sir in this circuit in the reciver part.
its is mentioned FM reciver.
how to connect the fm reciever to this circuit
i mean the fm reciever has the speaker connected to it.do i hav to connect that wire to the dtmf reciver circuit
i purchased the fm reciever from the market .
Oh, you mean broadcast FM radio?, you didn't make that clear, I presumed you meant licence free FM data modules. You can't easily do it with audio radio gear, and you shouldn't be trying to!.
The single transistor "FM transmitter" is not good.
Its antenna is connectrd to its LC tuned circuit so its frequency changes when anything moves close to or moves away from the antenna.
It doesn't have a voltage regulator so its frequency also changes as the battery voltage runs down.
It has low power so its range might be only across a street.
Oh, you mean broadcast FM radio?, you didn't make that clear, I presumed you meant licence free FM data modules. You can't easily do it with audio radio gear, and you shouldn't be trying to!.
ok
can i use the remote door bell and connect its tranmitter with dtmf ic um91214b
and its reciever with ic 8870.
y i want to do this is bcoz the door bell available in the market can b operated with any of the transmitter so connecting the dtmf chip with it can make 4 diffrent tranmitter .and secondly the doorbell ois a very cheap option
what????? sorry but you let me on in the same place... can you explain with another word..???
PD: without PIC will be better, but is that make the proyect more easy and small i will need your help...
In your profile, look at the left of each post, most people have their location displayed - that way we know where you are, country is often enough. There may be someone nearby who could program you one - as it is we don't know where you are, and it's a LOT easier for someone in the same country to send you a chip.
The single transistor "FM transmitter" is not good.
Its antenna is connectrd to its LC tuned circuit so its frequency changes when anything moves close to or moves away from the antenna.
It doesn't have a voltage regulator so its frequency also changes as the battery voltage runs down.
It has low power so its range might be only across a street.
well thanks a lot for this useful tip. .
can u suggest any other transmiter circuit and also tell that
where to connect the pin7 of the dtmf generator UM91214b
to the TRANSMITER
here is the ckt. . broken link removed
and how to connect the FM reciever (mentioned in the reciver unit of the circuit in the link ). . .do i simply connect the two wires that are connected to the speaker of the FM reciver available in the market
one more question
the cheap remote door chimes which are available in the markets do they also works on FM or they use some other mode.
Most FM transmitter projects have a low level microphone input. The DTMF generator has an output level that is much higher and will need an attenuator. There are hundreds of FM transmitter circuits and kits available.
how to connect the FM reciever (mentioned in the receiver unit of the circuit in the link ). . .do i simply connect the two wires that are connected to the speaker of the FM reciver available in the market
A radio speaker output level is too high for the circuit. The receiver will need to have the ratio of its R4 and R5 adjusted to reduce its gain and an attenuator is needed to match the output level of the radio.
the cheap remote door chimes which are available in the markets do they also works on FM or they use some other mode.
so can i use the encoder and decoder through AM transmitters also(remote door bell)
bcoz the doorbells available in the market can b operated through each others remote.
wat i need is about 12 relays to operate remotely through 12 transmitter but single reciver with 12 relays (each for respective transmitter)
can i use AM for this??