RF, I have problems

M

moonstreat

New Member
Hello, I need your help too!

I bought this modules tx and rx of radio frequency:

https://www.electro-tech-online.com/custompdfs/2010/03/54125.pdf

https://www.electro-tech-online.com/custompdfs/2010/03/54128.pdf


I rode them along with the decoder and encoder (HT12D; HT12E) and I am not able to make communication .. is very strange .. do not understand why this happens ..

when I turn on the receiver scheme .. I have the LED connected to output HT12D is always lit ..

need of your suggestions to solve it ..
 
Forget about the HT12D for a moment. Do you see the data at pins 6,7 of the RX when you key the TX on/off?
 
moonstreat said:
Yes, I have the Tx powered with 5V, the output pins 6 and 7, deume 3.65V
Click to expand...

If you turn TX on, what is voltage at RX6,7?
If TX is off, what is voltage at RX6,7?
 
I only have connected the RX, I have nothing on ...

the outputs of pins 6 and 7 of the Rx, I have 3.65V
 
Last edited:
Is the TX and RX on the same frequency? i.e. 433MHz?
What antennas are you using?
 
Turning the TX on/off means leaving it powered, and then applying a keying logic signal to the Data Input (pin2). Is that what you are doing?
 
Last edited:
I have the TX and RX on my plate test ..

and both have fed as the datasheets!

I see my multimeter the voltage of the output pins 6 and 7 of Tx and gives 3.65V, and the output

Pin 2 RX gives 5V, if I get my TX plate tests, does not alter the voltagemd and output Pin 6 and 7 RX
 
If you monitor the current going into the TX, does it follow the Data line if you make it go low/high?
 
moonstreat said:
I changes the current in my power supply .. and the voltage output of the RX was the same and did not change
Click to expand...

That likely means that the TX is working. Recheck the connections/power on the RX. Disconnect 6,7 from the decoder chip when checking to see if the RX sees the TX being keyed On/Off

How far apart is the TX and the RX? are they sharing the 5V supply? if so, try using an isolated supply for the TX/
 
Last edited:
it seems that they do not communicate with each other! I measure the output voltage of the pins 6 and 7 and RX is always the 3V, I do not understand this! that I will not have antenna?
 
The TX may be too close to the RX. Try moving the TX across the room, or even further. Seems like someone else had that problem recently.
 
Ok, I think I just figured it out. If you look at the RX data sheet, it says that the min data rate is 200Hz (max is 3000Hz), so just keying the TX on and holding it will not produce an output at the RX data pin. Can you use a pulse generator to key the transmitter on/off at ~1000Hz?
 
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