K8055 12v INPUT ISOLATOR

Kits PC Related Projects
1

HELLO

I WANT TO USE THE K8055 TO MEASURE THE SPEED OF A 2 STROKE MOTORCYCLE ENGINE BY MONITORING THE 12v PULSE TO THE IGNITION COIL

THIS WILL MEAN CONNECTING ONE OF THE DIGITAL INPUTS TO A 12v SOURCE WITH A POSSIBLE ENGINE SPEED OF 10,000 RPM ( 166 Hz I THINK THAT EQUATES TO.

CAN ANYONE SUGGEST ,OR DOES VELLERMAN MAKE, AN OPTICAL ISOLATOR CIRCUIT SUITABLE FOR THIS TO ELIMINATE SPIKES ON THE INPUT AND STEP DOWN TO 5v

ALSO IS THE K8055 FAST ENOUGH TO COPE WITH THIS INPUT, AND IF NOT CAN ANYONE SUGGEST A GOOD FREQUENCY TO VOLTAGE CIRCUIT ALSO OPTICALLY ISOLATED THAT I COULD USE ON THE ANALOGUE INPUT ( AT THE RIGT VOLTAGE OF COURSE )

COULD I ALTERNATIVELY USE A FREQUECY REDUCER ( HALVER ) AND IF SO A CIRCUIT FOR THAT…YOU GET THE IDEA ?

MANY THANKS NICK.

2

The frequency you mentioned is too high for the K8055 to use polling method to read the digital inputs. Instead, you may use the internal counters of the K8055 to measure the engine speed.

Indeed, it is good idea to put optical isolator between the ignition coil voltage and the K8055.