light counter/detector

[jms1989]

So I want make a light detector/counter. One that counts how many times the light in the room was turned on and for how long. To stick in the bathroom and do a little math to see how much energy is being used. Even better, it could detect for humans to help figure how many hours the light is being left on unattended. Maybe unnecessary but I'm curious. how much energy is being wasted due to people who can't seem to remember to turn off the light when they leave the room.

I'm thinking I'd use an ardunio to do the work and be powered from a 9v battery thru a 5v reg. To save the log, I'd ether need to use a sd card or send it wirelessly to a always on pc. I already have a arduino and a sd card interface to attach to. I can find a photo resistor anywhere but idk how to detect for people. how would y'all suggest for the wireing and code? I have no idea how to code this.

Thanks

 

[wp100]

Hi,

Your idea should work though I would stick with the SD card rather than the wireless option which can be more problematic.

If you look in the Arduino Playground and forum you will find many ready made modules for things like sd cards and photo detector that will help you get going.
However you will probably have to program up your own code for adding up the On times and energy use etc.

Again there are many tutorial around for the Arduino, like anything you really need to start with the Hello World / Flashing led.
Heres one good tutorial if you can stand Jeremy; its sponsored by Farnells / Newark
https://www.youtube.com/playlist?list=PLA567CE235D39FA84

 

[BradtheRad]

To detect a light on will be easy to do.

To detect people will be a challenge. They could be moving, or they could be stationary, for unknown periods.

Hence it could require a combination of detectors:

infrared
motion
sound
light
etc.