Sigma-delta or Led Channel (PWM)? Which is better?

[JoaoLopesF]

I'm working on a project. This have 8 channels (Sigma-Delta ou LedC) of ESP32 connected to leds.

Frequencies of blink can vary from 0.2 to 50 Hz (ussually 0.5 to 20 Hz).

I did work with both types (by #define):

- With sigma-delta
- With Led channel

Technically sigma-delta is better than PWM (LedC), is this correct?

Questions from a beginner in sigma-delta?
- Is the capacitor needed to plug leds ?

f you add a capacitor between the output pin and ground, the average output voltage will be Vdc = VDDIO / 256 * duty + VDDIO/2, where VDDIO is the power supply voltage.

- Why the range recommended is:

recommended range is -90 ~ 90

seen in http://esp-idf.readthedocs.io/en/latest ... delta.html

[Archibald]

As far as I'm aware, LEDC can flash an LED only down to 1 Hz.

It sounds like you need to drive the outputs directly from code especially if you wish to drive the 8 outputs in a sequence.

Beware of photosensitive epilepsy (link).

Regarding . . . .

If you add a capacitor between the output pin and ground, the average output voltage will be Vdc = VDDIO / 256 * duty + VDDIO/2, where VDDIO is the power supply voltage.

. . . . in my view it is inadvisable to connect a capacitor between output pin and ground without a series resistor.

[JoaoLopesF]

Archibald,

Beware of photosensitive epilepsy (link).

I knew this, your advice is true for avoid problems with epileptics

in my view it is inadvisable to connect a capacitor between output pin and ground without a series resistor

This is true to me too

Thanks for your response

[Deouss]

Or use Remote Control feature.
It has 8 channels exactly as you need and allows smaller frequencies too
I think that would be perfect solution here

[JoaoLopesF]

Hi, Deouss, tanks for response

Or use Remote Control feature.
It has 8 channels exactly as you need and allows smaller frequencies too
I think that would be perfect solution here

How use Remote Control feature (RMT) to control brightness of leds ?

[Deouss]

Look at the rmt example included with esp-idf. All you need is to set up the transmission channel and control the transmitted waveform that you amplify to your leds.

[JoaoLopesF]

Hi Deouss , I do this, thanks a lot

I see that top Arduino libraries for Leds, as FastLed, using RMT in Esp32, why not Sigma or Led Channel ?