Hello
just finish to build a project with an little smartcar who can follow a path that you draw on you tablet.
thanks to a great tutorial and a great tutorial builder on the Instructable website
I would like that the car could recognize different location.
It would be nice some kind of sender (it need to be small) working standalone (not connected to a arduino) place somewhere in a room sending his location to a receiver place on the arduino-mega on the smart car.
maybe the sender/receiver (link here under) would do the job, but i don't know if it's necessary to connect an arduino to the sender and another arduino to the receiver (that would be bad, big and expensive)
http://www.dx.com/nl/p/mini-3-3v-rf-transmitter-receiver-module-433mhz-wireless-link-kit-for-arduino-3-3v-mcu-414004#.Vyupj3qJ5Zo
maybe it's better some kind of IR sender, like the IR sender from a robotvacuumcleaner, but i would like it work if the sender is covered by something (like clothes or garbage)
For this reason, I believe radio freqency is better
Do you have an idea?
Please explain what you want to achieve. The purpose of the Tx/Rx makes a big difference to what is recommended.
Weedpharma
The nRF24L01+ 2.4GHz transceivers are cheap and reliable.
I got my nRF24s working with this Tutorial
I suggest you use the TMRh20 version of the RF24 library - it solves some problems from the ManiacBug version
The pair of programs in this link may be a useful starting point for your project.
...R
I suggest you use the TMRh20 version of the RF24 library - it solves some problems from the ManiacBug version
Well 1st looks like you came here 1st 
I would suggest nRF24L01 as well but the RF24 lib is good as well using it with 1.0.5 IDE
Domino60:
but the RF24 lib is good as well using it with 1.0.5 IDE
What do you mean by "RF24 lib"? Can you post a link for the benefit of the OP?
Unfortunately TMRh20 calls his library by the same name (RF24) as ManiacBug did. I had problems with the ManiacBug version which are solved by the TMRh20 version and the code I linked to in Reply #2 will not work with the ManiacBug version unless the library is modified.
On my own PC I have renamed the TMRh20 library to avoid confusion.
...R
While thinking about this, I think you have to think this through. I have basically no knowledge of RF, so keep that in mind when reading this.
Let's assume you have 4 transmitters (each in their own room). And one receiver on the car. All those transmitters are transmitting 'their location' at the same time. If they are powerful enough, the car will receive all signals and still not know where it is. So you need to limit the output power of the transmitter modules and the sensitivity of the receiver; you might be able to achieve this when not using antennas on the modules.
The next problem will be to differentiate between the different transmitters. They need to transmit something unique so the car knows where it is. This will require some additional hardware.
I'm currently experimenting with http://wiki.iteadstudio.com/433Mhz_RF_Link_kit; they might behave similar to the units that you linked to.
One thing I've noticed during experimenting is that the receiver outputs garbage if the transmitter is not sending real data. Your receiving Arduino needs to be able to figure out the difference between garbage and real data. It can be achieved with hardware encoders / decoders or in software (e.g. using the RadioHead library; the software solution obviously requires a micro for the transmitter (it might be possible to do this with an ATTiny).
Maybe a solution with IR or light might be easier to implement, no idea.
What do you mean by "RF24 lib"? Can you post a link for the benefit of the OP?
Same URL you posted above
http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
If you scroll down to the Table : "Here are details of the Pinout and connections to Arduino (updated):"
6 column starting from the signal there is a "Arduino pin for RF24 Library" I use this library with arduino IDE 1.0.5 and I always use 1.0.5 because there is some old libraries that can't run on newest version.
Domino60:
Same URL you posted above
Sorry. My mistake. I thought you were recommending another library that I have not tried.
...R
Sorry. My mistake. I thought you were recommending another library that I have not tried.
Nah same old nice RF24 lib, i just use IDE 1.0.5 because for some reason is not compiling in the 1.5 IDE