I received the vibration sensor and the MCU boards for the challenge and I am starting to evaluate an appropriate method of sensor attachment for my experiments.

 

The included instruction manual from Tokin has quite a bit more detail than the Kemet datasheet that is linked from Element14.   The sensor housing is quite small (8.4 x 11.4 x 2.9 mm).  It comes attached to a 3 m shielded cable that is about 2 mm in diameter and is terminated in a tiny SHR-03V-S-BSHR-03V-S-B female connector that has contacts on 1 mm pitch.   I had hoped that the manual would provide a circuit diagram for the integrated amplifier but it doesn't.  I haven't been able to find anything about this sensor on the Tokin website and I can't find this instruction manual using Google.

 

My first impression is that the sensor assembly seems very fragile and that conclusion is supported by the handling warnings in the instruction manual.

 

I'm going to try mounting the sensor on a desktop microphone stand that has a weighted 2.5 lb base.  I've 3D printed a couple of pieces to facilitate that.  The first is a cap that attaches to the top of the threaded riser and the second is a baseplate that holds the sensor and attaches to the cap.  I decided on a two piece construction because it appears that the preferred mounting method for the sensor is using adhesive and there is concern about putting any steady pressure on the sensor body (I had initially planned on using a clamp).  So, I'm going to attach the sensor to the baseplate with adhesive and the baseplate also will provide strain relief for the cable where it exits the sensor housing as that seems like the weak point in the assembly.  If I decide to mount the sensor somewhere else, I just need to print an adapter for the baseplate and can leave the sensor semi-permanently attached to the baseplate.

 

The connector at the end of the cable looks like a mini JST 1.0 mm connector, but I can't find a cable that would interface with it.  The recommended mating connector is a surface mount PCB connector - either SM03B-SRSS-TB (straight) or BM03-SRSS-TB (right angle).  The BM03 is available at Newark for $0.51.  I'll probably make an adapter board to use with Grove cables which I have a lot of.  It will also provide a spot to put an amplifier if I need to add one.  I won't be able to get a connector before next week, so in the meantime I'll work on a program for data collection.

 

 

Links to my other challenge blogs

Person Identification using Footstep Vibration Patterns