(simple) problem changing pitch for makenote

I am trying to build a sequencer type device, the basic idea is that a metro object sends pulses through a pitch selector (I'm using a live.numbox, it could just as easily be a number object, a slider, etc.), which then goes to a makenote.

My problem is, when I change the pitch in the note selector (by dragging it with a mouse etc.), it outputs a huge blurt of notes every time the value is changed. What I want is for the makenote to not receive the changed pitch until the next metronome click.

I've tried setting up something with a gate, with the numbox feeding into the right inlet of the gate and the metro bang going into the left outlet of the gate, but gate doesn't work quite like that -- it seems to need a steady "on" (via a toggle etc.) in the left inlet.

Is there a way to get around this, to require an explicit bang (from the metro) before the new pitch value gets sent to makenote?