point A to point B

Other Hardware Sensors
1

hello,

i want to make something that can mesure ( at the cm or inch ) A point a to point B. But i can't use any ultrasonic sensor because there can be a wall between . I want to press a button on point A and walk over to B and then have the distance but the distance is between ( 20cm and 9m ).

thanks
( my english is bad , i know and sorry )

2

What is the Arduino's rôle in this?
What sort of displacement do you need to measure?
Do you you want to tell us what the constraints are?

3

hi
i just need to make something that mesures the distance in cm from a to b an witch sensor i need to use to make this

4

Tape measure.
Vernier.
Micrometer.

5

that is not going to works because it needs to be done rely quick and really compact so electronic is the only way to go

6

andreeke:
But i can't use any ultrasonic sensor because there can be a wall between . I want to press a button on point A and walk over to B and then have the distance

If there is a wall between the two points how are you going to walk from one to the other?

Steve

7

yes but it need to mesure the distance i've walked

8

Pedometer.
Theodolite.

9

Get a floor plan of the house, to scale. Carefully mark A and B on the plan, and measure the distance between them. Scale up the result according to the plan scale.

10

The modus operandi will be : the first push on a button is the point of zero a red light is lighting up and from the moment you are at 5 meters there is a green light lightning up. So the point zero is the middle of the circle.

The biggest problem is that the "thing" has to remember where point zero is.
I was think at a kind of gps with high precision.

Or maybe you guys are thinking of something else

THX a LOT

11

The biggest problem is that the "thing" has to remember where point zero is.

Not a problem. Just store the coordinates of the zero point in the thing's memory.

Then use the Pythagoras Theorem to compute distance from zero.

12

yes but i need i kind of module to have precise coordinates

13

"Precise coordinates" appears to be a bigger problem than simply storing the coordinates of the zero point, don't you think?

14

yes that was also a problem

15

The good thing is you don't care about your absolute place in the world, only about your location within the house.

I think the best option is to mimic GPS. Place a few (at least three) radio beacons in the home. Get a device that can triangulate it's location to those three beacons. As long as you don't move those beacons you can accurately locate yourself within the house, relative to an arbitrarily chosen zero point.

I recall having seen such things on the forum, but can't remember the name. Maybe people with better memory do.

16

Posyx is a system for indoor localization.