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1.2" 7-segment LED is too bright!
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

1.2" 7-segment LED is too bright!

by 2bhandyguy on Wed Feb 13, 2019 2:33 pm

Hi all,
Even on the lowest brightness setting, this display is too bright!
The pins are:
"D" - I2C Data Pin (SDA)
"C" - I2C Clock Pin (SCL)
"+" - 5v. (Will not run on 3.3v!)
"-" - GND
"IO" - I2C bus voltage.
I am wondering if I could insert a resistor on the +5v pin to dim it?
If so, suggested resistor values?
(This is part# 1268 - LED with I2C backpack)

Thanks!

2bhandyguy
 
Posts: 20
Joined: Sat Nov 04, 2017 1:54 am

Re: 1.2" 7-segment LED is too bright!

by adafruit_support_bill on Thu Feb 14, 2019 6:52 am

A resistor is not likely to work well. At best, the voltage drop will vary with the number of segments lit. At worst, it may drop low enough to cause the backpack to malfunction.

Another option for reducing intensity is to put the display behind a piece of grey or bronze smoked acrylic: https://www.usplastic.com/catalog/item. ... emid=34610

adafruit_support_bill
 
Posts: 72720
Joined: Sat Feb 07, 2009 10:11 am

Re: 1.2" 7-segment LED is too bright!

by 2bhandyguy on Thu Feb 14, 2019 1:15 pm

Thanks for the suggestion, great minds think alike!
20180607_130422_HDR.jpg
20180607_130422_HDR.jpg (894.73 KiB) Viewed 62 times

I already have the LED behind the darkest smoke acrylic available. It's still too bright at night!
My other option is to dismantle and insert a Lee gel filter behind the acrylic; that will be tough as the acrylic is essentially glued to the cabinet it's in.

So not likely, but possible? It's cheap and easy enough to try...

2bhandyguy
 
Posts: 20
Joined: Sat Nov 04, 2017 1:54 am

Re: 1.2" 7-segment LED is too bright!

by adafruit_support_bill on Thu Feb 14, 2019 1:32 pm

Nice looking clock! I really like the flush buttons on the top.

If you are adding filters, you can also take advantage of the narrow spectrum emitted by the LEDs. A red or amber filter will sharply attenuate the green part of the spectrum. I suspect a strip of wide Kapton tape (amber color) applied to the face of the display module would do the job.

adafruit_support_bill
 
Posts: 72720
Joined: Sat Feb 07, 2009 10:11 am

Re: 1.2" 7-segment LED is too bright!

by 2bhandyguy on Thu Feb 14, 2019 2:21 pm

Thanks, the buttons were a lot of work, but worth the effort! Whatever filter I use, I have to remove the front plate, which will be messy and possibly destructive.

2bhandyguy
 
Posts: 20
Joined: Sat Nov 04, 2017 1:54 am

Please be positive and constructive with your questions and comments.