I got a new Raspberry Pi v4 and the official touchscreen. The aim of this is to be able to run FLdigi and WSJT-X1 in a portable setup. Also to stop FLdigi getting hopelessly confused on my main PC – with two sound cards already adding a third sound card as interface for the radio meant portaudio, whatever that is, gets hopelessly confused on Windows and loses touch with the hardware intermittently.
Setting it up was surprisingly painless – blow a new 16Gb SD card with Raspbian, connect screen to the 5V and 0V on the GPIO and the ribbon cable to DSI. Normally you then have to remember to add the empty file ssh to the boot partition with the PC so you can talk to the damn thing, and perhaps wrangle the wireless config if the Pi doesn’t have Ethernet.
With the touchscreen I didn’t need all that. Although I started it up on ethernet, the onboard Bluetooth meant I could connect a Bluetooth keyboard using just the touchscreen, and then set up the wifi in the usual way. The touchscreen needs a reasonably firm press, this is no responsive smartphone screen, and being so small it is sometimes hard to get the right target, even with a conductive stylus, particularly as I set the font size a little smaller to use the screen area more. Continue reading “Raspberry Pi 4 with touchscreen and FLdigi”
There’s a welcome reduction in aircraft during the coronavirus pandemic, which means our soundscapes aren’t scarred by the rumble of jets. I listened to the lovely soundscape unfold, with an extract from the early part of the chorus which is more sparse, the later part which is denser and richer in sound.
It was a lovely expedition to a local nature reserve, and I am intrigued to sample other nearby soundscapes with less human-induced noise. The gorge helps shield the valley from noise, it will be interesting to see if this works on the Somerset Levels as well, which don’t have the protection of lots of limestone rock.
I joined with Locusonus and the Reveil project to broadcast birdsong from near my garden for International Dawn Chorus Day. Due to the coronavirus pandemic the choice of locations was limited. It’s good to appreciate one’s local birds, however, this blackbird sang well after he’d settled down from whatever fright woke him up at the start.
These mics aren’t the finest – basically cheap Chinese electrets because they’ll be left out in all weathers. IDCD was a still dry day, and the birds could give of their best, with human noise lower than usual. The recording extract starts at at about a quarter to six BST.
International Dawn Chorus Day 2020 is somewhat overshadowed by the coronavirus pandemic for its human listeners. The birds probably appreciate getting some peace! The Wildlife Sound Recording Society was after getting a live broadcast of this from as many members as possible. They proposed two methods of live broadcast, their preferred option using Mixlr and a more gonzo alternative using locusonus.
Mixlr seems all about tablets and mobile phones. If a project’s got a mobile phone in it I’m not interested. I loathe smartphones – jack of all trades and master of none. They don’t do stereo1, FFS… Mixlr is Cloud. I don’t do Cloud, particularly if it comes with a subscription. It’s bad enough when Cloud goes AWOL and you’ve put effort into the platform for free. Pay for the privilege? Nope.
So I passed on that and went to locusonus, who are doing this under the Reveil soundcamp moniker. Locusonus is funded by the French State, bless their arty dirigisme – just look at their publications. And sponsors
So arty! So French!
Reminds me of reading about musique concrete as a kid in the 1970s, IRCAM and all that, while I was piddling about with a hand-me-down Stellavox tape recorder. Mad, but inspirational. I’ll hitch a ride on French exceptionalism.
I’m lucky in that way back when I bought a Cirrus Logic sound card for a Raspberry Pi. Or perhaps unlucky in another way – I never found a good use for it till now, as the software drivers were a whole load of hurt. By the time they got incorporated into Raspbian, the card was end-of-lifed so you can’t buy them any more. That’s Linux for you. Free as in beer but slow to integrate hardware. If you are doing this from scratch, either use a cheap audio adapter with mono audio or something like the Behringer UCA202 USB audio card – stereo line in and works great with the Pi, right out of the box.
Despite fiddling with the CirrusLogic on and off I came to the conclusion a timed bird sound recorder is better done with a Dribox and a real audio recorder and a timer. However, a Pi and the CL card is perfect for locusonus. Perfect enough, indeed, that downloading the relevant Pi SD card image, blowing it onto a SD card and firing it up on ethernet gave me an instant win2, using a set of OKMII binaural mics into the line in port with the bias enabled. I was able to hear myself, albeit at a low level, but the locusonus software lets you ram the Cirrus programmable gain amp up to +30dB and max digital gain. Sure, it’s noisy, but showed the principle.
The Logitech C920 is a lovely little webcam, and having the MP4 conversion on the onboard processor means you can use it with gutless hardware. I got mine as a cast-off from Jason at Wildlife Gadgetman and wanted to use it for video-conferencing, what with the coronavirus lockdown and all that.
Trouble is the damn thing is short-sighted. It seems to be a common problem with the C920, and the autofocus is ratty. Sometimes it would work, sometimes not.
I am short-sighted too, so a temporary fix to get it to focus on distant objects is to Sellotape one lens my glasses over the front, but it’s not a good look. AF was still ratty. Poor distant focus is a common complaint with the C920. This fellow shows you how to take it to bits
but unlike him, my fault was the little piece of metal had become loose and was fouling the movement of the lens.
the squarish metal washer with three notches had come adrift.
Extracting the washer from the lens, using the notches to pass the castellations on the lens mount let me isolate it
I did consider leaving it off
but figured I’d get flare from reflections from the plastic cover in front so I used thick superglue, carefully to avoid getting it on the lens. Four dabs at the corners sorted it.
Job done, sorted. This doesn’t seem the only way for these cameras to misbehave on focus, and unfortunately you can’t see the errant washer because of the baffle on the plastic cover. But you have to take it to bits if your problem is the focus is off as the one in the video. There’s a neater way to do the glasses thing with an eyepiece adapter lens as in this video, which doesn’t entail taking it to pieces, but that wasn’t the problem for me.
At noon and 3pm a bell in rung in the Chalice Well Gardens, Glastonbury to invoke a minute’s silence for reflection. A wren breaks the silence, and the bell is sounded again at the end of the minute.
The bell was the old school bell, the school buildings were cleared in the 1970s which opened up the bottom of the gardens a lot.
Fabulous reverb in Winchester Great Hall with its iconic Round Table, one of the many seats of King Arthur in the British Isles. There are probably as many true Arthurian residences across the UK as there are oldest pubs in the land 😉
Some visitors wandered over to the door on the left which leads to Queen Eleanor’s Garden and the large door closes with a resounding clang.
The huge imposing structure of Winchester Cathedral has a fantastic long reverberation time
and some remarkable low-frequency sounds. There is some research suggesting very low frequencies induce a sense of awe, quite appropriate for a cathedral 😉
Winter is coming, and that means that millions of starlings are on the move, from the deep cold of Continental Europe to the relative mildness of Britain’s winters. We are surrounded by the sea, which buffers the temperatures reducing the cold in the depths of winter. They join our resident starlings to roughly double the population in winter, according the the RSPB.
A starling is nothing that special individually, but in winter they roost communally in reedbeds1 these days. They group together in massive billowing clouds called murmurations2, this is thought to be trying to confuse birds of prey, who can’t home in on individual birds.
The unquiet sound of massed starlings
Once they’ve settled in for a while a massive racket starts to built up, this is a binaural recording best on headphones. The slight dread at 4:30 is when a bird of prey came along, it silenced the starlings closest to me but most of the roost was still rapping away to each other.
I managed to get myself to within fifty yards of one of their roosts on Ham Wall, in the Avalon Marshes complex of nature reserves, sited on only peat extractions. Although the starlings tend to roost somewhere on the reserves, which site they favour varies from day to day. When you’re that close to the roost, you get to hear the damnedest noise from these guys. A starling roost is not a peaceful place – they charge around low in the reedbeds, and as the day gave way to twilight I saw a bird of prey strafe in low over the water, though I couldn’t make out whether it won its supper for the night.
It was a slight challenge to stand my ground as I was buzzed by wave upon wave of birds incoming on all points very low. They didn’t go for me, although The Birds3 movie did come to mind.
Some tips if you are going to visit a starling roost
Choose a still day, the starlings take more time about their murmurations if they don’t have to fight the wind or rain
Go early in the season – November or December. The season persists often through to March, but starling shit is a pretty noxious smell. The hum builds up to an acrid stench as time passes
For the same reason, keep your mouth closed if you look up at phalanxes of starlings passing overhead 😉
Go on a weekday – fewer people and dogs with all that goes with that…
Avalon Marshes has a Starling Hotline 07866 554142 that tells you where the birds roosted last night. That doesn’t tell you where they will be tonight, but it lifts the odds. It’s a dead cert if you fancy the early morning sight when they leave, however.
Take a torch. It’s very dark when the birds pack it in, and the cold comes as the sun goes down.
In the early parts of the 20th century when the starling population was much higher and we hadn’t killed off most of the insect population they had massive urban roosts in London. ↩
You can find a roost near to you on the Starlings in the UK site to see murmurations for yourself ↩
