I'm a web developer / system admin and I have a client project with a project that is just beyond me. In a nutshell, we need to the following capabilities:

  • Track the status of hundreds of Passive Infrared Sensors
  • Track the status of hundreds of lights (not sure yet whether it will be a simple BOOL value or a percentage / brightness value)
  • Trigger any of the lights individually or in groups from a main console and eventually from mobile apps
  • Log all of the state changes for the motion sensors and lights
  • Generate reports and pattern analysis based off the logs

The programming involved will be cake. I understand how that works.. but where do I even start in controlling lights and tracking that many streams of external input? What hardware and software should I be looking at? Can I build this on top of a linux server for easier access from a mobile device?

  • \$\begingroup\$ How often will you be querying these lights and sensors? (ie 100 times per second? slower? faster?). \$\endgroup\$
    – Jon L
    Jun 6 '11 at 15:47
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    \$\begingroup\$ It sounds like you need some sort of data concentrator that then communicates to your computer in a way the computer can understand. I'm sure you don't want to run ethernet cables to every sensor and light, so you need some simpler hardware to communicate with all those endpoints, then have it be the single point of contact to your main computer system. That could be via USB or ethernet, for example. To make a solid recommendation I need to know more about what the interface to these sensors and lights look like, if there is any currently at all, the physical distance, etc. \$\endgroup\$ Jun 6 '11 at 16:04
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    \$\begingroup\$ You mention the brightness value of the lights. Does this mean we're talking dimmers? Hundreds of them? \$\endgroup\$
    – stevenvh
    Jun 6 '11 at 16:07

There are several companies who provide turn-key solutions for this kind of application when it's wireless and internet connected. Some, from hardware to web APIs.




They may be a good place to start.


I think you'll want to look into DMX and RDM. Those are more output protocols for lighting and theatre systems. With RDM, one could do sensors.... but. I never used it, but perhaps Open Sound System would work.


Maybe using 1-wire technology might be of some use


I have worked on projects were i gathered data from several thermometers just from running a 2 core cable +5v and -5volt and the data was sent passivly to and back of the micro controller.


I have not seen a 1-wire light sensor - but a temp-ic could pick up heat emmited from lights to knwo if they are on or not?

You will need a 1-wire standalone switch to drive hundreds of ic's and an interface like arduino to gather data and send it to serial so it can be decoded.

  • \$\begingroup\$ @ppumpkin - Please don't add a signature ('T') to your posts. Your signature is displayed at the bottom right: it links to your profile and even features a glowing pumpkin! \$\endgroup\$ Jun 7 '11 at 21:09
  • \$\begingroup\$ @Kevin Sorry- that was not a signature - just did not delete the whole sentence I wanted to write. Apologies. Will keep it cleaner. \$\endgroup\$
    – Piotr Kula
    Jun 8 '11 at 8:07

Is there any reason you're looking to develop a custom solution rather than looking at existing commercial solutions to this problem? There are many, many existing solutions in this space which vary widely in cost, complexity, and capability. The more popular solutions for home and smaller installations include Z-Wave, Insteon, and ZigBee; (ZigBee is the system that I am most familiar with). There are other solutions available for larger commercial installations.

As with most questions of this nature, a useful answer will depend upon your actual requirements. Are the PIR sensors already in place? Does the customer already have an automation/lighting solution in place?


I have implemented a system just like this for a client.

In their case, they were a film studio making a CGI film and each worker needed to be able to dim their lights to their needs as well as allow for emergency situations.

I used a commercial solution which used RS485 for control, DALI for the lights and microcontrollers for the logic, there was also a dry-contact from the alarm to bring everything to full-brightness in an emergency.

The individual control was mine running from a webserver with a RS485 port.

By sitting on top of a commercial solution, you hand off the worry of providing something that needs to run reliably 24*7*365 and get to focus on the interface.


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