Need help if my project is possible and how

Hi Arduino community

I am about to start a project with the Arduino, but i don´t really know for sure what components I would need.

The project is that there would need to be a Arduino uno rev3 on the table connected to a constant power source. USB or AC/DC. It should via a PIR Sensor or a temperature sensor (maybe mlx90614) or a third thing, be able to detect when a human has his legs under the table (sitting down). Then after an hour turn on a LED light which remind the person to stand up.
The area of detection need to be kinda wide to make sure that it is spotting the person regardless of the way he is sitting, it also need to be able to detect him even tho he isn't moving his legs.
Thanks for any suggestions and help in advance.

The UNO and PIR sensor should do it - lots of 7.5vdc plug in power supplies with a plug that goes into the UNO

I might use 10mm defused bulbs - larger and easier to see - but might be over kill - also maybe 2 or 3 bulbs - but please use defused bulbs - noticeable but not as annoying as a clear focused lens

The programming should be fairly straightforward - look at the "do several things at once" at the top of the forum on how to do a delay without a "delay" statement - a delay statement stops the processor on that statement until it times out

Think about a push button to set the time back maybe 5 minutes or so - if someone is on a phone call they might want to delay things and not have the lights flashing at them

PIR Sensor is not able to detect human if he is not moving his legs. But you can still use this by using a timeout for movement. I think, a people can not keep the leg unmoving in long time when sitting. For timeout and timer for warning, you can use millis() function instead of delay(ms) , see How to use millis() instead of delay()

It's also hard to control the range and sensitivity of a PIR. So it might "see" the legs of people walking around the room. What about a pressure switch in the chair?

aarg:
It's also hard to control the range and sensitivity of a PIR. So it might "see" the legs of people walking around the room. What about a pressure switch in the chair?

Then I would need at way to transfer the data wirelessly from the pressure switch to the Arduino on the table. So think that PIR sensor would work best

IoT_hobbyist:
PIR Sensor is not able to detect human if he is not moving his legs. But you can still use this by using a timeout for movement. I think, a people can not keep the leg unmoving in long time when sitting. For timeout and timer for warning, you can use millis() function instead of delay(ms) , see [How to use millis() instead of delay()](http://How to use millis() instead of delay())

I seem to not be available to open the link, but how would this delay thing work, would it be available to detect when the human is leaving the work place. fx if there isn't movement in 7-10 minutes or what?

saildude:
The UNO and PIR sensor should do it - lots of 7.5vdc plug in power supplies with a plug that goes into the UNO

I might use 10mm defused bulbs - larger and easier to see - but might be over kill - also maybe 2 or 3 bulbs - but please use defused bulbs - noticeable but not as annoying as a clear focused lens

The programming should be fairly straightforward - look at the "do several things at once" at the top of the forum on how to do a delay without a "delay" statement - a delay statement stops the processor on that statement until it times out

Think about a push button to set the time back maybe 5 minutes or so - if someone is on a phone call they might want to delay things and not have the lights flashing at them

What if the person leaves the work place, it would need to detect the human being there for an hour. Of course it should not reset if the human is only away for 3 minutes, but yeah. Think that the heat sensor would work better, because It can detect the heat from the person. And feel if there isn't a person there anymore.

@mikkell

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mikkell:
I seem to not be available to open the link, but how would this delay thing work, would it be available to detect when the human is leaving the work place. fx if there isn't movement in 7-10 minutes or what?

I updated the link How to use millis() instead of delay(). Detecting human leaving office can be done by using a timeout.