from what I'm hearing in the Camera sound, there is no envelope filter. to me it sounds like a narrow band noise, so you're pretty spot on: a white noise generator through a filter (like the systech harmonic energizer) should give this type of sound, but you should change the cutoff frequency with every note...
on the other hand, the rainger pedal seems "quite simple", you'd need a white noise generator ( paul stevenson has one on his great website, of course:
http://www.paulinthelab.com/2012/07/white-noise-generator-stripboard.html ), a mixer stage to blend you're incoming signal, some kind of dirt section (before or after mixing, I don't know...) and an envelope filter.