hacking lcd displays price

Light from the single LED is collimated with some Fresnel lenses. That light passes through an LCD panel, and from there the image bounces off a mirror and through a focusing lens housed in a spiral guide. Focal adjustments are made with a small lever, and the whole assembly provides just enough friction to prevent the lens from moving out of focus on its own.

Looking to take your project to the next level in terms of functionality and appearance? A custom LCD display might be the thing that gets you there, at least compared to the dot-matrix or seven-segment displays that anyone and their uncle can buy from the usual sources for pennies. But how does one create such a thing, and what are the costs involved? As is so often the case these days, it’s simpler and cheaper than you think, and [Dave Jones] has a great primer on designing and specifying custom LCDs.

We’re amazed at how low the barrier to entry into custom electronics has become, and even if you don’t need a custom LCD, at these prices it’s tempting to order one just because you can. Of course, you can also build your own LCD display completely from scratch too.

Thus, say you have a 128x64 STN LCD, you might accidentally try to drive it with a 64x64 input signal, and... in most cases I"ve run into it"ll work. The image will be displayed at the left, and the right 64x64 pixels will display whatever garbage was in those registers from power-on/reset (and if you believe the hype, those liquid crystals might get unhappy with DC... but, I"m not sure about that, since the AC waveform is separate from the shift-register loading).

The latter is something I"d been trying to figure out for some time, two displays on a lappy from the single display"s input. I don"t know why, but my brain was stuck this whole time in trying to use the regular input signals, rather than tapping to/from the panels themselves.

Or maybe you dug out a groovy old stencilled LCD from an old lappy with a HD activity indicator, battery indicator, etc. and want to mount it next to the display. Or even a VFD for such things.... oooohhhh....

Most LCD monitors have two films on the glass - a polarized one to filter out the light you are not supposed to see, and a frosted anti-glare film. The anti-glare film we don"t need, the polarized one we do - it is used for the glasses.

Print a full screenshot of the spreadsheet and taskbar onto a piece of thin, clear plastic. Convince people you can only see well with black and white, so you can make it a real high contrast print. But make sure any lines are thin. Apply this to the LCD, taking care to remove bubbles. Tehn jsut get uesd to seneig waht it looks lkie knid of srecwed up. The brain is amazing at adapting, and there is a good chance you read the last sentence naturally. Look again ^^.0

It"s pretty easy to do and only requires basic tools like scissors and an X-Acto knife. You can order the polarized filter online and just use an old LCD monitor you have lying around.

The transparent display we offer for sale (CFAL12856A0-0151) is an OLED (Organic Light Emitting Diode) display. OLED displays produce images by emitting light in the corresponding color. To produce black in a normal OLED, the pixels are simply turned off. With the transparent display, if the pixels are turned off, the display is transparent rather than black.

We’ve heard from a few customers requests for transparent displays with black graphics as well as requests for larger transparent displays. This guide will walk you through creating a transparent display out of a graphic LCD.

Even further, a Chinese colleague hinted that they will never sell to you if you are doing anything in the consumer space (except you are one of the big e-reader makers of course). And that the traditional display companies could retool pretty quickly to make e-ink instead, but won"t. It"s all very very odd to me. I would suspect a cartel, but it doesn"t make any sense - e-ink is too slow and to ugly to really cannibalize laptop and monitor sales. We had good use cases: industrial PCs, outdoors informational displays, and so on. But apparantly not good enough for e-ink.

As it stands though, LCD and probably OLED will overtake any use cases that e-ink would have had. The company behind e-ink dropped the ball there, thinking too highly and too exclusively of their own product. It"s not that fancy, like, bruh.

"Secret sauce that tells you how to drive the display cells"? You mean like a voltage table that is also present inside every LCD or OLED? The difference would be that the electrophoretic display would need a much bigger table so it would have to be kept on the SoC since it can"t possibly fit into a single voltage driver circuit. That"s not software, that"s just a big table of voltages that"s hardcoded for each unique panel. Is that what you think is "secret sauce"? Do you also want to extract that table inside each LCD drive circuit as well? I guess you could use it to make your LCD or OLED panel show brighter colors but at the risk of burning and damaging the crystals. I imagine the same risk would also be true for electrophoretic panels or anything where you can change the physical voltage that is being applied to the material.

Larger displays, suitable for advertising, marketing, or other commercial/industrial applications are much more expensive, as noted here. Some of that is likely cost-driven, but another element is that if a larger supply were offered, the price would fall. Absent some way of bracketing specific applications, there"s little to keep, say, advertising or commercial users from making do with cheaper consumer-grade displays.

Hypertext and sequential text do not need scrolling - we have paged since forever. And when the user wants, scrolling is available and perfectly usable with EPD. Slower than LCD? Well LCD has a number of properties inferior to those of EPD: if you have no use for these, why should you use EPD? Clearly the balance determined by all properties changes according to use case. This is really basic.

Very trivial principle, contextualize it - it can be applied to CRTs and brass plaques: there exist a number of properties for two or more technologies; some use cases will turn the balance in favour of A, others in favour of B etc. You will use a hammer when it is appropriate to use a hammer, and a screwdriver when it is appropriate to use a screwdriver, and you will do just like Ben Franklin recommended and "saw with a file and file with a saw when pressed". Again, all of this is as trivial as reasoning comes; to make the reasoning productive (and debatable), you have to add the uncommon assumptions, not the foundationals. You have confirmed the opposite point: just refer your statement to LCD!

Someone definitely flunked the messaging on this one, and I find it very disappointing :( The key advantage to an e-ink style of display is less eye strain, because you aren"t staring into a bright light source that refreshes 60 times a second. (And battery life, of course; you can put your book down and forget about it until later). And that this limits the device is fine: a lot of people do a lot of reading! People like reading! Alas, as more and more people grow up reading all sorts of things on LCDs, so the inconvenience and the discomfort is just a normal part of reading for them, that becomes a much harder sell.

LCDs update 60 times per second (or more… 120 Hz displays are becoming more common) but they don"t flicker the way CRTs used to, so there"s no reason to think this would contribute to eye strain. Brightness could be an issue but you can just lower the brightness of the screen to match the surroundings.

Some displays do this as a feature though (known as backlight strobing, motion blur reduction, etc.): LCDs take time to transition, so if you keep the backlight on at all times, you"ll potentially see blurring from persistence of vision while the display is mid-transition. Instead, you can turn the backlight off until the screen has transitioned and then turn it back on so that you never show a partially transitioned image.

Since it is very well readable in full sunlight, e-ink is very suitable for low refresh aircraft displays. I suspect the same could apply for all kinds of HMIs which are used outdoors.

In my experience e-ink displays reduce eye strain and attract less attention. This results in more attention being drawn to the outside world, which in turn is a good thing for safety.

Maybe the eink displays refresh fast enough to make this be a minimal issue, but my few years old Kindle Paperwhite doesn"t have me confident that"s true.

Color e-ink has a killer app: Changeable photo display in homes. This is much harder to achieve with alternative technologies (any display emitting light is an immediate no-go for just hanging on your wall). In contrast, e-readers have a significantly smaller advantage over the alternative of just reading on your phone or tablet, yet that seems to have been enough of a market for them to become cheap. And unlike e-readers, where you only really need one per person, there is hardly any limit to the number of displays people would put in their home if they do not emit light, have nice UI, and are cheap.

People have tried changeable photo displays before, with LCD or whatever. Of course, these require more power, but they are plugged in devices and I"m not convinced non-technical people think about the power consumption of their devices outside of really niche situation where everyone knows they supposed to care (large appliances like washing machines). And, even the best e-ink screen looks kind of washed out when displaying color, right?

But I can’t really find any other large format e-ink displays with the driving hardware (which can be even pricier than the display), so I’m inclined to believe him.

I believe the monochromatic electrophoresis displays by E Ink had higher reflectivity and lower price, which is what mattered for e-readers, so all the others went out of business.

In the 00s, there were reflective color LCDs in things like phones and portable game consoles. The kind that isn"t black when off. Why is this technology not developed further any more, and all modern color LCDs rely on backlight? If it"s a dead end, why?

On top of the e-ink IP stronghold, I think there is also a Product manager issue in consumer electronics. Everyone wants to show case Macbook-esque glossy displays whereas a large number of consumers want displays that they can use outdoors and without eye strain. Everybody complements garmins transflective displays but somehow nobody makes the leap of slapping them on phones or laptops.

In general, I find e-ink displays relatively expensive for modestly sized ones (say 6 inch +). What"s some of the best deals/value for e-ink displays for some personal projects? Broken e-readers for parts?

For larger ones, I think the best option is something like a recycled kindle. There was even a post on HN a few months ago from a company selling Kindle displays hooked up to breakout boards (may have even had on-onboard microcontroller, like an ESP-32?)

As you probably know, bistable or passive displays like the E-Ink ones in e-readers focus on battery life and readability rather than color and interactivity. The latest devices have been optimized for fast page refreshes and touch operation, but generally you’re still waiting a half a second or so for the screen to flip over to the next page, menu, or what have you.

The possibilities for this generation of readers are limited: few people are going to install a hack like this, and even if they did, not much content is really designed to be consumed this way. Pages are a natural way to read books, and scrolling constantly is kind of a pain. But it’s amazing to see these displays, usually so slow and static, being used so actively. Here’s hoping the next displays from E-Ink (or Bridgestone, or whoever) are capable of even more. Despite what people might say, the passive display still has a lot of potential to grow and evolve.

The first step in the hack is to select a compatible LCD that’s also conveniently available. For various reasons related to how the flat panel display market works, LCDs are difficult to purchase in their raw form. Fortunately, Mouser Electronics has a fair selection of LCD modules available and in-stock, although the price is no where near wholesale. I found that the Microtips MTF-TV57NP721-AV was a good match; you can buy these directly from Mouser for $150.80 by ordering part number 668-MTF-TV57NP721-AV. This LCD module uses a compatible signal format, has an LED backlight that works with a slightly modified chumby backlight driver, and also features a 4-wire resistive touchscreen, which is exactly the technology used by the stock chumby device. While the datasheet for this display is not available for convenient download, the datasheet itself is not marked proprietary or confidential, so I was able to secure a copy with a phone call to the local Microtips sales representative.

The next step is to build an adapter board between the chumby and the LCD. The adapter board is necessary because the flat-flex connector used by the Microtips LCD has a different size and pinout from the existing chumby LCD connector. The design of the board doesn’t require many components, as it is just rewiring the signals between two connector formats, but getting the design right does require attention to detail. It’s particularly important to make sure you get the location of the connectors right, so as to minimize the stress on the flex cables, and you need to be aware of the pinout inversion that happens between the two sides of a flex cable mating to the same type of connector: pin 1 goes to pin 50, and vice versa. Here is a link to the schematic for the adapter board, and a link to the gerbers.

Since you won’t need the old LCD anymore, loosen the two long Philips screws on the wifi riser assembly and liberate the core from the LCD/bezel assembly by detaching the two flat flex cables that connect to the core board. Save the wifi riser assembly, screws, standoffs and cables. Also leave all the thermal pads in place; they will hold on their own if you do not peel them off of the circuit boards.

You will need to do some minor rework to the core circuit board of the chumby in order to beef up the backlight driver to work with the more power-hungry backlight of the larger LCD. The original chumby backlight is a 10.2 volt, 40 mA 3-LED backlight. The backlight inside the Microtips LCD is also a 10.2 volt backlight, but it requires 200 mA. Fortunately, the boost converter used to drive the chumby’s backlight has a current switch capable of handling that magnitude of current—the TPS65101 has a 2.3A switch in it. However, some of the external circuitry has to be upgraded. In particular, the catch diode D502 has a forward current rating of 0.5A. While the LCD only draws 200 mA, it is a boost converter so the amount of current going through the catch diode is going to be a bit bigger than the ratio of the output voltage to the input voltage times the average current. Therefore, D502 has to get an upgrade to a footprint-compatible but higher current version, such as the 1A-rated MBRX130TP by Micro Commercial, or the 1.5A-rated RB070M-30TR by Rohm. Finally, in order to actually increase the amount of current pumped into the LCD, the current sense resistor in the feedback network of the boost regulator has to be modified. R524 programs the backlight current in the “on” state of the backlight, though the following relationship: I = 1.146V / R524. Its stock value of 57.6 ohms yields a current near 20 mA; replacing this with a 5.6 ohm resistor will yield a current just over 200 mA.

Now that you’ve got all the bits and pieces, it’s time to put it all together. It’s good practice to mount the pieces so that they aren’t “floating”; the flat flex cables are fragile, and they will easily strain and break if you move the unit around too much. If you have access to a laser cutter, you can build the LCD mount using the designs presented below.

Next, cut a second protective bezel using 1/16” clear acrylic using the reverse bezel pattern. This pattern also has alignment markers on it, which are important for making sure the LCD’s active area is centered in the opening of the bezel. There is no need to treat the reverse bezel with paint because it is simply a protective layer to protect the painted front bezel from chipping and scratching.

A set of gaskets are applied to the outside of the LCD along the silvery circuitry area of the touchscreen panel in order to improve the touchscreen’s robustness against heat warpage of the acrylic that can cause the bezel to inadvertently touch down onto the screen. The gasket material in this case is Poron, but you may also use a couple layers of thin-cut pieces of masking tape to create a small offset between the bezel edge and the display.

Before screwing the backplate in place, attach the 33-pin flat flex cable (that you previously made by cutting down the 36-pin cable), and connect the other side to the adapter board; at this time, also connect the 4-pin touchpanel cable and the 50-pin cable for the LCD signals to the motherboard. Then, fold the adapter board assembly over and screw it in place using 4x M2x6mm socket cap screws.

You’re almost done! Flip the LCD assembly into the bezel, using the alignment pattern on the bezel as a guide, and glue the four LCD mounting corners in place, paying attention to ensure that the holes on the mounting corners line up with the holes on the back plate (you can accidentally put a mounting corner on upside down and have the holes end up on the wrong edge of the LCD). Standard super glue works well for this application. Allow the glue to dry for at least a half hour before proceeding.

The kernel contains the code that initializes the video frame buffer’s size, so the timing needs to be programmed into these registers by modifying the kernel source. Here is a patchfile that you can apply to the 1.5.0 kernel (build 565) that performs the appropriate initializations. The patch modifies one of the clock registers inside the MX21 to increase the frequency of the clock feeding the LCD controller, and it also modifies the LCD controller registers itself. It also patches code that handles copying the initial logo screen from a staging area in RAM to its final location. It’s more involved to get the bootloader to behave properly and show a more elegant startup screen; here is a link to the modified bootloader source. This code replicates the QVGA bitmaps stored in the bootloader four times over inside the VGA frame buffer for the chumby, and it handles some other corner cases during the hand-off between the bootloader and the kernel at higher resolutions as well.

Finally, reboot while holding down the touchscreen so that you enter the “Special Options” mode. When the selection screen comes up, you should be able to log in via the serial console and execute the command “update.sh USB”, which will overwrite the bootloader and the primary kernel with the code patches mentioned above. For safety reasons, the backup partitions’ kernel is not modified by the dongle, so you always have a safe partition to return to for re-flashing a broken chumby. The graphics on the screen will look funny in this mode, but it’s not harmful for the LCD.