0

NeoPixel Sheet Part number 1558 design
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 3:22 pm

I recently perched the NeoPixel Sheet Part number 1558. I have a question regarding the design. I was wondering why there are 3 resistors on the board along with each LED? Do you have a schematic you can share with us that would explain in detail why these resistors are needed?
Thank You for your time.
Walter
IMG_0465.JPG
photo pointing out resistors
IMG_0465.JPG (381.02 KiB) Viewed 243 times

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by adafruit_support_bill on Sun Mar 19, 2017 3:34 pm

Full CAD files and a PNG of the schematic can be found here: https://github.com/adafruit/Adafruit_Br ... oPixel_PCB

adafruit_support_bill
 
Posts: 59590
Joined: Sat Feb 07, 2009 10:11 am

Re: NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 4:32 pm

Thanks for the reply Bill but..
The links on that page while have extensions .sch and .brd when you click on the links only code is displayed. no schematic or and explanation of design of the product.

please advise

Thank You
Walter

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by franklin97355 on Sun Mar 19, 2017 4:45 pm

Those are Eagle CAD files. You can get Eagle here.

franklin97355
 
Posts: 15885
Joined: Mon Apr 21, 2008 2:33 pm
Location: Lacomb, OR.

Re: NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 6:57 pm

I am unable to install any software. Any chance you have a drawing in common .pdf format? of can yo just explain in detail why these resistors are needed?

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by adafruit_support_bill on Sun Mar 19, 2017 7:27 pm

Here is the png of the schematic:
Attachments
Pixel Schematic.png
Pixel Schematic.png (4.55 KiB) Viewed 217 times

adafruit_support_bill
 
Posts: 59590
Joined: Sat Feb 07, 2009 10:11 am

Re: NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 7:57 pm

Thank you so much. Now I have to ask why do you put resistors inline with the data lines on this product and not on say your neopixel rings for example? and what is the reason for the 1k ohm. The semantic does not show any pin number of the LED so I mite be confused.

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by franklin97355 on Sun Mar 19, 2017 8:05 pm

Here is the datasheet for the ws2811 chip in that pixel. https://cdn-shop.adafruit.com/datasheets/WS2811.pdf

franklin97355
 
Posts: 15885
Joined: Mon Apr 21, 2008 2:33 pm
Location: Lacomb, OR.

Re: NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 8:14 pm

Do you have the data sheet for the LED w/that chip inside?

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by franklin97355 on Sun Mar 19, 2017 8:21 pm

What is it you are looking for? The coding is the same. We have the ws2812 pixel datasheet.

franklin97355
 
Posts: 15885
Joined: Mon Apr 21, 2008 2:33 pm
Location: Lacomb, OR.

Re: NeoPixel Sheet Part number 1558 design

by walterpolan on Sun Mar 19, 2017 8:28 pm

The size/spacing of the pads, the pad numbers and names of the LED.
AKA LED Datasheet link you sent.

Interesting the LED data sheet does not show any resistors on the data line as in the IC data sheet.

walterpolan
 
Posts: 6
Joined: Sun Mar 19, 2017 12:18 am

Re: NeoPixel Sheet Part number 1558 design

by adafruit_support_bill on Mon Mar 20, 2017 5:59 am

The resistors on the data lines help suppress ringing on longer runs. Since we have no control over the distance between pixels with the breadboard version, we add them to both inputs and outputs.
https://learn.adafruit.com/adafruit-neo ... -practices

adafruit_support_bill
 
Posts: 59590
Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.