He probably means a “pulse train” (square wave pulses) coming off of a Hall Effect Sensor.
Posted by: nau Posted on: Today at 14:57:11
now it’s pretty clear for me about EEPROM
thank you very much!
i’m trying to measure RPM
i have i wire goin from HALL IC thru CDI which gives DC 12v when engine is stopped and AC when engine is running
nau, have you observed the pulses (what you call AC) by oscilloscope? What are the peak volts of the pulses? Are the pulses directly from the engine shaft?
These pulses are probably in numbers proportionate to engine rpm.
Does your jetski already have a tach?
One method used for measuring RPM by electronic tach is:
taking pulses from the ignition (or where ever) feeding them to an LM2917 frequency to voltage converter (lm2917 - Bing) and (http://cache.national.com/ds/LM/LM2907.pdf)
The LM2917 will output a varying dc voltage, which varies in amplitude in proportion to the pulse frequency of the input. Pulse frequency is (should be) proportionate to rpm.
(http://cache.national.com/ds/LM/LM2907.pdf) gives diagrams.
Another thing you could try.
Since the hall effect pulses are probably proportionate to rpm (I’m supposing here), 1)apply those pulses to your arduino,[be sure the pulses are at the proper peak voltage, (5v?)(3.3v?) or less?, before feeding them to your arduino] 2) code the arduino to count the pulses per second. 3) you might need to use some math to display the counted puses as rpm.
I’ve used both of these methods on a motorcycle. I save the counted pulses per second on an SD CARD.