Note on the pdf document showing the thermal MAF sensor output.

The sensor output voltage vs actual mass air flow is nonlinear and not a simple function.  It as a complex polynomial and can only be reasonably dealt with by a lookup table using a uC as the controller.

This effectively makes a simple analog-555 approach impossible.
Craig Taylor


Unfortunately I have to agree but we have come up with a custom $5 555 that solves the problem. It consist of an A to D followed with a look up table followed by a PWM generator all for $2.50 less programming and shipping:)

Paul Lamar