New detector set-up (1 Viewer)

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My new "bat detector" this year, mostly cobbled together from old kit around the house, the dodotronic has brought it all together nicely...

*A dodotronic ultramic 384 Evo
*Parabolic reflector from www.parabolicmicrophone.co.uk
*Android tablet running bat recorder app, and handlebar mount
*Various cables, otg cable,
*Bluetooth headphones
(*Plus zoom h2n and external mic pointing into reflector for bird song.)

The zoom and regular mic really amplifies bird song, especially with headphones. I can hear birds that don't even register with my ears.

Similarly, the ultrasonic mic pointing into the parabolic reflector detects bats that don't even register with my previous bat recorder (Ciel 401).

What is less easy to test, is how much the bat detector set up relies on the parabolic reflector, as comparing requires dismantling the set up, by which time the bat has gone. However, with a set of keys jangling, there was a significant improvement with the reflector.

 

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And a typical output, Soprano Pipistrelle, and feeding buzzes.
There is a noticeable band of noise along ~35khz, mostly tuned out of this sonogram, but noticeable on fainter recordings.

 

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Took the tablet and ultrasonic mic into nearby woods that are known for Barbastelle, and had 3 very brief, fairly distant passes amongst the Common and Soprano Pipistrelles.
The back garden has a Serotine each evening which is cool.

Only downside I'm getting, is the bat recorder app stops every 5 minutes or so. Not a big deal to stop and start the scanning again, but a minor niggle.

I'm in a conundrum as the android devices are small, easy to use, great battery.. but with this bug.
A Linux or Windows laptop wouldn't have the bug, but would be cumbersome, heavier, and probably less battery life.

(,On this occasion, the Chromebook fails on all fronts! Recognises the mic, but I can't get any apps, or the Linux container to see it)

 

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Update: dodotronic identified the bug causing the system to crash every few minutes. They were very quick at fixing my mic, and no crashes experienced since it has been returned. ( No bats either as we are in depths of winter now)

 

[MiddleRiver]

Very cool stuff! Thx.

 

[pppppvvvv]

This is working very well now... just tablet and ultramic for the time being!
The dodotronic on gain 3 (out of 4)

Bat recorder app:
heterodyne range 28khz to 198khz
trigger frequency 38khz to 198khz
trigger threshold -15db
app gain ~1.1
Triggering ON
output Frequency division

walking around, it is only triggering the recording mode on bats. Very few false triggers.
I suspect I'll hear Noctules, but won't automatically trigger. May also need a rethink on Leisler's, Serotine, and Barbastelle, but any tweaking to lower frequencies will be at the expense of more false triggers. Hopefully these species will emit enough signal in the high 30's to trigger automatically.

 

[KC Foggin]

It must be great being so technically talented to make something like this. Good for you!

 

[pppppvvvv]

It must be great being so technically talented to make something like this. Good for you!

To be clear, I only bought the items , and configured the app to work as best it can.
The bat recorder app is really good.

 

[pppppvvvv]

Settled for this set up now. Just leave the tablet in the bag, auto-triggering bats as they pass.
This way I'm not distracted by the spectogram, so actually get to see a few bats.
I get a fair share of false alarms, but the triggering threshold avoids most of the unwanted noises.
Resulting spectograms are pretty sharp too.

The plan now is not to touch the settings again until next winter!