EWI Bite Sensor Mod

20 March 2019

I’ve owned an EWI-USB for a few years and I haven’t been able to get used to the bite sensor – for me it feels like I have to bite too hard to make it work. I use bite for pitchbend so I can “scoop” up to a note. My Roland Aerophone has a completely different mechanism and it performs this function reasonably well (see my previous post on the subject).

I had cause to remove my EWI mouthpiece the other day and thought I’d take the opportunity to look at making a different mechanism. What I came up with is this:

It’s a switch which I push with my lower lip (with my teeth behind my lip). I removed the capacitive sensor fingers inside the mouthpiece, and wired the switch so that when pushed it adds a 2.2nF capacitor across the connections. The capacitor is inside the EWI body. I tried a range of capacitors, and found the 2.2nF to be OK.

The 3D-printed switch housing just slides over the silicone mouthpiece and the distance of the switch from the tip of the mouthpiece and be adjusted by inserting or removing spacers from between the housing and the EWI body.

The EWI settings I’m using are:

  • Bite controller – Pitchbend down
  • Bite sensitivity – about 12 (this is dependent on the user and the synth settings)

So why did I go for an on/off switch, rather than a progressive device? Well, my Aerophone bite sensor is progressive, but in practice it operates like an on/off switch because the progressive zone is so small, and its operation is acceptable to me. Plus, making a switch arrangement was much easier!

Early days yet – we’ll see how it goes….