Recommendation on 433Mz devices

Projects Discussion and Showcase Home Automation and Networked Objects
#1

I've been doing some testing with controlling/reading certain commercial 433MHz appliances at home (doorbell, light switches, relays for controlling fans etc), using cheap arduino "compatible" 433MHz transmitters/receivers (MX-05V). After some tweaking and troubleshooting I'm able to both pick up the signals (from doorbell) or transmit signals (to switches/relays) with some success, but I still have problems with the receivers. It seems that when not receiving anything they automatically increase the gain, and by some reasons I don't fully understand seem to start transmitting noise in the same process. For instance if I power up a receiver listening for signal from the doorbell, this effectively jams my car's locking system.

From what I understand these cheap rf-modules also suffer from DC signal bias, are there arduino compatible modules that do not suffer from this?

#2

The cheapest 433 MHz receivers use a superregenerative receiver, which actually emits 433 MHz signals.

Try a superheterodyne receiver like this and the problem should go away.

Note: look for the metal can. Lots of receivers are advertised as superhet or superheterodyne, but are not.

From what I understand these cheap rf-modules also suffer from DC signal bias,

I don't know what you mean by this.

#3

jremington:
The cheapest 433 MHz receivers use a superregenerative receiver, which actually emits 433 MHz signals.

Try a superheterodyne receiver like this and the problem should go away.

Note: look for the metal can. Lots of receivers are advertised as superhet or superheterodyne, but are not.
I don't know what you mean by this.

I have one of these receivers as well. I think I encountered the same problem, but I will have to check again.

In my understandign DC bias is how it adjusts it's gain on the premise that the signal is expected to be equal amounts of HIGH and LOW (e.g manchester encoding).

#4