drive an LCD?

At some level a 320x240 display usually has 320 row drivers and 240 column drivers. These drivers are almost always provided by chips integrated into the displays (often on flex PCBs around two edges ...
Dean Franks's user avatar
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10 votes
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How exactly is an LCD damaged by DC current?

A LCD segment consists of a cell filled with liquid with very thin transparent electrodes on either side. If a DC voltage is applied to this metal is transferred from the anode to the cathode ...
RoyC's user avatar
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10 votes
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TFT LCD Tear-down Silver Rectangle Question

That "silver rectangle" is the LCD driver chip. The silver color is the back of the chip-die which is made of silicon The function of that LCD driver chip is to take some input signals and drive ...
Bimpelrekkie's user avatar
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9 votes
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Can zebra strips (elastomeric connectors) be cut to size?

Zebra strips are most often custom made to size to suit the enclosure design requirements of a product designer. This is why it can be hard to find general purpose replacements. Using the following ...
Michael Karas's user avatar
9 votes

Mitutoyo LCD repair

Figure 1. An LCD connector. Units are cm. Look closely for the stripes in the middle layer. Source: Elastomeric Connector. The elastomer strip is known as a "zebra strip". It has a sandwich ...
Transistor's user avatar
  • 176k
8 votes

Why do LCD screens need to refresh in the first place?

The whole reason is the component circled in red below (Cs) which is a capacitor. Capacitors are really easy to manufacture, you only need two conductors and to space them apart with an insulator or ...
Voltage Spike's user avatar
  • 82.8k
7 votes

Is it necessary to use resistor when connecting backlight of 16x2 LCD display?

This is just a complementary answer for people facing this question for the first time (beginners or even non-beginners), like I did a few months ago when received a batch of no-name LCD modules ...
MV.'s user avatar
  • 278
7 votes
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Can't understand where backlight pins are in this LCD module

connections are just 14 pin, and backlight is not mentioned The backlight LED connections are not on the same connector. They are on the opposite side of the module. (drawing from p.7 in the ...
Nick Alexeev's user avatar
  • 38.2k
7 votes
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Why are multiple bias voltages required to drive an LCD?

The voltages between BP and SEG for each segment need to fulfill two conditions: The average voltage over the duration of the frame must be 0 (= no DC) The RMS of the voltage must be high when we ...
AndreKR's user avatar
  • 2,999
7 votes

Is it possible to drive a 2 X 16 LCD display using logic gates? (Without computer)

Yes. You'll need several blocks to make it work: You need an LCD driving block. The LCD is intended to be written to in 4 bit or 8 bit mode, I recommend 8 bit for this application. Each write ...
Adam Davis's user avatar
  • 20.5k
7 votes

Why do we need to continuously refresh a high resolution graphics LCD while we don't need the same for a character LCD?

All LCDs require refresh. On the character displays, this is usually hidden from you - you're not connecting directly to the LCD segments, there will be a driver chip intermediating. This can remember ...
pjc50's user avatar
  • 46.7k
7 votes

Are all pixels addressed simultaneously in one frame?

There are different technologies used for "computer screens". Today's most common technology is TFT-LCD which mostly uses the Active Matrix adressing scheme to build up an image. ... is ...
Bimpelrekkie's user avatar
  • 80.9k
7 votes
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How can I re-assemble this cheap scale's LCD display?

The rubber strip has many parallel conducting wires across it, and will connect a set of contacts on the PCB to a set of contacts on the LCD display. Place it properly between the PCB and the display ...
ocrdu's user avatar
  • 9,230
6 votes

What is the acceptable current draw on pin #9 on a VGA connector?

VESA have made a lot of their standards freely available, so we can finally find out what the standard actually says. The following is from "VESA Enhanced Display Data Channel (E-DDC) Standard ...
poizan42's user avatar
  • 161
6 votes
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LVDS 30 pin cable confusion

First of all set 3.3V supply voltage with jumper, as @Andrew Morton wrote in comments. Connect signals in the following manner: All pins marked VSS on LCD (1,10,13,16 and 19) to GND LCD supply VDD (...
Jakub Rakus's user avatar
  • 2,235

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