i actually completed making the RF car circuit i made it form this diagram (http://www.vishaworld.com/product.asp?2170) i actually brought the kit which did not contain the relay board the motors etc but now i am having the problem of connecting the motors to the relay
i have got the relay working but having some problem with the power
i am using 6v relay and 12v motors the transmitter uses a 9v battery
and the receiver uses a 9v i also have a 12 battery which they told me to buy
plz help

 

i could not see the schematic as it did not open, i dont know what the reason is, i doubt it on my windows7 ie9 duo.

But on the receiver board it was mentioned 9-12v , so connect 12v to receiver board. Then your motor will anyway work as you got it 12 v. Now the relay may drain your battery while unnecessarily getting over heated as it it 6v.

you could pssibly do one of this:

1. replace with a 12 volt relay
2. If you have one more 6v relay, just connect them in series
3. connect two white LEDs in series with the relay it will ward-off atleast
4-5 volts and will give some asthetic edge to your ckt
4. Cnnnect some 10 diodes in series alongwith the relay to get a drop of 5-6 volts.

But before this check the voltage at the relay coil points on the board , by disconnecting any one lead or both to know what voltage your getting at those points.

 

there is not one relay but there are four relay
the place from where i bought it i was told to connect a 9v to the receiver +ve of 12v to the relay board -ve to the receiver with that of 9v battery but there is no wire going to the NO,NC,COM of the relay the +ve of 12 goes to the coil of all four relays -ve comes from the receivers out1,out2,out3,out4
plz help

 

The link comes up fine for me in Windows Vista. I have the Win7 upgrade but haven't had the need to put it on this laptop yet as Vista wasn't as bad as most people say it is. I'm still a fan of XP though but the added security features incorporated into Vista and Win7 have come in handy for newer users and especially in my case where I've been slowly trying to teach my 80 year old mother how to use a laptop I got for her earlier this year. She can't install anything unless I allow the administrator privileges and she doesn't know the password.

To answer your question is tough without more knowledge and some pictures of where you're at will be difficult. Can you take some pics and hand sketch out a bit of what you've already done?

 

here i have uploaded some images have a look
http://img695.imageshack.us/i/motorsh.jpg/
http://img153.imageshack.us/i/receiverp.jpg/
http://img143.imageshack.us/i/transmiter.jpg/
http://img405.imageshack.us/i/relayfront.jpg/
http://img811.imageshack.us/i/relayback.jpg/
http://img826.imageshack.us/i/relaytomotor.png/
now the problem is that to move the car in any direction two relays must work form the four relays
they consume about 12v means a need another 12v battery which will increase the weight and size of the car
is there any thing else which can be used instead of the relays some thing which consumes a little voltage

 

Yes, you can use power MOSFETs and MOSFET H-bridges. Sure would simplify your design by around 100%

 

i like what you said but it also aroused a lot of question in my mind that what will be the things i will need,circuit diagram etc and i goggled around and found a tones of info on MOSFET but can i switch it on by ground because my out put pins give ground to the relays the positive is direct from the battery to the relays i will show you
http://img704.imageshack.us/i/relaytomotor.png/
here when any switch is pressed in the transmitter any out put pin gets grounded and the relay is switched on and one set of motors start (reverse or forward)so my question is can i use MOSFET in this case ???????????????

plz help i am not to good at electronics you can say i am just a bigginer
till now i made this circuit from the papers given but there is no info of the relay board and the motor connection

 

plz help i cant find any thing