4 Cannel 433mhz transmitter/receiver

Thread Starter

John Berry

Joined May 17, 2016
72
20190904_211833-928x1650.jpg 20190905_025517-928x1650.jpg Screenshot_20190905-021355_Drive.jpg Screenshot_20190905-025417_Drive.jpg Hi folks, I have just decided to use my transmitter/Receiver module for a basic led set up.
Everything was connected to the bread board, powered up and nothing happened! so I checked with my multimeter to confirm that I have a good 5v volt supply and that ground was also good.
I then connected my DMM to the outputs one by one whilst pressing the remote buttons and all were dead?
I have looked at the rear of the rx and noticed that there is a big blob of solder bridging A6 to 5v could this be the problem. ?
I have attached some photos to hopefully help.
Thank you very much John :)
 

RPLaJeunesse

Joined Jul 29, 2018
61
Interesting, just ordered one of these last week. Which PT2272 version is on the board? Hopefully M4 or L4, or a part with a higher number. When you press a key on the transmitter you should see the data stream come in on pin 14 of the 2272. With a valid address match pin 17 should go high, but it will only be a pulse so it may come and go quickly. If that doesn't happen then you need to check the address bit values to make sure transmitter and reciever match. If pin 19 does go high then you need to use that as a flag to look at the D0-D3 lines. On the M4 version these are momentary and only valid while pin 19 is high.
 

Thread Starter

John Berry

Joined May 17, 2016
72
Interesting, just ordered one of these last week. Which PT2272 version is on the board? Hopefully M4 or L4, or a part with a higher number. When you press a key on the transmitter you should see the data stream come in on pin 14 of the 2272. With a valid address match pin 17 should go high, but it will only be a pulse so it may come and go quickly. If that doesn't happen then you need to check the address bit values to make sure transmitter and reciever match. If pin 19 does go high then you need to use that as a flag to look at the D0-D3 lines. On the M4 version these are momentary and only valid while pin 19 is high.
Hello and thank you very much for your reply, I am sorry that I have not replied sooner but I have been very poorly. I have been diagnosed with Prostate cancer.
I've not had chance to try your recommendations yet though.
Thanks again John
 

RPLaJeunesse

Joined Jul 29, 2018
61
John, sorry to hear about the health issue, best of luck with that.

I have my fob and receiver set now, the receiver uses the M4 version chip. I have no blob on the A6 pin, that could be the issue with yours. On mine the VT line goes high as long as any transmitter key is pressed, while D3..0 indicate which key is pressed. All D3..0 are low when no key is pressed. The D3,2,1,0 map to buttons C,A,D,B respectively; not very logical but usable. I tried loading one output with a red LED plus 270 Ohms, that worked but really loaded the line down. No load it runs 5V, with a 1.45mA load the output sags to 2.3V. So I'd say the PT2272 was not really intended to drive an LED directly. If you hope to drive an LED to 10mA, consider adding a small NFET (2n7002, BSS138, etc.) as a boost transistor. FWIW my receiver craps out with the 5V supply pin down about 3.5V. That's a pretty good safety margin for a 5V device.
 

DickCappels

Joined Aug 21, 2008
5,873
The blob of solder bridging A7 to 5V is probably there to set the address of the receiver. This is a very common method, though this one looks much neater than those I have seen.

I am sorry to hear of your prostate cancer.
 

Thread Starter

John Berry

Joined May 17, 2016
72
The blob of solder bridging A7 to 5V is probably there to set the address of the receiver. This is a very common method, though this one looks much neater than those I have seen.

I am sorry to hear of your prostate cancer.
Okay thanks very much for your comments.
John
 

Thread Starter

John Berry

Joined May 17, 2016
72
Thanks again, what does this mean in layman's terms to, set the address of the receiver?
Cheers John
 

DickCappels

Joined Aug 21, 2008
5,873
I remember back in the 1960's as teenagers we got our hands on a garage door opener remote control, and we took off one night and drove around town turning the transmitter on as we past houses. Many garage doors opened in response to the signal and it was thrilling. Not nice but we were kids. Garage door openers and in many other remotely controlled devices now have various means of making them ignore signals to which they are not supposed react. For this purpose, transmitters and receivers have a means of programming a "code" or address so that the receivers will only respond to transmitters sending the same code. That way, when I open the gate across my driveway my neighbor's gate stays closed. The same with our doorbells.
 
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