We want to make box that would be insert in a granit tile floor. The dimesion will be 44" long by 15" wide and 3 or 4 inches deep. The casing will be in stainless steel all sealded with a 3/4" thick frosted glass. under that we will lay the intercative panel.

Can we put the panel at 3 inches from the surface will they detect when peoples walk over thems.

And i also want to know if it could be possible to change the type of sensor for proximity sensor. Cause we would like to use the panel upsde down under chair when the people sit on the chair it will lit under the chair or when they passes their hands over the chair.

Everything will be outdoor in montreal so there is winter and summer time so hot and cold what is the operating temperature for the panels.

The panels should work fine three inches below the surface, but you may want to increase the sensitivity of the panels due to the thickness of the glass. If you're starting with a kit, that should be feasible.

When you say you want to change the type of sensor, do you really mean a different kind of sensor, or do you mean you would like to mount the sensors either away from the board or on the back side of the board? It should be relatively easy to wire them up off-board or on the back of the board if you're starting with a kit.

We haven't tested the panels in extreme temperatures. They are designed to work at room temperature and we have operated them at summer temperatures, but we haven't tried cold yet. We could probably stick one in the freezer for you to see how it fares. More importantly, you will want to ensure that the enclosure is not subject to condensation, as the boards are not tolerant of getting wet.

Tanks to answer rapidly, Yes try one in the freezer if you can but i will buy a kit assembled and one disassembled to test too.

I mean changing the sensor type so it could dectect behind a non transparent surface as granit.

The apparel would be place in a sealed environnement made of stainless steel for the chair surface and a temepred thermos windows under to let the lights goes true.

Or maybe we could put the panel inside a thermos windows.

Does it get hot i mean does it produce to much heat for that.

>I mean changing the sensor type so it could dectect behind a non transparent surface as granit.

That's a somewhat difficult task. You can find "touch" sensors that require a physical touch (by skin, usually), and various sorts of proximity sensors that work optically. Optical sensors (PIR, other infrared, visible light) all detect light... and if you use a fully opaque object (like a slab of granite) then no optical sensors can work. If you have a different suggestion, please say so. Also: LEDs are not visible behind a slab of granite, so you might take that under consideration as well.

>Does it get hot i mean does it produce to much heat for that.

How hot it gets will depend on how good the insulation is and the external environment. The most heat that can be produced is about 5 W, distributed over the full area of a panel. That's like a 5 W night light. Almost certainly, the amount of heat delivered by sunlight will greatly exceed this.

I mean capacitive sensors like these

http://www.lionprecision.com/tech-library/technotes/cap-0020-sensor-theory.html

And the panel will be mount upside down so the led point to ground under the seat between the granit seat and a thermal windows under.

But i will need to replace the IR sensor for this kind of sensor, i think it could work.

For the temperature i guess it will be okay to sealed the panel in thermal windows as it is protect from the direct sunlight by the granit slab and i could also put a small 12v fan in the casing.

Capacitive sensors like the ones that you described are the types that I was referring to when I said "touch" sensors.

>i could also put a small 12v fan in the casing.

If it's a sealed system, then a fan is only going to add heat to the system, not remove it.

The Lion sensor products appear to work with a range up to about 10 mm max, meaning that they wouldn't work through 1 cm of granite.

As an alternative to a different sensor technology, you might consider modifying your project a bit. There are some translucent stones that might work, or you could bore a 1 cm diameter hole through the granite and plug that with glass or something similar.

I have seen that using arduino as a capacitive sensor with a 40 M resistor the sensor will start to respond 12-24 inches away

As you could see on this page

http://www.arduino.cc/playground/Main/CapSense

The fan would be outside of the thermal glass but in the casing and ther will be vent hole to carry the heat outside.

I haven't said that it can't be done-- nor that it's easy. One thing to be aware of is that the capacitive system may behave very differently under different weather conditions including humidity.

Thanks to all for your advice,

I have ordered 2 interactive panel one already mounted and one not i will go ahead with that and i will keep you inform.