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Topic: Arduino WS2812B Data Pin Resistor (Read 298 times) previous topic - next topic

Linsane

I want to connect my Arduino to a WS2812B LED Stripe. My Setup is currently working totally fine with a 1000 Ohm Resistor between Pin 13 on my Arduino and the DataIn of the Stripe. Now some sites say, that I should use 470 Ohm, others say something between 100 and 500, others say I should use none.

Could someone please explain to me what is actually the best way and why it is the best way.

PieterP

That resistor is for impedance matching between the Arduino's low-impedance output and the WS2812B's high-impedance input. When using long wires, they act like transmission lines, causing reflections, resulting in unwanted oscillations, ringing and noise.

The datasheet doesn't specifically say anything about it.

If the resistance is too low, it doesn't have much effect, and if it's too high, you lose the sharp edges, causing signal degradation as well.
Most sites seem to recommend 330-470 ohms, so 1000 Ohms might be a bit high.

Pieter

Grumpy_Mike

#2
Jun 23, 2018, 11:47 pm Last Edit: Jun 23, 2018, 11:48 pm by Grumpy_Mike
Quote
When using long wires, they act like transmission lines, causing reflections, resulting in unwanted oscillations, ringing and noise.
As is illustrated by these oscilloscope traces I took.

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