hai... people
we are making a spy robot which is our final year project which is a prototype of military spying robot.
the questions are as follows

1. we are using a transmitter and recevier circuit which is taken from remote control toy car we want to know what will be the modulation of it?? whether it is AM/FM??the ic in the circuit is TXRX-2B...

2. what is the maximum ferequency and range in wireless transmittion??
please reply... waiting for the reply fast....

 

Offering gold makes fast, slow is free.

 

1. the common practice is that people use fm modulation. the ic wouldn't be critical, it could be of many kinds.
2. usually the frequencies are 27mhz and 72mhz. there may be other frequencies as well.
the range is usually under 5km radius at best, but it depends on the signal strength of the transmitter.

 

Remote toy cars in the US are usually on 27 or 75 MHz. The 72 MHz band is for aircraft. Some countries and areas, such as the EU and England, use different frequency assignments.

As for modulation, FM is most common for mid to high end, which are also almost all 75 MHz (for cars). At the low price end, one still finds AM. The 27 MHz units are usually at the least expensive end, and a lot of 27 MHz stuff is on AM. Some is even super-regenerative, not superhet. The range is low and selectivity is poor for most of the 27 MHz units with which I am familiar.

John

 

There used to be some R/C stuff running at 49 MHz. For servos, it's a kind of PWM.

 

I'm going repeat my query from the last time you asked about this: What is the manufacturer and model of the toy car you pulled the circuit from?

 

receiver circuit which is taken from remote control toy car

From my experience of R/C equipment, I find that transmitters for radio controlled toy cars tend to be dodgy. Over time they become somewhat unreliable, as in a drastic drop in range and response time in comparison to when first used.
When you say toy car, I presume it is lower end/cheaper model, In this case, with regard to range you would be lucky to get 50metres.

For small projects there are many reliable transmitter/receiver units out there, for example Futaba and Hitech have some reasonably priced starter kits, which can be picked up on Ebay.

At least that way you will know what you are dealing with for definite.

NM

 

NM2008 is right on with his advice. Don't overcomplicate your project, you will definitely run into many unexpected and more application-specific problems as you move along, which you should expect ahead of time by making things as simple as possible.

Steve