Hi
I have the R433A receiver transmitter pair and they won’t communicate. This should be very easy as your instructions imply but I can’t get it to work. Could you give me some tips
Need help please
A) http://www.catb.org/esr/faqs/smart-questions.html
B) What’s an R433A?
skimask:
A) http://www.catb.org/esr/faqs/smart-questions.htmlB) What’s an R433A?
Yep.
Smell a drive-by-poster…
The R433A is a variant of the well known R433. Surprised you guys didn’t recognize this!
I thought it was the refrigerant that replaced the refrigerant that replaced Freon ?
Or perhaps the Tx/Rx pair akin to
https://www.sparkfun.com/products/10534
A link might have been nice or some inkling of his setup and what it was he did and didn’t observe.
Ya, the first google hit on R433 is a road in Ireland and no hits for any type of RF module.
I think I need help with filtering the noise that the pair pick up. I am sending a 1 from the monitor that will light an led. 0 turns it off. The pair erratically work. Noise I think
You should really search the forum. There are multiple posts dealing with proper use of OOK modules. You also need to work better on the communication skills. What have you tried? How did you try it? Why do you think it worked (or not)? Provide good detailed explanation/description of your problem and you will receive good detailed answers/solutions.
Some useful links (take the time to read so you can ask more meaningful questions - and get more meaningful answers):
http://winavr.scienceprog.com/example-a … llers.html
https://forum.sparkfun.com/viewtopic.ph … 73&start=0
https://forum.sparkfun.com/viewtopic.ph … 07&start=0
a cheap on-off-keying transmitter is either on or off. Like Morse code. Like binary bits 101010111000. On, off.
When off, the receiver gets no signal. Only noise. That’s normal.
with cheap OOK radios, YOU have to learn how to send data, where, essentially, each byte (8 bits), or each stream of other number of bits, does not have any streams of lots of 0’s in a row. That is, the ratio of transmitter on to transmitter off is as close to 50/50 as you can get. To do that, a method called Manchester coding is often used. It’s simple to do in firmware. This and many other grunging low level things have to be done to make a $2 radio work. A $10-20 radio does all this bit fiddling, and also byte fiddling and error correction and data addressing for you.
People who use $2 radios are either unknowing beginners or smart manufacturers who know how to do bit fiddling/wireless and they want the cheapest hardware. OOK was used in older garage door openers, but even these are now using a much better radio, and clever security coding.
This question on OOK comes up from beginners once a week.
In addition to all the good info above, let me try to give you 1 reason why you see what you see. The usual OOK receiver basically asks the question “Am I “seeing” sufficient RF energy to say the transmitter is on”. If the answer is “yes” then you get a logic 1 output, otherwise it’s a 0. These receivers will have automatic gain control, where the gain of the receiver is turned up (to some max amount) in order to detect a weak RF signal. Alas this high gain also amplifies noise and sometimes noise is above the “yes” threshold. You may think that’s silly but it does allow you to receive a weak signal at the cost of sometimes falsely getting some bits.
Sometimes there will be other transmitters that overlap the same RF bandwidth that you’re using and voila, a logic 1.
Sometimes there are other transmitters that aren’t in your RF BW, but are so strong and close enough that the receiver outputs a 1.
That’s why you need to do all the functions mentioned so above, so you can distinguish not just random noise but other interference from your intended signal.