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- --
- -- Light sensor on adc0(A0), RGB LED connected to gpio12(D6) Green, gpio13(D7) Blue & gpio15(D8) Red.
- -- This works out of the box on the typical ESP8266 evaluation boards with Battery Holder
- --
- -- It uses the input from the sensor to drive a "rainbow" effect on the RGB LED
- -- Includes a very "pseudoSin" function
- --
- -- Required C Modules: adc, tmr, pwm
- local redLed, greenLed, blueLed = 8, 6, 7
- local function setRGB(r,g,b)
- pwm.setduty(redLed, r)
- pwm.setduty(greenLed, g)
- pwm.setduty(blueLed, b)
- end
- -- this is perhaps the lightest weight sin function in existence
- -- Given an integer from 0..128, 0..512 approximating 256 + 256 * sin(idx*Pi/256)
- -- This is first order square approximation of sin, it's accurate around 0 and any multiple of 128 (Pi/2),
- -- 92% accurate at 64 (Pi/4).
- local function pseudoSin(idx)
- idx = idx % 128
- local lookUp = 32 - idx % 64
- local val = 256 - (lookUp * lookUp) / 4
- if (idx > 64) then
- val = - val;
- end
- return 256+val
- end
- do
- pwm.setup(redLed, 500, 512)
- pwm.setup(greenLed,500, 512)
- pwm.setup(blueLed, 500, 512)
- pwm.start(redLed)
- pwm.start(greenLed)
- pwm.start(blueLed)
- tmr.create():alarm(20, tmr.ALARM_AUTO, function()
- local idx = 3 * adc.read(0) / 2
- local r = pseudoSin(idx)
- local g = pseudoSin(idx + 43) -- ~1/3rd of 128
- local b = pseudoSin(idx + 85) -- ~2/3rd of 128
- setRGB(r,g,b)
- end)
- end
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