Advice: small recorder needed for study on African leopards and lions

K

Kasim21

New member
Hi everyone,

I'm interested in attaching a small audio recorder to leopard and lion radiocollars and having them record continuously for 1 month.

Minimum specifications:


1. Would need to store 750 hours on audio and run on a single charge. Ideally, it would have a sampling frequency of 22kHz (but this isn't essential and battery life trumps sampling frequency).

2. Combined recorder and battery weight < 100 grams

3. Recorder and battery price < $200

Does anyone know of any recorders that fit the bill straight out of the box, or that could be modified by a newbie?

Complete newbie here and internet signal isn't great out in the African bush; so thanks in advance for your help.

Kas
 
Hi Kas, Ball park calc for one channel at 22kHz (16bits?) is about 6.5H per G so, 120G of storage? There are 128G SDC cards I am sure but might be out of budget! If it can encode straight to (crapish!) MP3 better by an order or so.

But you main problem I think will be power. That weight limit will not allow much battery capacity. Can you arrange for a solar "top up"?

Desert us not but there are some ex BBC guys at Sound On Sound | Recording Techniques | Audio Technology | Music Production | Computer Music | Video Media and they will surely have some wildlife recordist contacts.

Dave.
 
Hi Dave,

Great - thanks for the information.

I will head on over to SOS and post a message.

Yup, power is the main limitation right now. A previous study on chipmunks used a spy microphone (TS-Market: Professional miniature digital audio recorder Edic-mini Tiny B47) for their project which would also work here if there was a way to change the power input to something which would last 1 month. Solar would be a good option in the absence of a big enough battery - my only concern is robustness. The more components on the collar then the more that can go belly up.

Maybe, I'll post something in the collaboration forum to see if there is anyone around who could help to design something.

Cheers again,

Kas
 
That Edic is re chargeable via a USB port? It would seem fairly simple to connect just the power wires from a USB cable and wire them to a suitable solar pack (insert diode) The solar unit would need to deliver some 1 or two volts more than battery voltage (which isn't given) Then, in THAT sun you would probably need some overvoltage protection, zeners. Some messing about on the bench required.

Once right, snot it all up in silicone. There are some top electronics bods at SoS as well.

Dave.
 
Ah, it's getting more complicated by the minute, but good to know it could work in theory.

Time to recruit an electronics bod I think.

Cheers again,

Kas
 
I'd think finding a USB player that has a cheap built-in microphone and 128GB storage would be the easier part, but how long that MP3 device can actually record whether as the result of a file size limit or drained power would be the first questions. There might not be something readily available to record *continuously* for that duration. Now, some video cameras can record indefinitely and accept larger cards, but the size, weight, and power requirements balloon exponentially. Power and weight are definitely the enemies here since finding the perfect solution off the shelf is likely going to bump into one or both of those hurtles.

I would think the issue is that no one really needs a voice recorder that will record and sort files on its own for a month straight (?), which only leaves adopting a video recording technology. Hope for your sake I'm wrong! :)
 
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