RF Transmitters and Receivers?

[jeff77789]

I've been trying to use this pair of RF transmitter/receiver:

https://www.sparkfun.com/products/10534
https://www.sparkfun.com/products/10532


does anybody have any experience with what type of signal it actually sends/receives?

you see that in the datasheet for the receiver you have a digital output and a linear output as well.

I sent a pwm type output through this and it looks like it kind of successfully transfers but the signal is very noisy, disrupting the pwm signal. i dont think an analog voltage signal would transfer

thanks

 

[myfaithnka]

jeff77789,

this kind of Transmittors-recievers are very commenly used for control applications.I know this modules well.

It could be easy for me to help you if i know what s your requirement.

this rf modules can be used easily with HT12d,HT12e ICs,they are CMOS.

regards.

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sorry,
the ics are,

ht12d and ht12e.

typing error.

 

[FvM]

"Linear" output doesn't mean that the module is intended to receive analog signals. The module pair is able to transmit digital data with balanced duty cycle, either remote control encoder data or manchester encoded serial data streams.

 

[jeff77789]

jeff77789,

this kind of Transmittors-recievers are very commenly used for control applications.I know this modules well.

It could be easy for me to help you if i know what s your requirement.

this rf modules can be used easily with HT12d,HT12e ICs,they are CMOS.

regards.

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sorry,
the ics are,

ht12d and ht12e.

typing error.

I am actually using this with the MaxBotix ultrasonic sensor where I have a PWM output, Analog output and an inverted digital signal at 9600 baud

 

[jeff77789]

okay so i finally figured out to find a digital signal to send through these. there is another problem that comes up:

1. the signal being sent to the transmitter is 9600 baud which is 2x the 4800baud for the tx/rx (which i do not know if it affects the signal any)

2. when i view the signal, it is very noisy and it looks like it is just random numbers. the thing is, if i turn off the Tx, the values stay in their random state and it looks like there is no uniformity

 

[myfaithnka]

Pls share your test circuitry,for clarity here.

 

[noxx]

hello.. i have this circuit of an fm transmitter.problem is, i can't explain how L2-C9 & L3-C12 seem to be doing the work of tuning. can someone here help me explain? I'l remain grateful.

here is the image:

 

[jeff77789]

Now I am at the point where i can send a digital signal at 4800 baud through these sensors.

The thing is, If it send "123" on the other side, i rarely ever get the "495051" sequence (refer to ASCII table)
there is no encoding for this signal and i am not quite sure how to "encode" it either.
the accuracy rate is less than 10% and I have no Idea why the signal is so "noisy"

is there any way i can improve on this?

 

[myfaithnka]

Jef77789,

how can i help you without knowing the method you use to interface this modules...pls mention the circuit you use.

Embedding data in to noise is all it does actually.

 

[jeff77789]

Jef77789,

how can i help you without knowing the method you use to interface this modules...pls mention the circuit you use.

Embedding data in to noise is all it does actually.

as of right now i am using the default software.serial library used for the arduino connected directly to the Tx
(i believe this is called something like an UART)

 

[Jestin_cubetech]

try Manchester encoding.

HT12E HT12D is a easier solution..

 

[FvM]

try Manchester encoding.
HT12E HT12D is a easier solution..

Apparently the OP intends serial data transmission. HT12x isn't an option in this case. It should be mentioned that the Arduino code examples provided by Sparkfun are implementing a Manchester-like data encoding.

 

[myfaithnka]

if you are using arduino, its easy to interface.

i will get back to you in detail...pls be patient.

 

[noxx]

pls can someone help me with answers to my question above?

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pls can someone help me with answers to my question above?

 

[myfaithnka]

Jef,

there is this library called virtual wire,are you familiar with it ?