// This Arduino Uno code for a single cylinder bike, it reads an input pulse and outputs a SCR pulse with a delay determined by RPM.
// I found it online and I bench tested it with a dual beam scope and it looks like it will work well enough for me, but for one issue.
// Q: I'd like to mute off the SCR pulse on pin 0 below 1500rpm (enabling me to use an available later fixed 10 deg. BTDC SCR pulse for better stability).
// Is there simple mod to this code that would do this? See // following 'attach interrupt'. Cheers!
Mod: added Code tags to your program text.
// I found it online and I bench tested it with a dual beam scope and it looks like it will work well enough for me, but for one issue.
// Q: I'd like to mute off the SCR pulse on pin 0 below 1500rpm (enabling me to use an available later fixed 10 deg. BTDC SCR pulse for better stability).
// Is there simple mod to this code that would do this? See // following 'attach interrupt'. Cheers!
Mod: added Code tags to your program text.
C-like:
#include <math.h>
#include <avr/power.h>
int trig = 2;
int led = 3;
int SCR = 0;
int deg_retard = 0;
long spark_time = 0;
long micro_wait;
unsigned long micro_per_deg;
//rpm stuff
volatile byte trigger_count;
unsigned long rpm;
unsigned long timeold;
void setup()
{
if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
pinMode(trig, INPUT);
pinMode(SCR, OUTPUT);
pinMode(led, OUTPUT);
attachInterrupt( 0, pulse, FALLING);
}
void loop()
{
if (trigger_count > 0) {
micro_per_deg = (micros()-timeold)/180;
timeold = micros();
trigger_count = 0;
if (micro_per_deg >= 110){deg_retard = 55;} // retards 55 deg. below 1500 rpm
// I want to mute off the output SCR pulse below 1500rpm
// I thought deleting this line might do it, I tried that, it all still verifies but still doesn't mute it.
if (micro_per_deg < 110 && micro_per_deg > 55){deg_retard = 45;} // retards 45 deg. between about 1500 and 3000 rpm
if (micro_per_deg < 55 ){deg_retard = 35;} // retards about 35 deg. above 3000 rpm
micro_wait = deg_retard*micro_per_deg;
}
}
void pulse()
{
trigger_count++;
fire();
}
void fire()
{
delayMicroseconds(micro_wait);
digitalWrite(SCR,HIGH); //sends transistor high
delayMicroseconds(350); // spark duration 350uS
digitalWrite(SCR,LOW); //Transistor goes low
}
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