I am completely new to Arduino and programming in general so please forgive my ignorance and incorrect terminology.
I have a basic understanding of how the inputs and outputs work, but I would like some information on the sensors to use and how accurate they are. What I want to do is build a puzzle box that can only be opened in a specific room at a specific height (elevation). There will also be a couple of 'knock' and light sensors, but these are straight forward enough.
So, questions:
Is the room specific opening possible? From what I have read GPS is not accurate enough. Anything else that might work?
Elevation, how accurate are these sensors? and how do they work? I have a 2 story house will that make a difference?
Sounds fairly challenging. I suggest you keep the idea in the back of your mind and, If you are serious, start at the beginning and learn. Ever hear this...?
"He who would learn to fly one day must first learn to stand and walk and run and climb and dance; one cannot fly into flying."
GPS indoors would be a problem, WiFi location is not yet available for a project like this but some other sensing could work.
You would need something in the room to generate a signal that the puzzlebox could detect like Ultrasonic, Infrared or maybe radio signal.
I think the simplest would be Infrared see: IR Communication
You may need several transmitters (could be as simple as remote controls with a button jammed down) so the Arduino can 'see' the IR from all angles.
Elevation, how accurate are these sensors? and how do they work? I have a 2 story house will that make a difference?
There are very accurate Pressure/Altitude sensors which could certainly distinguish one floor of a building from the next, but because they operate on pressure it might be difficult to get more accurate operation indoors.
In any case, the reading would have to be calibrated before use because the barometric pressure changes with the weather. Indoors you get relatively large changes in pressure from air conditioning and doors opening and closing.
If you wanted a specific height in a specific room, it would not be impossible (but a bit tricky) to use Infrared for this as well - you could 'beam' out an IR signal thru a slot so it should only be seen at the given height, although reflections may cause a bit of a problem.
Yours,
TonyWilk
P.S. Can't dance that well, but I can fly a Gyroplane
You would indeed need some form of active system in the house that tells the box it's in the correct room. IR would be suitable as it's blocked by walls. A bluetooth transmitter may work, as those have limited range (around 10 meters - less through walls) so the box may open only when that transmitter is in range and can be connected to.
Atmospheric pressure sensors can easily tell two stories apart but you'd have to recalibrate every few hours - and much more often if e.g. a typhoon is approaching or a front is passing.
