Hello, I'm experiencing problems with external mics on a AM v1.2.0 (sw 1.6.0). They worked well a few months ago, like the SPM0204UD5 (see previous post from Edwin) and Animal sound Labs ME4-em. But now I don't get any recordings with external mic, no reaction at all. I barely used the device so wear is not the cause. Am I overlooking something or is there a possible software or hardware issue? I tried several cables, even directly, but no difference. No problems with the mics neither, they work just fine. One thing puzzles me: I used the mics with the previous sw-version when I tested them the first time, now I have 1.6.0. Could this be related? Is there anyone who is using the same mics with sw 1.6.0? Thanks for thinking with me. All the best, David.
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To see this working, head to your live site.
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No. Can you try again.
Can you email me at alex@openacousticdevices.info so we can investigate the hardware.
I tried 3 and all the same result.
Yes, it's correct that the device makes recordings and switches from internal to external but on the ext mic it stays completely silent.
Those are the headers from the recordings:
Recorded at 02:16:14 01/01/1970 (UTC+2) by AudioMoth 247AA5055F774B30 at medium gain while battery was 3.8V and temperature was 28.5C. Recording stopped due to switch position change.
Recorded at 02:16:00 01/01/1970 (UTC+2) by AudioMoth 247AA5055F774B30 using external microphone at medium gain while battery was 3.8V and temperature was 27.7C. Recording stopped due to microphone change.
Hello Alex, I tried this on 'default' mode and when I plug out the external mic I get the same result as in your video. The light stops blinking for a short time and then blinks again. I get two wav.files, one with silence (mic connected) and one with a recording (mic disconnected). But what do I have to see in the header?
David
Hi David, Can you confirm that if you switch to DEFAULT and plug-in and un-plug the microphone you get a sequence of files that stop and start on each microphone change. The comments in the WAV header will say whether the file is using the external or the internal microphone. Does that recognition happen? Alex
Are there any more options for diagnosis? Or do I have to send in the Audiomoth because obviously something that worked stopped working without any cause. If there is somekind of design flaw it is best that this is solved quickly.
Audiomoth only uses two pins, GND and Output. You need to connect O (output) and + using a resistor of about 4.7 kilo ohms. Connect GND to the sleeve and O to the tip of the 3.5mm connector. Like in the pictures below.
I checked and my unit does exactly the same as in the video from Alex. Is there another test?
"Do both the modified SPM0204UD5 with external circuit and Animal sound Labs ME4-em have the same issue": yes, they both worked before on the AM but now they don't. I tested the mics on another device and no problem there.
"Does the AudioMoth external mic work with any other electret condenser microphones you have?": I don't have any so I don't know.
" Might need the wiring you used to connect these mics up to the 3.5mm jack to diagnose further." This is the schematic from the SPM (I got it from Edwin).
The soldering looks good to me. Do both the modified SPM0204UD5 with external circuit and Animal sound Labs ME4-em have the same issue. Does the AudioMoth external mic work with any other electret condenser microphones you have? Might need the wiring you used to connect these mics up to the 3.5mm jack to diagnose further. For diagnostics, @Alex Rogers has a nice test - here's the video from twitter. When AudioMoth switches between internal and external microphone, you can see it closing the current file and starting a new file each time the microphone is changed, this works best when recording at 192kHz. You can see the files close whenever the LED stops flashing. Does your unit do this?
I just had a look at the jackplug I can see it should not make a diffrence if one uses a 2-conductor (mono) 3-conductor (stereo) or four concductor jackplug. There are two contacts on ring 2, pin 4 connects to GND which makes the audio circuit switch o external microphone. The internal micropone seems to work for David, the external does not, but does the internal mic actually switch off? Maybe you could try and measure if there is a small DC voltage (like 3V) on the microphone signal pins (2 and 5). The voltage should (also?) be present when the microphone jack is in place. If there is no voltage there might be a short in the mic, but as the mic seems to work on an other device it cold ly deeper in the audiomoth.
The picures below com from the applicationnnote and datasheet. I added some lines to explain the pin-connections.
Could you upload a picture of the AudioMoth front face showing the socket connector?
Hello, same result so something else is wrong and the AM device is probably the cause. But the device works fine with the internal mic. Visually there is nothing wrong on the jack plug connection. Like i said, this audiomoth is barely used and only inside. Is there a way to do somekind of diagnostic check?
David
Hi David,
It might be worth re-flashing firmware 1.6.0 again, however, when you do it make sure the batteries are removed during the flash process? The device will need a power cycle after re-flash too so make sure the USB is disconnected before putting the batteries back in.
Let us know if this solves the issue.
Andy