Energy-saving project involving sensor

[SalfordPhysics]

I have come up with a new idea for an energy saving project for my course (which has a novel element - they're not expected actual ideas to take off)

Having thought a few things over, I am now thinking of simply saving energy in office's, particularly where offices are divided up into sub-offices, each with their own lighting etc.

I wish to install a sensor on top of a computer monitor (or somewhere approximately thereabouts), and a receiving 'pad' on the back of a chair (the side you sit against so the pad and sensor are facing).
When a person sits on the chair i.e.; when the pad is blocked, the lights turn on.
When the chair is empty i.e.; when the pad is exposed, a timer is started.
After 30 seconds, the lights will start to dim.
After another 30 seconds (thats 1:00 from initially beginning the timer), the lights will be at their dimmest point.
I will also be proposing to use LED lighting to for their high efficiency, long lifetime and low cost.

I am particularly concerned about what combination for the sensor and the pad to use, since I want humans to effectively block this connection.
All help is greatly appreciated.

 

[berkeman]

I have come up with a new idea for an energy saving project for my course (which has a novel element - they're not expected actual ideas to take off)

Having thought a few things over, I am now thinking of simply saving energy in office's, particularly where offices are divided up into sub-offices, each with their own lighting etc.

I wish to install a sensor on top of a computer monitor (or somewhere approximately thereabouts), and a receiving 'pad' on the back of a chair (the side you sit against so the pad and sensor are facing).
When a person sits on the chair i.e.; when the pad is blocked, the lights turn on.
When the chair is empty i.e.; when the pad is exposed, a timer is started.
After 30 seconds, the lights will start to dim.
After another 30 seconds (thats 1:00 from initially beginning the timer), the lights will be at their dimmest point.
I will also be proposing to use LED lighting to for their high efficiency, long lifetime and low cost.

I am particularly concerned about what combination for the sensor and the pad to use, since I want humans to effectively block this connection.
All help is greatly appreciated.

Many office PCs/Monitors now have a video camera on them for teleconferencing. You could process that image to figure out if a person is sitting in the chair, or detect the pad that you mention.

 

[SalfordPhysics]

Many office PCs/Monitors now have a video camera on them for teleconferencing. You could process that image to figure out if a person is sitting in the chair, or detect the pad that you mention.

Thank you for this advice Berkeman, this has really given me a huge breakthrough.
If I were to stick with the idea of the pad, would I be better of sticking to a specific material or is the material of the pad arbitrary? I wonder this as to reduce any possible failure's in detection.

 

[berkeman]

Thank you for this advice Berkeman, this has really given me a huge breakthrough.
If I were to stick with the idea of the pad, would I be better of sticking to a specific material or is the material of the pad arbitrary? I wonder this as to reduce any possible failure's in detection.

This pad would need to be attractive enough so as to not bother the person who uses the chair on a daily basis. It would need to be soft enough so that when the user leans back, it is not uncomfortable for them in any way. It should have some pattern on it that makes it easy to recognize by your sensor/camera -- maybe some kind of stylized logo for your company that is attractive and also has a definite pattern as part of it.

BTW, how are you going to know to turn on the lights when a user enters a dark room or cubicle? If you use a camera to look for the pad/logo, but it's dark in the office, nothing will tell you when the user sits down and blocks the pad...

I do have one idea for solving that, but will let you think about it some to come up with your solution(s).