I'm in the phase of designing a quad.....and i was wondering about the best and cheapest  way to communicate with it ?

also, while i was searching i found some guys controlling a car with 2 cell phones using DTMF , did anyone try that for a quad. ?

thanks 

DTMF is used for only mainly where coded control of unlimited numberof channels for only on/ off is used or for 12/ 16 channel simple on off control (still you cannot use all channels together like how you do in RC because DTMF decoder chip can recognise only one DTMF tone/ number at a time) Further  cannot be used for purely proportional control requirement like in RC controls. If DTMF is used for proportional requirements its going to make electronics more costlier but much much..... Much............... slower than the RC radio.

A big 'NO' expecially for highly responsive requirements of RC quad.

However if you make a fully autonomous and stable quad, you can use DTMF communication to feed the waypoints and altitude for its every next position it has to reach.

thanks sundaramvelar 4 ur reply

most people recommend xbee for that,but it's expensive....do u know of any other alternative?

Though I have done a lot of  complicated DTMF based  wireless projects, I have  not come across one for RC application.  However  I am very much sure a DIY project for DTMF based communication with an audio video transmiter receiver and stabilisation platform using Atmega & Ardupilot is very much possible.