Hi all,

I have an Bela>Accelerometer-related enquiry.

I'm using the LilyPad (Sparkfun) ADXL335. It is encased in conformal coating, insulating tape, and many layers of PlastiDip rubber sealant.

It's wired to the Bela via a 2m, 5-core, self-built cable, with 5 individual insulated wires encased in a 2m metal cable sheath, which is in turn wrapped in insulating tape.

None of the wires connected to the Bela are loose or faulty; they're all perfectly conductive and firmly connected.

The accelerometer is wired up exactly as per your example diagram. Up until recently, it has been responding perfectly well to all types of movement.

On my most recent tests, however, I've found two very strange things are happening on Axis 1 (wired into [dac~ 27], when I observe it through the oscilloscope.

First of all, it's oscillating a little more widely than the other axes (the others oscillate pretty imperceptibly, but Axis 1 oscillates continuously within a range of about 0.2).

Secondly - it doesn't respond when the accelerometer is moved, holding the accelerometer in my hand. HOWEVER - and this is the really strange thing - it responds dramatically to the smallest movements of the shoes on my feet, at least a meter away.

My feet/shoes are not making contact with the accelerometer (or anything conductive) in any way. The accelerometer remains totally still in my hand, wrapped in insulation. Its connecting cable is also held totally still; so is the Bela, my computer, and everything else in the room.

I've narrowed it down to the rubber sole in particular - and in particular when I'm actually wearing it - that influences the reading so dramatically, though only when it's at a distance between 1-2m away from the accelerometer.

More mysteriously, Axis 1 only responds to accelerometer movements if it is aggressively 'jolted', but its response to my shoe is dramatic, and perfectly aligned with its smallest movements (across the axis' entire range).

I've contacted Sparkfun for support, but they suggested that the accelerometer is simply broken, which doesn't seem to answer the question at all. Axis 1 is still very responsive - it's just responsive to my shoe, instead of being responsive to the accelerometer's own movement!

I'm at my wits end - I wouldn't have brought this to the Bela forum, but I know it's full of a lot of smart people, and that maybe the Bela has something to do with this. In researching accelerometers, I can't find anything that would suggest they would respond so strongly to a nearby rubber object.

Can you help? Thank you!