Hi Gang,
there is a interesting project :
[login to view URL] offers a kind of data-transmission over a audio channels. There
are also smartphone Apps available - see [login to view URL] So basically you are
able to transfer short messages between smartphones using the microphone + loudspeaker
over a short distance.
The scope of the project is to built a similar think (just the audio transmission
solution, not all the other rest).
We are looking for a smartphone-to-smartphone audio communication over the audio channel that
sounds like "birds tweeting" while transmitting. Pls try the above smartphone
Apps to see what I;m talking about.
Technically considered this is a :
- FSK modulation (but I;m open for other ideas)
- 50 Bits of data (in general only few bytes should be transmitted, maximim transmission time just a few seconds)
- Reed-Solomon Codes
- See for details [login to view URL]
- The parameters does not need 1:1 like chirp.io. We are not looking for a "copy", just a kind of inspiration.
The real challenge on this task is to make the transmission sound like birds tweeting.
One aspect that also [login to view URL] has used is to use "puretones" that are known from the
"music" notes - [login to view URL] But there is more.
The delivery goal would be :
- A working code for transmitting of arbitrary data using a audio interface (one way, A to B, B to A is not required)
- Nice would be a Java Code that runs on Android, but I;m open for other solutions.
- The usage of Reed-Solomon Codes for error corrections (e.g. [login to view URL])
- Signal/Noise consideration (evtl. some Matlab Code for simulations ?)
Please bid only when you know what would be required. This means you are potentially a
export in the high-frequency domain, you know about topics like DSP, FFT, digital filtering, etc.
The goal is not to have a "only" a FSK based transmission using from A to B, but while transmitting
the user has the impression that some birds are tweeting.. :-)
Cheers,
jj
Some another useful links :
[login to view URL]
[login to view URL]
Hello! I have 5 years experience of DSP for telecommunications and great framework (soft & hard) to realise your project. I have my own (developed by me) optimized algorithms of FFT and FEC RS,CRC that are realized in C/C++ code. You can see my portfolio "OFDM PHY layer signal generation" to ensure in my professional skils. I think that FSK is a good choise and I know how to transmit up to the 1.6-3.2kbps by sound channel. Another considerations will be accepted.
I can realise this project by C/C++ for ARM Cortex MCU Embedded systems, but main code of DSP for TX/RX is cross-platform like, so you can easy translate it to another code like C/C++ including Java. TX/RX will be realized by means of embedded ADC/DAC in STM32F4 chip.
Waiting for your response.