What is DMX LED dimmer?

It would be a bit boring if your analog LED strips shine in just one color. All the more if you couldn’t control the intensity of light. In our previous blog, we explained how you can control and power your strips. Using DMX protocol, we can connect our lights to yet another device called DMX LED Dimmer.

Representation of DMX channels as collumns with three collumns circled as channels LED dmx dimmer can receive and convert.
Three of 512 DMX channells that LED DMX dimmer receives and convert into three basic colors.

Color intensity and flickering

DMX LED dimmer achieve different levels of light intensity emitted by LED strips by constant flickering. In essence, the device regulates power supply in the perspective of voltage. 100 percent voltage equals maximum intensity. Minimum is zero voltage and our strip is basically cut off of power supply. The recurrence between the two states is so rapid that the human eye cannot actually perceive it. If, however, you shoot a video of a LED light which uses dimmer with low frequency, you can observe this phenomenon on camera. Dimmers we use in our installations all work in very high frequencies for the very same reason.

LED DMX dimmer used in car headlight with low frequency
LED headlight flickers due to low frequency

Pulse Width Modulation

In some cases, especially when building a TV studio or large installations, we use thousands of single LED pixels. Although LED strips consume very little electricity, the sheer size and number of lights used would amass for a pretty high electricity bill. So, in order to decrease the power consumption and extend the lifecycle of LED strips, dimmers use power supply control technique called Pulse Width Modulation, or PWM.

For example, if the dimmer’s PWM is 2 kHz, the dimmer turns on and off the supply 2000 times per second. Intensity of the light is the ratio between on and off time. A hundred percent “ON time” equals to 100% brightness of the strip.

Oscilloscope showing power supply to LED in regards to its brightness
On oscilloscope we can see ON/OFF duty cycle for apx. 50% brightness.

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