Saturday, July 30, 2016

AC PWM Dimmer with Light Sensor


You can see this article as a continuation of the previous BH1750FVI - I2C Light Sensor Driver one.

    The main goal of the project is to create a AC Mains Light dimmer that can automatically control the level of light and keep in in the desired set interval without any external intervention.

   Why would you be intrested in such a setup? Well, if you have any interest in hydroponics, photography, or anywhere where you need some sort of constant flood light lamps with precise light intensitity level setup then might be a good idea to take a look :)

What we will need:


     Connection with the ESP8266 nEXT EVO Board is very easy, as MPU6050 GY-521 Module connector is fully compatible with the nEXT Bus connector. Depending on how to you choose you socket type, you can install it on TOP or Bottom of the ESP8266 nEXT EVO Board :

BH1750FVI Module directly connected to the ESP8266 nEXT EVO Board

And the whole project setup, with MPDVv4 AC Dimmer connected on ESP8266 GPIO13 (pin 7):

MPDM v4 + nEXT EVO + BH1750FVI

Closer look, MPDMv4 connected at ESP8266 GPIO13 (Pin7) for PWM control

Software implementation

You will need also the code from the previous BH1750FVI article. Please take also a look there for more details.

1. Ligth level auto-adjust function

 function set_light()
    ll = light - hst    --lower level
    lh = light + hst    --upper level
    if (lux < ll) then
       i = i - step
       if (i<0) then i = 0
       pwm.setduty(7, i)    
    if (lux >lh) then
       i = i + step
       if (i>880) then i = 880
       pwm.setduty(7, i)    
    --print("Auto Level Adjust : "..i)
    if (ll< lux and lux < lh) then
      if (p<1) then p=1
      if (p<2) then
         print(string.format("\nLight Level: %0.2f lux",lux))
         print("Auto Level Adjust : "..i)

Main Program
--PWM testing for MPDMv4 AC Dimmer Board

pwm.setup(7, 500, 850)    --MPDMv4 control pin
i=10                                  --initial Light Level

pwm.setduty(7, i)             --set initial ligfht level

light = 250                       --light level
hst = 40                            --histeresis coef for desired light interval
step = 1                            --light step

--read light intensity value every 50 and autoadjust Light Dimmer Driver accordingly
tmr.alarm( 1, 50, 1, function()

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