Looking for large segment LCD display

I'm trying to find a largish monochrome segment LCD

My goal is to make a wall display that shows real time departures for my subway stop.

So, I want the display to be large enough to read from across the room, and does not need to be backlit, sort of like a digital wall clock. All the segment displays I can find are tiny, though. Maybe I don't know the right terminology.

Anyone have any ideas where I could find a display that could fit my project?

By "segment LCD" do you mean "7-segment numeric" or an alphanumeric display (16 segment?)?

Ideally, how tall would you like the digits/characters to be?

How many digits/characters do you need?

What is your price limit?

You say it "does not need to be backlit" but would you be able to use an LED (lit) display? Alibaba.com lists several 1.5" 16-segment LED displays. Unfortunately the minimum order is 500 or more.

SparkFun sells a 6" tall 7-segment LED. COM-08530. But if this will be a battery-powered display, then LED is a big no-go.

For a more power-efficient LCD, I found this:

http://www.mouser.com/ProductDetail/Lumex/LCD-S101D40TR/?qs=Dsqf%252b7W9DRpOWhPDPCg34A==

...spendy though.

johnwasser: By "segment LCD" do you mean "7-segment numeric" or an alphanumeric display (16 segment?)?

Not sure, whatever's more convenient

johnwasser: Ideally, how tall would you like the digits/characters to be?

3 inches perhaps

johnwasser: How many digits/characters do you need?

Ideally two or three rows of 6 characters

johnwasser: You say it "does not need to be backlit" but would you be able to use an LED (lit) display?

Ideally not LED, because this is going to go in my room and left on all the time so I don't want it calling too much attention to itself or lighting up the room all night. Old-school unlit LCD makes more sense

johnwasser: Alibaba.com lists several 1.5" 16-segment LED displays. Unfortunately the minimum order is 500 or more.

I'm only making one of these for myself, so bulk ordering doesn't make sense

Here's a slightly cheaper 3" LCD:

http://www.mouser.com/ProductDetail/Lumex/LCD-S101D30TR/?qs=sGAEpiMZZMt7dcPGmvnkBtTTS6YQarUPClOgrMEkKXs%3d

EDIT: For some reason though, that 3" has 50 pins whereas the 4" I linked to above only has 8 pins. Weird. You might prefer the 4" just to avoid dealing with so many pins.

EDIT: If you decide to go LED, you can add an LDR/phototransistor and dim the display with PWM when the room is dark.

tylernt: SparkFun sells a 6" tall 7-segment LED. COM-08530. But if this will be a battery-powered display, then LED is a big no-go.

Doesn't need to be battery driven but if it's LED I would need to include a photoresistor to like turn down the brightness like 97% at night so it doesn't keep the room lit up, although this increases the complexity of the design

tylernt: For a more power-efficient LCD, I found this:

http://www.mouser.com/ProductDetail/Lumex/LCD-S101D40TR/?qs=Dsqf%252b7W9DRpOWhPDPCg34A==

...spendy though.

seems to be this: http://www.lumex.com/products/detail/4014

Yea, pretty expensive. Plus I assume the complexity would increase if I have to have a different display for each digit

comparisonmetrics: Yea, pretty expensive. Plus I assume the complexity would increase if I have to have a different display for each digit

Talking "raw glass" LCDs and LEDs, it doesn't really matter if you have a single 12-digit display or 12 1-digit displays. Both setups will require the same amount of complexity to drive and will typically involve a bunch of shift registers or multiplexing or both.

If you want to reduce complexity, you need an LCD/LED "module" that already has the driving circuitry built in and lets you talk to the controller via I2C, SPI, RS232, or a proprietary bit-bang protocol. However you may have a hard time finding a module in the size you want.

tylernt: If you want to reduce complexity, you need an LCD/LED "module" that already has the driving circuitry built in and lets you talk to the controller via I2C, SPI, RS232, or a proprietary bit-bang protocol. However you may have a hard time finding a module in the size you want.

Right. I'm just surprised that what seems to be out there to display a couple rows of characters is much too small to be seen from the other side of the room, so I was wondering if I was missing something

I think it's just a very niche market -- not profitable enough to have a wide selection of generic parts for you to choose from. Anyone wanting a big display just has one custom-designed by a LCD fab house and orders 100,000 of them. For example, I have a clock + indoor/outdoor thermometer hanging on my wall at home with 3" digits, but with a bunch of other unique glyphs it's definitely a custom job and not any kind of off-the-shelf display.

One more idea for you. EL (Electro-Luminescent) wire is popular amongst the folks that like to overclock their PCs and put them in glowing cases, which makes it somewhat inexpensive and relatively available. Making your own EL multi-digit wall display might be fun and cool, and possibly even cheaper than $15/digit.

EDIT: The EL wire itself isn't too expensive, but the drivers... ouch.

comparisonmetrics:

johnwasser: By "segment LCD" do you mean "7-segment numeric" or an alphanumeric display (16 segment?)?

Not sure, whatever's more convenient

You're not sure if you wan to display alphanumerics or only digits?!?

johnwasser: How many digits/characters do you need?

Ideally two or three rows of 6 characters [/quote] So 12 or 18 digits? The 3" LCD digits run $10 or more each so $120 to $180 or more for the LCDs. Then you will need segment drivers. You never mentioned what your budget was.

I'm starting to think that a big pile of 5mm LEDs hot glued to some foam board and placed behind a diffuser -- a DIY 7-segment, as it were -- is going to be the cheapest large display solution.

Like this, only smaller:

https://www.sparkfun.com/tutorials/47

You’re not sure if you wan to display alphanumerics or only digits?!?

Digits and and a character that can be used to indicate the direction of the train which could be made out of digit segments

So 12 or 18 digits? The 3" LCD digits run $10 or more each so $120 to $180 or more for the LCDs. Then you will need segment drivers. You never mentioned what your budget was.

$100 maybe? Unless I really fall in love with the design

I wonder how achievable it would be to cannibalize the display off a cheap wall clock, e.g., http://www.ebay.com/itm/75071T-Timex-Intelli-Time-Digital-Wall-Clock-13-5-Extra-Large-LCD-Display-NIB-/271394753105

Alternatively maybe I could come up with some way of representing it as arcs on a ring using a pixel ring

https://learn.adafruit.com/neopixel-60-ring-clock

Actually this might do it:

http://www.aliexpress.com/item/Standard-7-Segment-1digit-LCD-Panel/461081650.html

$3.60/ea seems like a pretty sweet deal to me! Heck I'm tempted to buy some myself, and I don't even have a use for them!

These appear to be bare-glass LCDs, so you will still need to drive them. An Arduino can produce the required 5VAC to drive them (DC will ruin an LCD), but if you multiplex the digits you shouldn't need an obscene number of pins -- even an ATmega328/32u4 like the Uno/Nano/Micro/ProMini might have enough. You need 8 pins for the segments (or 7, if you never want to display the decimal point) plus 1 pin per digit, hopefully leaving just enough for Wifi/Ethernet/Bluetooth to grab the train times with.

http://www.atmel.com/images/doc8103.pdf

It's inconceivable that someone hasn't already written an Arduino library for multiplexing bare-glass LCDs, but I didn't find any with a quick Google?