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Date: Sun, 09 Mar 2014 01:47:26 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Microphone via WLAN (WiFi) ?
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Hi all,

Thanks for all the comments and ideas.

Well, the low power consumption is essential. I would have no problem to 
exchange an accumulator each 2 weeks but not 2 times a day ;-) Also the 
described systems appear to complex to me (and to other users).
At home i have a standard USB WLAN adapter and i can measure the power 
consumtion tomorrow but i guess it is less than 50 mA. Also, if possible 
i would like to avoid using additional software like VLC and so on. I 
need the PC for several SpecLab instances and a few VAC instances. It 
would become complex then...

What about that WLAN camera? It consists out of two parts, ok, but the 
/p part is very compact, has a WLAN output and a microphone. This 
appears to be very close to what i'm searching. So it cannot be a 
miracle or utopic. See 
http://www.amazon.de/Kamera-%C3%9Cberwachungskamera-Empf%C3%A4nger-Zubeh%C3%B6r-Wireless/dp/B004AZL6AE/ref=pd_cp_ce_2 

OK, it needs to be connected to the soundcard by hardware but maybe that 
is even better or more flexible, at least it is not to much effort and 
does not consume additional CPU load...

Any other ideas? Would you think it is worth a try, i.e. to buy it?

73, Stefan/DK7FC


Am 09.03.2014 00:47, schrieb Tobias DG3LV:
> Hi Stefan  !
>
> 10 mA at 5 Volts will not be enough. You may get analog(!) audio 
> transmission sets for 2G4 or 5G8, but they do not use WLAN.
>
> As Wolf has stated, there will be a lot of software involved in all of 
> such a system you want to use.
>
> Maybe this could work w/o software development:
>
> Transmitter site using a RaspberryPi equipped with ext. Soundcard and 
> WLAN. Software "VLC"/Linux for "audio streaming"(Server).
> Receiver site using standard (WLAN-)Windows PC and software 
> "VLC"/Windows for streaming client.
>
> Setup both VLC's to uncompressed audio. That should deliver 16 Bit 
> Stereo audio (max. 96dB SNR) at 44.1 or 48 kS/sec.
>
> A RaspberryPi consumes abt. 3 Watt + soundcard + WLAN. Would that fit 
> your requirements ?
>
> 73 de dg3lv tobias
>
> Am 08.03.2014 15:08, schrieb Stefan Schäfer:
>> Hi all,
>>
>> Again i spent some time to find a module which allows to transfer a
>> mircophone input signal via WLAN to the PC. Without success...
>>
>> To make things clear:
>>
>> The system has to consist of to parts:
>>
>> 1: The first one is battery supplied and has a microphone input (like a
>> cheap external USB soundcard) and a WLAN output, using an external
>> antenna and SMA plug. I.e.: Input: 3.5mm microphone jack. Output: SMA
>> WLAN antenna connector.
>> 2: The second part is connected to the PC and is a WLAN receiver that
>> appears as a normal external USB soundcard and allows to receive the
>> audio signal from the first part of the system.
>>
>> The system allows to run a /p receiver for VLF or any other band.
>>
>>
>> An expert could create such a circuit for himselfe but i need to buy
>> something like that, if it is available. But all i can find in the web
>> is the opposite way, i.e. people who want to transfer their sound from
>> the PC to a /p loudspeaker or headphone, argh...  Or, a big device which
>> includes a real big microphone (dynamic range ???). These are expensive
>> systems.
>>
>> However, external soundcards are cheap and WLAN modules are cheap too.
>>
>> So, isn't there such a device for a few EUR in the web, these days? It
>> has to have a dynamic range of  at least 100 dB, like the 2 EUR external
>> soundcards at amazon do (with some luck).
>>
>> Any help is much apprechiated :-)
>>
>> 73, Stefan/DK7FC
>>
>>
>