Go Down

Topic: 433 vs. 433,92 MHz (Read 13772 times) previous topic - next topic

liptaka

Hello,

I have an automatic gate with controller working on 433,92Mhz.
Is it possible that it will communicate with the 433M wireless transmitte rmodule (connected to arduino) ?


mauried

Need more information.
The type of modulation has to be compatible, ie is it AM or FM.
Most of the common 433 Mhz transmitters used with Arduinos are AM , actually OOK, but still AM.
You then need to figure out what type of coding the gate controller uses, which can be easy or hard
depending on the Manufacturer.
If the gate controller uses a rolling code you will have difficulty using it with an Arduino.

Peter_n

The frequency is the same. When 433MHz is mentioned, they actually mean 433.92 MHz.

Shpaget

Slightly off topic, but why isn't it called 434 MHz?

Peter_n

Lazyness.
Although some call it 434MHz.

Double that frequency is called 868MHz by everyone.

Shpaget

That explains it, I suppose.

MarkT

433MHz is the name of the _band_, not the individual frequency or channel within the band.

The band itself has various band-plans in different territories, and IIRC spans 433.0MHz to
434.8MHz (band edges are never valid frequencies BTW).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

liptaka

Thanks for answers.
Actually my gate controller can be set between rolling code or fix code.
In this case I just need to "learn the code" ?

Peter_n

As mauried said in reply #1, it depends on the modulation and the coding/protocol.
Are you sure that it is your own gate ?

Some modern devices can have very difficult protocols, even if the modulation is just AM.

mauried

Even with a fixed code , learning it is the hard bit , unless you are lucky and can find out from the Manufacturer what the data format is, and they usually wont tell you.
You need some minimum hardware like a CRO of some sort, or logic anaylser to look at the data format.
Sometimes you can obtain some info from the ICs in the Transmitter, if you can see any markings on them.
A much simpler way is to pull the controller apart, and simulate the pushing of the buttons using an Arduino.
That way, you dont need to understand whats being transmitted.


KenF

Slightly off topic, but why isn't it called 434 MHz?
It's just a slapdash shortened form.  My first name is has actually got a double "N" so rounding it to the nearest character, the three letter equivalent should be "KEO". But it seems common practice to not round up, in such cases.

liptaka

Even with a fixed code , learning it is the hard bit , unless you are lucky and can find out from the Manufacturer what the data format is, and they usually wont tell you.
You need some minimum hardware like a CRO of some sort, or logic anaylser to look at the data format.
Sometimes you can obtain some info from the ICs in the Transmitter, if you can see any markings on them.
A much simpler way is to pull the controller apart, and simulate the pushing of the buttons using an Arduino.
That way, you dont need to understand whats being transmitted.


Thanks it is good idea.
I also found this page:
http://www.wes.id.au/2013/07/decoding-and-sending-433mhz-rf-codes-with-arduino-and-rc-switch/

Maybe I will give a try..


mauried

The RC switch library is designed to decode signals transmitted from devices which use a SC2262 / SC 2272 or equivalent encoder / decoder families.
These encoder / decoder chips are very common, but they dont support any kind of rolling code capability, so if your garage door does have rolling code capability , it wont be using these devices.
Your best bet is to pull apart the remote controller and try and identify whats inside it.


Go Up