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Nickorossa
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I would imagine the chip will just be a COB so you won't know whats really under there.
Reading Wireless Air Transmitter using Arduino
- Thread starter Nickorossa
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Frequency isn’t as important as the protocol being used, knowing the frequency does very little for you unless you an RF geek. Since it is unidirectional, it just broadcasts strings. If you identify the transmitter chip, you can just buy a matched receiver, likely available from digikey, hook the receiver up to arduino or whatever and start listening, knowing the readings from the computer, you can listen and figure out how to parse the data.
I saw this post and decided that since I have a pretty good spectrum Analyzer on my home workbench I would look and see what I can see at 38Khz. Well after half an hour of fiddling I see nothing! Even down at -188 dBm there is no signal coming from the AI module but my Teric is picking up the signal. I am starting to wonder if this is an RF signal or is it Acoustic?
dm9876
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Cool, though suprised you got nothing at all maybe we have wrong info about the particular frequency. I think at that these near VLF frequencies it is more in the magnetic domain (near field) and need a coil to pick it up. What did you do for an antenna. I think these devices are using a tuned coil on a ferrite rod for their antenna.
I thought the same thing but then I did a quick look and the FCC is also involved in licensing sonar equipment, they probably have a say in anything that involves wireless communication. I can tell you one thing, this thing is not putting out an RF signal unless the frequency they state is not accurate and I doubt that is the case.
Yes I was using an antenna but of course it was not a resonant antenna. If it was an RF signal the DC could never fit a resonant antenna for that frequency. At -188dBm I would be able to see a fly fart at 100ft if he farted RF gas
. I scanned from 20Khz to 50Khz just in case and I found nothing but noise. I locked onto 38Khz and saw nothing. I tried listening on AM and FM and got nothing on the headphones even as the Teric updated the screen. I would have expected the signal to be a CW type signal but nothing. I did see a post one time where another member also looked for the signal and found nothing. I just figured he did not have the right equipment, guess I was wrong.Unfortunately I don't have any kind of Mic that can pick up audio at 38Khz.
It is authorized under DCD- part 15 Low Power Transmitter Below 1705 kHz. See https://fccid.io/MH8A.
One of the links goes to https://fccid.io/frequency-explorer.php?lower=0.03800000&upper=0.03800000, where the waveltngth is given. It is RF, not acoustic. Sorry you couldn't hear it.
I was not listening for the carrier
I was listening for the modulation! I expected some sort of distortion sound from the pulses but heard nothing but steady static and of course no signal on the screen.My Spectrum analyzer can go from 9Khz to 3.2 Ghz and there is nothing on 38Khz.
Unlike most FCC registered devices this one has no real documentation on it, other than the link you posted which I had already read. I do see that the same company has documentation for some Oceanic Bluetooth device and that has the expected PDF files. The AI device was submitted in 1995 which is prior to the full blown internet, so i suspect the paper work is in a file cabinet with the FCC. If anyone has some ideas I am willing to try them.
Open one up, the numbers on the chipset will tell you everything you need to know. I'll even volunteer to do it if someone gives me a transmitter. finding a transmitting frequency won't help much at all, there is a lot more going on there you could never unpack by knowing the frequency.
Example, lets say a chip in there has a number on it that corresponds to a transmitter chip that uses nrf24l011 protocol. All you have to do is buy another chip or dev board with a chip that uses that protocol. You may need to write a program to go through the channels and figure out which one(s) the transmitter uses but that's not very hard. after you establish comm, you can start collecting data and since you will know what it is supposed to be, you can start identifying and parsing it so you can read and use it. It is extremely unlikely that the transmitter uses it's own unique protocol/ chips to communicate.
Example, lets say a chip in there has a number on it that corresponds to a transmitter chip that uses nrf24l011 protocol. All you have to do is buy another chip or dev board with a chip that uses that protocol. You may need to write a program to go through the channels and figure out which one(s) the transmitter uses but that's not very hard. after you establish comm, you can start collecting data and since you will know what it is supposed to be, you can start identifying and parsing it so you can read and use it. It is extremely unlikely that the transmitter uses it's own unique protocol/ chips to communicate.
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