Light Geekery

Arduino, Automation, Lights

After building my sketchy micro-controller based AC light dimmer, I noticed that while fading though the dimming levels, it wasn’t a linear response. There was a noticeable “stall” in the fading around the mid-range of values. So to fix this, and waste a perfectly good Thursday night, I had the micro-controller watch the response of the light with a photo-resister and see what the problem was.

IMG_2967.jpg

Keeping and eye on the light

The resulting response was nowhere near even. So I plotted the values and its derivative.

LightResponse
LightResponseDerivative

So to adjust the problem, I altered the distribution of the fade values. By decreasing the density of points around the “delay”, which was around 9000 on a scale of 0 to 16000, I was able to smooth out the fade.

distribution


Resulting distribution


The result is a seemingly linear light fade-in and fade-out.

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