What is wrong with my 433MHz transmitter?

Hardware
1

I have a Westinghouse Model #28070T radio transmitter remote and 3 corresponding outlets that i got from Target a few years back when they were getting rid of their Christmas stock.

I just recently ordered a generic 433 MHz transmitter and receiver set, and have hooked them up to my Pi.

I used this on the Pi AND RF_Sniffer on an Arduino Uno to pull the codes off the remote and make sure I was getting the same ones. (rfrx.py is a little confusing to look at.) Both sets of codes I got matched.

So the receiver is definitely working.

I just don’t seem to be able to transmit anything. If I run the rpi-rf_receive and rpi-rf_send scripts at the same time in different terminal windows, something clearly goes wrong.

transmitted:

$ sudo python3 rfsend.py -t 1 1330315703
2017-06-25 01:06:48 - [INFO] rfsend: 1330315703 [protocol: 1, pulselength: default]

received:

2017-06-25 01:06:48 - [INFO] rfrx: 4104 [pulselength 136, protocol 3]
2017-06-25 01:06:49 - [INFO] rfrx: 67108864 [pulselength 354, protocol 1]
2017-06-25 01:06:51 - [INFO] rfrx: 4 [pulselength 1851, protocol 4]
2017-06-25 01:06:51 - [INFO] rfrx: 4 [pulselength 1445, protocol 4]
2017-06-25 01:06:52 - [INFO] rfrx: 64 [pulselength 1330, protocol 2]
2017-06-25 01:06:53 - [INFO] rfrx: 8 [pulselength 1343, protocol 2]

And obviously, if the transmitter were actually transmitting the necessary code, my outlet would flip on and off, which it’s not. (To save time and embarrassment, yes, the outlet is plugged in.)

I’m kind of out of ideas on this one.

2

Transmitting needs a fair bit more power than receiving, so first check your power supply. The official RPi supply will probably be enough, but anything less than that will probably fail.

3

It should be ok. I’m using this supply from Ikea.
http://www.ikea.com/us/en/catalog/products/10291881/
Has an output of "max 2400mA per USB outlet.

Surely a difference of 100mA wouldn’t cause this?

Would it be a stupid idea to remove the power and ground leads from the transmitter and power it from a separate supply?

4

Well, I tried anyway and it doesn’t work.

5

Did you solve your problem? It is 4 weeks ago, but I do not see any solution.

I am currently using the generic 433MHz transmitters (like this ) with rpi-rf without any problems.

These transmitters are really weak in terms of signal strength. Adding antennas may solve the problem.

I added just a piece of copper wires (approx. 17cm long) to both components and now I am able to reach any outlet in my house.

HTH

6

I’m using a USB 433MHz transmitter on a VM, so full fledged server with more than adequate power supply… once a week or so it craps out as well. I even tried plugging it into a powered USB hub.

I suspect these things are just terrible at power management.

7

Not yet. I did get a different RF transmitter and receiver kit. The new transmitter definitely transmits something just not the code I assign to it for some reason.

https://www.amazon.com/gp/product/B01GFVN99Q/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I can try attaching a longer antenna, but I really don’t think that’s the issue. The outlet I’m trying to control is less than a meter away.

I think I’m going to put the receiver on an Arduino, run a sketch to see what the hell this thing is actually transmitting.

Is it possible that when these scripts identify the code as being Protocol 1 at pulselength 405~ my remote is actually transmitting something completely different?

8

So i have the same problem:

Got cheap rf 433 outlets wich work great with the rf remote.

Pi with rpi-rf and the cheap eBay Transmitter and receiver.

I listen to all the signals with the receiver and get a good constant result. But then when i transmit the signal the outlet doenst do anything…

So i opend a new window to my pi and i see that my transmitter is receiving.

The problem is the pulselength is off by 5 or 6. So i tried compensating it by typing a lower pulselength number ( receiver says 319 when i push the button on the RF outlet remote).

Then the receiver does see the exactly correct P-length send bij the cheap transmitter!! But nothing happens with the outlet…

Knipsel
Knipsel1678Ă—409 216 KB

Its a Raspberry 3 with the original 2.5 a power supply.

Al the stuf is on a table not more than 15 centimeter away from each other.

What could this be? And how can i fix this

9

I still don.t know. I now have some 433 MHz door sensors that send their signals to an Adafruit Feather HUZZAH and relay the signals to the Pi via MQTT. It doesn’t broadcast 433 MHz to anything else though. Not sure how it would take that.

And I have since set up a couple Sonoff outlets which are working very well, and are cheap.

If you have a transmitter and a receiver, maybe some sort of analysis should be done. If there is some sort of signal generator, compare the input and outputs…I dunno. That’s where my mind goes.

1 Like
10

I have exactly the same issue, this time with a projector screen. I have successfully sniffed the remote codes, correctly added a switch in HA and the switch works - I can tell the tx is sending the correct signals as the rx can see them. But the screen doesn’t pick them up. They are within a metre of each other. Did you have any luck VGE?

11

No succes yet. I orderd a beter version of the tx and rx. it could be the products are not open for this protocol.

Im thinking of buying some KlikAanKlikUit switches wich are widly used for this method. If they work i know its in the device and not my Pi + rx + rf setup.

12

No succes with the new RX tx set.

13

I would seriously consider attaching your RF units to a NodeMCU and loading OpenMQTTGateway on it. A similar setup is working for me that way.