Make Noise shared this video that demonstrates using their Maths module as an envelope follower.

Maths is an analog computer designed for musical purposes, including:

• Generate a variety of linear, logarithmic, or exponential triggered or continuous functions
• Integrate an incoming signal
• With no signal applied, generate a variety of linear, logarithmic, or exponential functions
• Add, subtract and OR up to 4 signals
• Generate analog signals from digital information (Gate / Clock)
• Generate digital information (Gate / Clock) from analog signals
• Delay digital (Gate / Clock) information
• Voltage Controlled Envelope or LFO as slow as 25 minutes and as fast as 1khz
• Apply Lag, Slew or Portamento to control voltages
• Change the depth of modulation and modulate backwards!
• Combine up to 4 control signals to create more complex modulations
• Musical Events such as Ramping up or Down in Tempo, on command
• Initiating Musical events upon sensing motion in the system
• Musical note division and / or Flam

Pricing and Availability

The Maths module is available for US $290 from the Make Noise site.