I recently came across the Retroactive Pedals Dot Chaser. According to the website
, it's a PT2399 based envelope optical modulator. 'Lag' control manipulates the single repeat delay time, with a full wet/dry 'mix' knob. 'Warp' controls the amount of modulation from the LDR network, also equipped with a master 'Vol' pot. More intense or drastic modulation can be audibly heard when engaging the 'more' switch.
Guitar demo here on YouTube.
Does anyone know of a DIY pedal that comes close to this one?