Network Light Dimmer


This project is one of many I have undertaken to control my house using a set of rules, a web interface, a logger and many more components. This project is a light dimmer which has multiple control interfaces such an RS485 network, an infrared remote control, a proximity touch slider or touch sensor.
    It is based on a ATMega8 and the well known Qprox QT401/QT110proximity sensor. The Mega8 had lots of things to do: detect zero crossing of phase, calculate the firing angle for the triac, manage the network communications, check for a finger presence and position on the proximity touch slider and detect and decode infrared coming from a remote control. The device is powered from the RS485 network connection which has +12, data+, data- and GND.  On the schematic you will see that there are two detectors, one is the slider, and the other is a simple touch detector.  It was done like this so that non-dimmable loads can be driven by using the touch detector as the control. That is why there are circuit pads on the board for two sensors.


  • Slider QProx sensor
  • IR receiver
  • RS485 interface
  • Opto isolated
  • Up to 500watts
  • Network firmware upgradeable



Dimmer Schematic

Slider Schematic

Source Code

9 Comments to “Network Light Dimmer”

  • Ben November 15, 2010 at 7:24 pm

    It seems a lot of us like to experiment with dimmers ;-P
    I see you solved the power source by using the RS485 as a source,
    Im trying to develop a nice AC-DC power supply with a Viper12A I want it to be small and flexible, have you ever worked with such designs ? (ie. transformerless psu)

  • admin November 15, 2010 at 7:47 pm

    No I had never work with that,


  • Mike May 30, 2011 at 3:01 am

    Cool idea, I am working on a similar project.
    What are you using to step down from mains? I don't see a transformer in the pictures. 
    I see a regulator for Vcc, which regulator are you using to provide +12?

  • admin May 30, 2011 at 1:07 pm

    My RS485 cable bring the 12Volts


  • miguel ANgel December 13, 2011 at 4:32 pm

    PBC may thereby please give me a great project

  • Chris January 15, 2012 at 4:43 pm

    Very nice project. Is the PC364 being used for zero cross detection? Is there a more detailed description avaliable for the source and how to connect up a load? What are the CON and HEADER pinouts and what are they used for? (Think i have them figured out, but want to be sure)
    Thanks, great work!

  • admin January 16, 2012 at 3:31 am


    Yes the PC364 is for zero detection. I don’t have more documentation on this project

    Sylvain Bissonnette

  • Karsten February 15, 2012 at 10:35 am

    Hi Sylvain
    Could you email schematics? (easier so I don't have to recreate).
    Did you consider noise suppression, adding a capacitor and a coil?
    Have you tested with dimmable low power lamps (not all dimmers work with these for some reason)?

  • admin February 15, 2012 at 2:00 pm

    I don’t give more that what is on my web site, I had test with 7w light without problem, for the noise suppresion there is no place in the box for that

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Please note

All my source codes were taken from my personal projects.

Everything is for your information only. The C/C++ codes have been written
with ICCAVR. You can find the header and source CRT files by downloading their compiler.

All is for your information and everything is AS IS without any warranty of any kind. No other files are available and I don't make any modification for any body.



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