7-segment LED Display Diffuser Sheet

[Bluechip]

Having exhausted the possibilities with spiders, deceased or not, I will move on ... 

Somewhere, and I think it was on here, there was a post or two about the plastic covering for 7-seg. displays that improves the look of the things.

I have tried searches along the lines of the topic title but cannot find the stuff.

I don't really know what it's properly called.  I seem to remember it's a pale grey material.

IIRC there was a source and I think it was Amazon UK but I've had no joy.

Anyone know??

Dave.

[Don1966]

Is this what your looking for Dave?  https://www.amazon.com/Neewer-Correction-4-Color-Filter-Including/dp/B00W93FQNM/ref=br_lf_m_dnugov8gwxsuo4c_img?_encoding=UTF8&s=photo


Don

[Bluechip]

Hi Don

Thanks for the reply     Nope, not that suff. Found Gel filters on EBAY UK.

But .... having had another beer my little brain discovered the word Translucent and I think ( ?? ) it may well be this :

https://www.ebay.co.uk/itm/Acrylic-Perspex-Sheet-Genuine-Transparent-See-Through-Coloured-Cast-Sheets-A4/200998740120?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Dd8ef2b11751748269f06882be894cc46%26pid%3D100033%26rk%3D1%26rkt%3D8%26mehot%3Dpp%26sd%3D361132690564%26itm%3D200998740120&_trksid=p2045573.c100033.m2042

Link not too good, one of the options is 'Neutral Grey'

I hope it's the right stuff. I think it is. Sounds familiar.

Regards

Dave

[Don1966]

Yeah pretty much the same but thicker. They were all acrylic filters lens!

Don

[ddmckee54]

Bluechip:

What do you mean by "improves the look"?

What are you trying to do, hide the body of the display itself so that the chunky parts can't be seen?  Or do you mean to actually change the look of the displayed 7 segments somehow?

Don

[Bluechip]

Bluechip:

What do you mean by "improves the look"?

What are you trying to do, hide the body of the display itself so that the chunky parts can't be seen?  Or do you mean to actually change the look of the displayed 7 segments somehow?

Don

Hi Don

If you look at the pic. , you can see the 3  un-driven segments ( white )

With the diffuser (?) sheet they almost disappear.

Yes, the individual parts do tend to disappear also.

Don't know why the leftmost 2 appear brighter. They aren't. Maybe some artefact of the camera ... 

Dave

[Admiral_dk]

The LED's are multiplexed - meaning only on are actually lit at a time ….
So here you have a camera shutter time that probably equals six digits - like all four lit once first and the two leftmost once again.

[Bluechip]

Alas, no ... not mpxed   

Just connected to a DC PSU set at 4.2V ( 2 led's in series each segment ).


Dave

[Don1966]

Dave you have the LEDS connected to a power supply without a ballast resistor? If you do you will burn them out they are actually voltage regulators and have to have a ballast resistor in series with them. Like admiral said Display LED are usually muxed by a driver circuit unless you are building the circuit. A red diffuser would enhance the display and hide the components.


Don

[Bluechip]

Don

I am building the circuit ...    Just to remind myself how much I dislike wire-wrap.   Didn't mind it much at work with an electric wrap gun and pre-stripped wire ... this hand wrapping and stripping is a bit of a chore too far    Have now done a variant PCB with no wraps but a lot more links.  Some you don't win, some you lose .... 

You don't need limiter resistors if you set V _supply the same as the LED V _fwd, the current will the be very near to the nominal.

If you count up that piccy, there are 16 segments being driven.

The PSU output current draw is a shade over 170mA

ie. just over 10mA through each segment. Which is more or less what the data sheet says. 

If I drop the output to 3.2V they extinguish.  1.6V is not enough to drive the LED ( each of the 2 per segment)

No need to believe me .... try it for yourself .. 

Dave

Here you are, hang the expense ....  snip from data sheet

Disregarding the decimal point, it says ( V_f ) ... Somewhere between 4V and 5V the current will be 20mA through each segment. I'm at 4.2V and about 11-ish mA.  Well within the operating area.

[Don1966]

I understand what your doing and yes as long as you don’t over voltage them the resistor is not an option but a small value resistor would protect them. I did wire wrapping years ago very tedious work so good luck.


Don

[bent]

The two brighter ones are likely drawing a bit more current, due to a slightly lower Vf than the others...another reason to use ballast resistors to better distribute/regulate the loads, even if they are only a few or few 10's of ohms each.

[Bluechip]

They only look brighter in the pic.

To my eyes the 4 displays are the same intensity.   

Dave

[Bluechip]

Not that anyone is interested ....   except me ... 

Delivered today. This is the item. Transparent Black # 923  Works perfectly ... 

https://www.ebay.co.uk/itm/3mm-Colour-Perspex-Acrylic-Sheet-Plastic-Panel-55-DIFFERENT-COLOURS-A5-A4-A3/112387978610?ssPageName=STRK%3AMEBIDX%3AIT&var=412793456911&_trksid=p2057872.m2749.l2649

Dave

[GailinNM]

Dave,
Have not posted, but I have been following and and still interested.
My situation is different as I have AMD and it has taken most of my central vision and color vision.  I use different color filters and screen magnifiers to help me read the computer.  Seems that each site is different so have color filters at hand to try to improve contrast. Every bit of information helps.
Gail in NM