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