Indoor delivering robot- How can I do it?

I’m trying to make an autonomous robot to deliver mail inside an office.
Which is the better way to know the position of the robot and the guide it around the office?
I though to make with IR sensors, nut I don’t know.
Is it possible to make it with GPS or any other thing?

I need ideas, I’m a bit lost.

Thanks

Generally GPS doesn't work too well indoors, and may not be accurate enough anyway.

I once built a line-follower, with a bar-codes next to the line indicating branches (it was assumed nothing permanent would be placed on the lines), and ultrasonics to avoid temporary obstructions.

Thanks for your reply. But I do'nt want that the robot follows lines. So any other idea?

Thanks a lot

You could set up a form of ultrasound indoor GPS, but you'd need a lot of beacons, most likely, and it probably would suffer from reflections, producing inaccuracies. Or you could use optical beacons. Or you could use odometry, but this could suffer from inaccuracy if you have different floor coverings. Depends on the size of your environment, and your cost/time constraints.

What ideas have you had?

My time is limited and one of my biggest constraint is the money.

I though to use the IR information to locate the robots and give it the commands to move.
What’s odometry?

The environment pretends to be an office located in one floor with to rooms. like the draw attached.

draw.jpg

What's odometry?

http://bit.ly/zZGnlR

Second time today.

carme: I do'nt want that the robot follows lines.

Given the constraints you've described, a line follower sounds by far the most sensible approach. A fully autonomous robot capable of locating and orienting itself and finding a route for itself will take a lot more time and money. It'll also need something a lot more powerful than an Arduino to control it, I expect.

My time is limited and one of my biggest constraint is the money.

Then you really should pick another project. This one is not for you.

Thanks for your opinion. I decided to star with the line-follower robot. What do you thing is better to use, bar codes, colored lines or RFID to indicate different ways?

I tried to find RFID manufacturers to know prices but I couldn't find anyone. Do you know any barcodes readers that can work with arduino?

And another question, if I want to do it with and arduino mega 2560, which of the options to recognize routes is better?

I'm asking all these stuff because it's my first robot and I'm a bit lose.

Thanks

In indoors training ranges and similar, there will be magnetic sensors for position. However, those are a bit sensitive to too much hard iron, so if you also use steel for your robot chassis, that may not work so well.

If you want to do image processing, you can put QR codes on various walls, and have the robot see them, and determine where it is based on which it sees. That requires a camera (or more) and a reasonable amount of DSP (such as BeagleBone, Raspberry Pi, etc).

In general, though, if money is a constraint for you... robots probably isn't the right project. Unless you happen to have unlimited access to a machine shop and free stock materials :-)