coreyr
2051
I’m a big fan of the wireless security gates at big box stores that pickup the RFID security tags. Also ATMs, screens, buttons and electric motors to dispense cash. Power tools. Computer printers and scanners. Xerox machines are great! So many different parts to to take emf readings from.
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You’re right about the substation EM, and the aerial high tension power lines emit the exact same EM field, during the 15 min walk I cannot have the hexagon pointed up even slightly if I want to avoid the stable sound (power line all the way to the substation). I was able to get the more interesting stuff from the concentric circular “things”. Very awkward position, quite the sight. But I was not treating the priezor as an instrument, maybe I should!
Next - small local amusement park
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Thanks. At first I plan to just place the AudioMoth in the back garden near our bird feeding table. The jackdaws and robins and magpies will be loud enough I think. 
When I get more comfortable with how it works I’ll probably talk to the local park rangers about getting permission to leave it overnight in some old quarry shafts and other less suburban places near me like canal banks.
Thank you @disquiet for making me aware of this. I’ve taken the plunge and ordered one and the official enclosure as well.
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If you have any other photos of the smaller clips/clamps being used, it would be so helpful to see. I’ve been struggling with ways to connect a small strangely shaped B&K accelerometer which I connect to branches and flower stems. I have been using hair clips on piezos which works nicely most of the time
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timp
2055
This is all the clamps & clips I use with my contact mics (ruler for scale but you can also see the size of the Trance Audio contact mic element, as that’s the scale & shape I am working with)
I’d suggest you need to go visit a few hardware stores and office supplies, and take the acceleromoter with you to try out some options… eg the blue clamp which are quite light but maintain a strong grip are from an office supply store & used for clamping eg a film script of 120 A4 pages together, same for the very small black clip. The others are from hardware store. I’d imagine attaching to a branch is not so difficult if you can get or make a flat surface. Attaching to a flower stem would be difficult without crushing the stem. In that case maybe velcro is better?
I rarely use the ltitle G Clamp, but eg the big red clamps I used to attach contact mics to long wires strung across my garden (I also tied some string to them, so if I dropped the clamp I don’t have to go searching for it)
re flat surface on branches, I shared a photo I found online of someone using a contact mic on a tree. And they had cut a square of the bark off, so the contact mic was attached directly to the core of the tree and not the bark. If I was going to do that I would take some tree pruning paste with me, as it’s otherwise like leaving an open wound & would be a bummer to revisit years later to find a dead tree.
Ah here it is, from this site: Listening to a Tree
Having said that, there is a wilding pine tree I need to cut down, so maybe I’ll cut into it & attach contact mic this way before I deal to it.
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Good luck with your initial deployments! That was very much my approach at first, since I was reluctant to venture beyond my balcony with such a small, delicate device.
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thanks a million for sharing. Interesting to see that tree image. I was using some very cool phantom powered contact mics on trees and a friend in Ireland suggested using an Ursa Strap to keep them in place
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@timp - Hi, very nice! thanks for sharing.
Are the contact mics Trance’s Acoustic Lenses? (their acoustic guitar pickup)
is it the true stereo or dual mono model?
How does it sound?
Sorry for the many questions
Trying to improove my contact mic set, currently on DIY piezos, no preamp, considering options.
Thanks!
timp
2059
I found email from when I ordered it (2012) and its a Trance Audio Stereo Inducer - I think i got the first one of the new design… But I think of it as dual mono, as each mic element has 6ft cable and any stereo spatial info is 100% dependent on placement and the material its attached to (ie the speed of sound in the medium) (eg speed of sound in Steel, 1% Carbon, hardened = 3,150m/s as opposed to in air 331m/s, so that’s 10x faster arrival time)
I was a big fan of the Barcus Berry Planar Wave contact mic system & it is excellent but the mic element is fragile by comparison to the TA - I broke & replaced maybe 5 or 6 BB mics before I gave up on them. Those are designed for Piano & Harp and are excellent for that purpose, not so much dirty industrial machines and random props 
Only downside to the TA is its powered by 2 x 9V batteries. I did ask if they would mod mine for phantom power & they said they don’t as it impacts people like me who record high sample rate & pitch down 1-2 octaves…
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Excellent, thank you for taking the time!
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I bought a single Trance Inducer around 2010. I don’t know if that’s older or newer design. Still, it’s the best of them (not being able to try an original Frap) that I’ve used
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hi Marc, seeing your post led me investigate the audiomoth but it did not seem to be immediately available so i decided to cobble together something kinda similar.
this is a raspberry pi zero w with a mems microphone (ics-43434) and a pisugar3 battery. with the battery’s scriptable power manager i can schedule the rpi to shutdown and later startup (something raspberry pis aren’t able to do on their own). my plan is to set it up so it wakes up every hour, records one minute of audio file and then shut down. that way, i should be able to let it do its thing overnight without any worries that the battery will run out of power.
i barely understand what i am doing but i am making good progress and will report back once i have this fully functional.
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Nice. Please do. And protect it from the elements.
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kcolf
2065
there’s some nice r-pi autonomous recorder projects out there that might be useful - the solo is good:
also bat pi:
http://www.bat-pi.eu/EN/index-EN.html
my studio built out a recorder using the Sony Spresense development board - using the GPS on the units to sync multiples across long distances and a simple phantom circuit to attach two DPA 4060s for high quality stereo.
The advantage of the sony board was that you program it like an arduino so the process is a lot faster than the full setup of the pi and the battery life was also much longer - pandemic and other stuff got in the way so we never developed it further but happy to chat about it more if its useful to anyone
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last night i was able to get everything working well enough to perform a test run. i put the recorder in a ziplock bag and left it outside from around 23:45 to 06:15. i had it record for 1 minute approximately every 15 minutes. when i checked it this morning, i had 29 recordings and 82% of the battery was remaining.
here is an example recording with default normalization applied in audacity:
the basic setup for the mics followed these instructions:
if anyone is interested in the code to automate the recordings and get the popsugar3 battery manager to stop and start the pi, i am happy to share that too.
monday, i leave for europe (starting in hailuoto, finland) and am excited to hear what sounds i am able to capture there.
@kcolf, thank you for sharing these additional rpi resources. i will check them out.
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We’re spending a couple of days on Rosala island and at Bengtskär light house this weekend (both in the southern archipelago of Finland, in the Baltic Sea). Capturing some wind, waves, rocks, terns, sea gulls, and hopefully some buoys and a staircase at the light house.
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I have a question, besides listening a lot when visiting different places, is there a method of listing potentially interesting places to go and record ? So far I have focused on bodies of water and wildlife but I sometimes feel stuck when at home about where to go to record something new.
muncky
2070
Strongly recommend this book for looking/listening closer to home
https://www.ezekielhonig.com/bumping.php
I owned it for a long time before reading it, but it’s quite incredible for examining / mining the world you’re in.
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timp
2071
Two thoughts on this, first:
Second, an aspect that 100% influences whatever you plan to record outdoors is… the weather. And it is also contains & creates its own complex world of sounds.
Do you know how to research & forecast weather? It is an invaluable lifelong skill and an endless source of fascinating sounds. I documented my process back in 2019 (ie planning field recording based on weather, tides etc rather than happenstance)
https://www.musicofsound.co.nz/blog/forecasting-your-shoot
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