ECA: Ethanol Content Analyzer

Ethanol Content Analyzer for Arduino Nano or Uno.

Converts digital FlexFuel sensor data (50~150 Hz) into analog (0-5v or 0.5-4.5v), for tuners, datalogs, and in-dash gauges.

Pins

Type	Pin	Description
Sensor In	D8	TIMER1 / ICP1
PWM Output	D3/D11	Built-in PWM driver
DAC Output	A4/A5	MCP4725 12bit DAC

Hz -> E % -> V

Input (Hz)	E (%)	Output (V)
50 hz	0 %	0.50v
100 hz	50 %	2.25v
150 hz	100%	4.50v
Errors
< 50 hz	---	4.80v - contaminated
> 150 hz	---	4.90v - high water level
<= 0 hz	---	0.10v - disconnected

License

MIT © Nicholas Berlette