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AudioMothDev Input Jack Alternative?

I am placing the AMDev board inside a 2 inch waterproof enclosure and the input jack is too close to the side and cannot insert the TRS jack (see photos). How can I connect signal inputs to the board and bypass the physical jack?

15 comments

15 Comments

Alex Rogers

Sep 22

Another option is to use a standard AudioMoth and de-solder the battery holder. Then the 3.5mm socket is on the short side.

Mike Bennett

Sep 22

Replying to

Figure 5 shows signal from pad #10 on your diagram. Are you sure pad #4 is signal?

Alex Rogers

Sep 23

Replying to

It means that the jack detect pad must be connected to ground.

Alex Rogers

Sep 23

Replying to

The application note describes the connections on the socket used on AudioMoth 1.2.0. This is different to the socket used on AudioMoth Dev 1.0.1 as that original is no longer manufactured. AudioMoth Dev 1.0.0 uses the same socket as AudioMoth 1.2.0.

The socket on the AudioMoth Dev 1.0.1 is a CUI Devices SJ2-35894D-SMT-TR socket. It has a different footprint and different connections compared to the one described in the application note.

Pin 1 is ground (normally connected to the sleeve of the 3.5mm plug)

Pin 2 is signal (normally connected to the tip of the 3.5mm plug)

Pin 4 is jack detect (normally connected to ring 2 of the 3.5mm plug).

Normally, when you plug in a 3.5mm TRS plug (without a physical ring 2) pin 4 gets connected to pin 1 through the sleeve of the plug. You are replacing that process by connecting a wire directly between pin 1 and pin 4.

Then you provide the signal to pin 2.

Edited

Alex Rogers

Sep 13

Any soldering iron intended for electronics will work for soldering to the upper surface of the existing solder tags. The reflow section is really about the temperature profile when the whole device goes through an oven.

Mike Bennett

Sep 13

Replying to

I measured the tip of my Hakko FX 888 and it's only 150 degrees F. I don't think that's enough, do you?

Alex Rogers

Sep 13

Replying to

Most soldering irons will be at about 350C in use. Any less and it will struggle to melt the solder.

Mike Bennett

Sep 13

Replying to

Correct. Time to get a new one!

Alex Rogers

Sep 13

The AudioMoth Dev 1.0.1 uses a CUI Devices SJ2-35894D-SMT-TR socket:

https://www.sameskydevices.com/product/resource/sj2-3589x-smt.pdf https://www.digikey.co.uk/en/products/detail/cui-devices/SJ2-35894D-SMT-TR/6619567 This is the same socket used on the AudioMoth USB Microphone 1.0.1. It is different to the socket on the 1.0.0 versions of both boards as the original is no longer manufactured. To bypass the actual socket you can make connections directly to the solder pads as below. The 'Signal' is normally connected to the tip of the 3.5mm plug, and the 'GND' is connected to the sleeve. The 'Jack Detect' should be connected directly to GND to tell the AudioMoth Dev that a plug has been inserted into the socket. If you disconnect the 'Jack Detect' wire the AudioMoth will use the internal microphone and ignore the signal from the 3.5mm socket.

Edited

Mike Bennett

Sep 13

Replying to

Thanks Alex. Looking at the CUI sheet it has a section about soldering reflow and a graph on temps. What soldering iron would you recommend I get to have the temps necessary for re-soldering?

Mike Bennett

Sep 22

Replying to

It would be great for the next hardware version to include a JST connector mounted just above the jack so it's easier to connect and disconnect. Is there a JST connector made that could be solder mounted to the top of the jack? If so what is the part number and where to get?