Blue light rant - Page 1
Forum section: electronics / general

author: Rick Law
author_rank: Super Contributor
timestamp: January 31, 2015, 02:23:56 am
content: Ok, this is just the run of the mill below 30Volt rant...Anyone uses one of those Nokia5110 LCD display? Have you tried to use those with a blue back light?That damn blue back light is driving me nuts. I have an Adafruit one (white back light) and it got "assigned" to a circuit that I use regularly, regular enough that I want to have a back up in case I blew it when I experiment with it. So, I ordered a Chinese made one as backup.Not noticing the detail, this one has a blue back light. It works fine except when that damn blue back light is on. It makes what is a clear and good contrast display into something that is so damn difficult to read.Did they even spend a moment looking at that and try to read the display? Who in the right mind would use something like that as back light.Gosh... this stupid blue back light is really really really stupid...

author: george graves
author_rank: Super Contributor
timestamp: January 31, 2015, 02:47:05 am
content: I noticed that china is making a "replacement" version of the 5110 with out the rounded off bezel (and maybe better lighting?)http://www.ebay.com/itm/1x-1-44-inch-Serial-128-128-SPI-Color-TFT-LCD-Module-Arduino-Instead-Nokia-5110/321538122333I can't find a picture of it lit up and working though.Also - on the original 5110 the LEDs are easy to change in a pinch.

author: Rick Law
author_rank: Super Contributor
timestamp: January 31, 2015, 03:04:59 am
content: Quote from: george graves on January 31, 2015, 02:47:05 amYeah, after getting really annoyed yesterday, I pop the LCD cover and saw the 4 led. I covered it with yellow tape making it into green, it was much easier to read but much dimmer. (And I don't have the current to drive the led's brighter.)I was going to get some white led's to replace it. I could get 4 led from Mouser for $2.50, or get 20 from eBay for $2.10 - either way, I feel silly spending $2+ on led's to "fix" something that was purchased for merely $2.40.This is just backup in case I blew the existing one which is white backlight. I may just live with it -or- perhaps do it just to get more practice with SMD replacement. Either way, this whole blue light fad just is so damn silly.

author: sleemanj
author_rank: Super Contributor
timestamp: January 31, 2015, 03:21:43 am
content: Buy an 0805 LED assortment from aliexpress for a couple buckshttp://www.aliexpress.com/w/wholesale-0805-led.html?iSortType=total_tranpro_desc&SearchText=0805+leduse 4 white, put the rest in your parts drawer.

author: miguelvp
author_rank: Super Contributor
timestamp: January 31, 2015, 03:25:11 am
content: My only problem with the blue back light displays is that they don't photograph that well. I can adjust it fine for my eyes, but taking a picture it washes it off.In this picture I had to adjust the contrast so it will show up in the picture, but it does look better in real life. Maybe is about the angle and my lighting in my home office.

author: TMM
author_rank: Frequent Contributor
timestamp: January 31, 2015, 06:12:27 am
content: Quote from: miguelvp on January 31, 2015, 03:25:11 amThat's not blue LED backlighting like the OP is complaining about, that's white LED backlighting with an inverted LCD. The LCD lets more blueish light through which is why it appears blue.It you invert the polarising filter on the LCD you'll get a white background and dark blue/purple pixels like this, which is quite nice on the eyes:What the OP is talking about is this (non-inverted LCD, blue LED):Much harder on the eyes.The difficulty in photographing both types comes from the brightness of the display. To preproduce the blue colour of the display in your photographs you need to turn the exposure down, which will make the rest of the scene dark. What you can do is take two photos - one at normal exposure and one at low exposure, then copy and paste the display from the low exposure photo into the normal exposure one:

author: dannyf
author_rank: Super Contributor
timestamp: January 31, 2015, 12:24:38 pm
content: Quote5110 displays come in 3 colors, blue, white and rarely so now yellow. 7110 displays came in primarily yellow in the early days.I generally dislike led backlighting on lcd displays. They typically don't aid readability and consumes lots of power/current. The good reflective display is perfectly fine for me.

author: Rick Law
author_rank: Super Contributor
timestamp: January 31, 2015, 07:30:20 pm
content: Quote from: TMM on January 31, 2015, 06:12:27 amExactly...I wonder if the engineer/marketer who decide to make/sell these blue ones ever looked at them. It is so darn difficult to read it just made the thing so much less user-friendly.When the back-light is lowered instead of driving at max, it is even worst. To keep to what the FT232RL can give me (50mA@3.3V), I have the 4 LED's at about 20mA total. With the white led, I had no trouble reading it.With the blue, at full (about 200-240mA for four), it is difficult to read. At the 20mA (for white), it was unreadable. I increased it to max I can give in that circuit - about 35mA and the blue is still almost unreadable.I really wonder did they ever looked at the thing before finalizing the decision to make it with blue.

author: KJDS
author_rank: Super Contributor
timestamp: January 31, 2015, 07:43:55 pm
content: I read the title and thought it would be about badly driven police cars, or people failing to spot an ambulance.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 31, 2015, 10:59:53 pm
content: Quote from: KJDS on January 31, 2015, 07:43:55 pmMy first thought was K-mart

author: Rick Law
author_rank: Super Contributor
timestamp: February 11, 2015, 01:45:49 am
content: Ah, nice ending to a story.I would have felt silly if I was to spend $2 for a bag of (20) 0805 SMD led's from China to fix a $2 board; and on top of that, wait over a month for the LED's to come on economy shipping.So, this would have waited and waited and waited until I have other SMD-LED needs worth while of that wait, all the while, I get annoyed looking at that stupid blue back light and kick myself for not minding the details (yeah, blue back light was in the eBay listing details).A forum member here saw my dilemma and generously send me a few white LED's. Thanks to his generosity, this Geeetech (yeah, I spell it right) unreadable blue back-lid display is now a very readable white back-lid display! It is every bit as readable as the Adafruit Nokia display I have.Thanks you to this (per his request) unnamed member, I am a happier person than I was yesterday. My legs are having a good rest not having to kick myself.RickEDIT - removed a LOT of blank lines - probably stuck key. No wonder it was taking forever to save and I left the machine.

author: codeboy2k
author_rank: Super Contributor
timestamp: February 11, 2015, 08:19:06 am
content: 'da hell! a sea of blue in the blue light rant

author: TerraHertz
author_rank: Super Contributor
timestamp: February 11, 2015, 10:09:18 am
content: Fell asleep on the Enter key?Nobody seems to consider that those blue-lit displays may be on the market cheaply precisely because they are unreadable. I wonder how many they made?Black text on blue background is unworkable for me too. Anyone remember the early Web days, when for some reason there were people who'd have their site in blue-on-black, or vice versa?

author: Rick Law
author_rank: Super Contributor
timestamp: February 11, 2015, 04:51:20 pm
content: Quote from: TerraHertz on February 11, 2015, 10:09:18 amEdited original and removed the blank lines. Probably stuck key or something that added all the blanks. No wonder it was acting so slow at the time.Quote from: TerraHertz on February 11, 2015, 10:09:18 amProbably not... competing brands at the same price had white led's. I think there was a blue light fad in China for a while.

author: funkyant
author_rank: Unknown
timestamp: February 11, 2015, 05:44:33 pm
content: A little off topic, but kinda the same. I've also had enough of overly bright blue LED's being used just about everywhere. Why does every indicator light have to be the most ridiculously brightest, bluest light possible? Even the power light on the front of my TV! I'm pretty sure I can tell it's on without a massive blue searchlight probing into my living room.I'm ready for a green LED renaissance./rant over

author: Phaedrus
author_rank: Frequent Contributor
timestamp: February 11, 2015, 06:03:18 pm
content: Quote from: funkyant on February 11, 2015, 05:44:33 pmWell, herp, the LED datasheet says forward current 20mA. I guess I'll just pick my dropper resistor to give it 20mA then! Heck, let's make it 25mA for good measure.

author: rdl
author_rank: Super Contributor
timestamp: February 11, 2015, 06:25:53 pm
content: Yeah, I'm pretty sick and tired of overly bright blue LEDs on everything.My old TV had a blue LED, it wasn't all that bright and the designer did an awesome thing, the LED only came on when the TV was plugged in and on stand by, as soon as you actually turned it on, the LED went out. My new TV came with a green LED that comes on with the TV. It now has a piece of black tape over it.Anyway, on my own projects I tend to use reddish-orange LEDS because they remind me of old school neon pilot lights.

author: funkyant
author_rank: Unknown
timestamp: February 11, 2015, 06:33:12 pm
content: Haha, my TV has the bit of tape too.I also love the old school look of green and orange leds. Blue is so, SO overdone.

author: tszaboo
author_rank: Super Contributor
timestamp: February 11, 2015, 07:02:33 pm
content: Quote from: TerraHertz on February 11, 2015, 10:09:18 amSome years ago, I was sitting at the university, Ergonomics class. There were some slides on the projector, with these color background. I could not read it, made a half loud comment about it.Of course the slide was explaining the readability of texts against background. And the teacher heard it. What came after was only a little bit embarrassing...

author: Rick Law
author_rank: Super Contributor
timestamp: February 12, 2015, 12:44:05 am
content: Quote from: rdl on February 11, 2015, 06:25:53 pmQuote from: funkyant on February 11, 2015, 06:33:12 pmAh ha! I am in great company! My laptop wifi switch has an over-aggressive red on-indicator. I have a tape over that!I too prefer the orange. It reminds me of an old plasma display in the 70's. Any one here used a PLATO terminal before? The kind with the build in slide projector, 640x640 display...

author: TerraHertz
author_rank: Super Contributor
timestamp: February 12, 2015, 05:05:55 am
content: Rather than covering stupidly bright blue LEDs with tape, why not attack with the very aptly named blu-tak?Place a small dot of it over the LED, then make a pinhole through in the center. You can adjust the pinhole size to get the amount of LED light you want. Like these HD lights on my PC. Yep, it looks crappy, but it's better than having your eyes burned out.

author: funkyant
author_rank: Unknown
timestamp: February 12, 2015, 10:28:34 am
content: Lol. Also a paint marker like a Posca does the trick nicely. But I slapped the tape on the telly the day I got it, and it hasn't bothered me since

author: Neilm
author_rank: Super Contributor
timestamp: February 12, 2015, 06:56:20 pm
content: Quote from: funkyant on February 11, 2015, 06:33:12 pmMy TV has a nice red light when it is off. Fortunately, it also has an option in the settings to disable same.

author: SArepairman
author_rank: Frequent Contributor
timestamp: February 13, 2015, 04:56:32 am
content: I put a layer of kapton orange tape over offensive blue things. It makes it far more tolerable but still readable.

author: Rick Law
author_rank: Super Contributor
timestamp: February 13, 2015, 06:54:38 am
content: Quote from: SArepairman on February 13, 2015, 04:56:32 amI tried that - 1 layer didn't do it. With 2 layers, the color became ok, but it got too deem to be readable.I am glad at how well it worked out with the white SMD LED replacement. It was not a hard job and the result makes it very worth doing.Frankly, I have been avoiding SMD. This worked out very well and I am gaining more confident working with SMD - as long as I don't drop them. I KNOW I have at two SMD LED's somewhere in my work area, probably on the floor, waiting for an able archaeologist to rediscover them a few million years later.

author: funkyant
author_rank: Unknown
timestamp: February 13, 2015, 09:37:46 am
content: Haha. I love these forums O0