Raspbery Pi application

[Russell]

From the outset I will say I have no code writing experience and know even less about the Raspberry Pi but I think it might work for a requirement I have.

Basically it is for a disc recorder to take in an analogue audio signal, output a headphone feed and be able to record the audio when required, preferably starting some seconds before the record button is pressed and to continue until the button is pressed again.  It also needs the ability to be able to export the recorded files in MP3 to a PC for analysis.  Battery powered as well for recording in the field.

Is this possible, is it commercially available etc etc??

Thanks

[Greenbank]

Definitely possible.

You'd need a USB audio dongle because:
a) the RPi's audio output isn't very good quality (not that this really matters for headphones)
b) the RPi has no audio input

You'll also need a button to wire up to some of the GPIO pins to act as the record button, an LED to let you know the recording state would be nice to have too.

Battery power is not a problem, just use a USB power pack.

preferably starting some seconds before the record button is pressed and to continue until the button is pressed again.

(My emphasis). I take it that's the reason why you can't just use an existing dictaphone or other digital recorder. Again it's perfectly possible for the Pi to be buffering the last n seconds of audio just in case the record button is pressed.

Post processing into mp3 is easy.

So, it's possible but I doubt it's commercially available. It would take someone with the right skills (and bits) less than a day to knock up a prototype I suppose.

[fuaran]

Maybe easier to use a phone or tablet instead? Would give you a battery and screen built in. Plenty of apps available for recording audio.
Easy to connect a microphone and headphones (look for a TRRS adapter). Or a USB microphone may be better quality.

[Russell]

Apologies for the delay in replying but we were in Devon visiting Mum this weekend.

Son has a Pi that is gathering dust and I have a 10000mAh battery.  Found a USB audio dongle on Amazon for not much more than a fiver so it looks like we could have the hardware to make a start.  No idea where to begin but Son says he will give it some thought.  Any pointers would be appreciated!

Phone/tablet recording sounds like a plan except that a search reveals that few apps offer headphone monitoring and none so far offer headphone monitoring unless it is recording mode which is a non starter as there is no point in this exercise unless one can hear the sounds to start with.

Thanks for the comments.

R

[David Martin]

Try Edublocks and see what they have as a set of dragndrop options.

[fuaran]

Is it for a bat detector? I have just been trying this sort of thing.
This Bat Recorder app lets you record, with headphone monitoring. Plus can display a spectrogram etc. https://play.google.com/store/apps/details?id=com.digitalbiology.audio
It can work with any sort of microphone input, not necessarily ultrasonic.

Though there should be other simpler audio recorder apps, if you don't need all those features.

I am using one of these cables, which gives you connections for a microphone and headphones. Depends on what sort of microphone you are using, and whether it is powered, the cable needs to have the correct attenuation. https://www.conversorproducts.com/microphone-headset-adapter-cable-for-ios-devices-battery.html

[David Martin]

I use that app - very nice and does the business with my ultramic 250k.

Currently working on the audiomoths to automatically process the data. Looks a bit flaky when the batteries start to go.

[Russell]

Is it for a bat detector?

Yes it is.  I have a Baton which is basically a divide by 10 device.