chui

Hi,
Here is a circuit for a remote-control (Transmitter&recivr)
with 4 channels(, using DTMF).

someone told me the transmitter is not good anough, I need it for a cartoy
si I dont need a too long distanse one.

Please tell me what do you think about the circuit..

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SteveM

Take a look at http://www.circuithut.com/index.php?...remote_control this is a simialr circuit based on a DTMF TX/RX. It was used for controling a toy car.

Cheers

Steve M

chui

There is something I didnt understand,
Does those circuits have the FMtransmitter/reciver in it,
or shuold I add it?

(what is "FM TX")

tnks.

Megamox

The first circuit has the transmitter at the output, its the transistor configuration with the inductor and capacitor on the collector connected to the antenna. The term's RX and TX mean receiver and transmitter respectively.

Sebi

The frequency drift can be a problem. You should add a circuit for carrier detection, it can reset all outputs, and the toy (car) stopped, don't go away when carrier lost.

eblc1388

Hi chui,

There is a potential problem in your original FM transmitter circuit. The tone output of the dialler IC is much too strong for input to the FM transmitter. You need to reduces it using resistors. Please follows the weblink posted by steveM for an example.

Also C3 across the transistor C-E pins is 10n which is 10,000pF. This does not seem right.

__________________
L.Chung

David Bridgen

I think having a connection to earth from the car would be inconvenient to say the least, and not much better having one from the controller either!