Rockbox Technical Forums

Support and General Use => Recording => Topic started by: Simon1973 on May 24, 2007, 02:10:45 AM

Title: Autonomous Recording of Desert Birds
Post by: Simon1973 on May 24, 2007, 02:10:45 AM
Hi,

I am new to this forum and I am also no programmer. Apologies therefore, if I am covering some old ground.  At this stage, I am not looking for any technical detail but would like to seek some advice.

I am looking at options for using a hard drive recorder to do autonomous recordings of desert birds at night. Systems would have to be in the field for perhaps a few months, so I need some particular features, mostly to minimise the sheer quantity of data that would need to be analysed. From what I have read, rockbox appears to already have some useful features but I am not sure how difficult it would be to incorporate any others.

I would like to 1. limit recording to particular times of the day; 2. trigger recording on receipt of signal (rather like VOR); 3. limit recordings to fragments of say, 1 minute following the trigger; and 4. begin recording with a buffer of about 3s.

This will also depend to some extent on the MP3 player, which will have to have a line-in for a microphone. I would be extremely grateful if anyone could give me some initial advice about which players would be best (probably an Iriver device) and whether any or all of the above functions exist within Rockbox. If not, then how much effort would it take to develop them?

Kind regards,

Simon.
Title: Re: Autonomous Recording of Desert Birds
Post by: Domonoky on May 24, 2007, 07:33:54 AM
Hi,

i would recommend a iriver H120/140 or H320/340, they have very good recording capabilitys and the h120 even has optical line in/out, but these players are hard to get.
Another option would be an iAudio X5, i dont know how good the other players can record.

And to the Features:
i think Rockbox already supports most of the features you need, i dont know the recording options too much ( read the manual) but there are many options to configure the triggering of beginnig and ending a recording.

hope i could help.
Title: Re: Autonomous Recording of Desert Birds
Post by: bluebrother on May 24, 2007, 10:05:31 AM
i would recommend a iriver H120/140 or H320/340, they have very good recording capabilitys and the h120 even has optical line in/out, but these players are hard to get.


The h100 series doesn't have a real time clock -- this might be needed in your case. There's a mod around to add a rtc chip to that players, so if you aren't afraid of soldering the h100 series might be the best suited. The h300 series already has a real time clock.
Title: Re: Autonomous Recording of Desert Birds
Post by: Simon1973 on May 24, 2007, 04:36:33 PM
Thanks so much. I forgot to mention the need for a clock...it was very observant to notice. As you suggest, the H300 may be the best option. The triggering mechanism in Rockbox looks pretty good but I would have to experiment with relatively low audibility sounds. The only other problem is perhaps timed recording for night time, but I reckon that would be easiest by using a light dependent resistor to cancel any incoming signal during the day.
Title: Re: Autonomous Recording of Desert Birds
Post by: bluebrother on May 24, 2007, 04:43:29 PM
You might also look into the Recording Enhancement Pack which includes (afaik) the recording timer. This is a feature that is planned for Rockbox itself, but the current implementation has several flaws (from the programming perspective) and doesn't adjust nicely to other players.

If you want to control the player using external hardware you might also want to look into the remote connection -- it's a simple resistor network that generates the buttons, and it's quite easy to interface this with other hardware (I'm planning to build up an external IR remote receiver for my h120 -- still waiting for time to arrive for actually doing it, but my first tests at interfacing worked nicely)
Title: Re: Autonomous Recording of Desert Birds
Post by: Davide-NYC on May 28, 2007, 10:19:08 AM
Get an iRiver H1xx and put a clock in it. It works like a charm. No patching necessary, but you will have to compile the build yourself.

See here: http://www.rockbox.org/twiki/bin/view/Main/RTCModH1x0
Title: Re: Autonomous Recording of Desert Birds
Post by: cbr12 on May 30, 2007, 02:08:29 PM
I have used the Iriver H320 for autonomous recording of owls. These units are probably your best bet as far as jukeboxes are concerned. About the longest I could get the recorders to last was 16 days, then I would download the data and start them up again. I recorded in Mono and used the Wavpack format to save on hard drive space. I did not use the trigger function, instead I used the countdown timer patch and set each unit to record every night from 6 pm to 6 am. With a little work it may be possible to use this countdown timer and the trigger function simultaneously. That would save you tremendously on hard drive space. Another benefit of the H320 is that each file has a time stamp. If you want a larger hard drive buy the H340 and replace the drive with a 60 or 80 GB hard drive. This will give you more time before needing to download your data. You will probably need to get a used Iriver since this model has been discontinued and they can be difficult to find. Try Ebay.

Good Luck, Cameron