Thanks Eric for the suggestion. I'll have to figure out the inductive circuit to use. Do I have to use interrupts or is there something better for capturing the signal from the pickup?
On Sunday, April 6, 2014 1:51:07 PM UTC-5, Eric wrote: > > an inductive pickup around the sparkplug wire should get you a nice pulse > each time the spark plug fires but remember the phases of a 4 stroke engine > (intake - piston down intake valve open, compression - piston up valves > closed, power - piston down valves closed, exhaust - piston up exhaust > valve open). The spark plug only fires every other revolution. Once you > have the pulse from the inductive pickup it should be buffered to provide a > nice square wave pulse of uniform voltage such that it's easy for the > processor to use and not a potential hazard to the processor due to > spurious high voltages (cooking the buffer circuit while in development, > sorta ok.... cooking the processor, well not so much!) > . from there it's just software and the incrementing of a counter with > each pulse. > > > > > On Sun, Apr 6, 2014 at 6:33 AM, Stacy Cottles <[email protected]<javascript:> > > wrote: > >> I am building a web-controlled lawn-mower. I would like to be able to >> read the RPM off the gas-engine. I would prefer to piggy-back off of the >> spark-plug if possible since it fires faster as the engine spins faster. >> Just started on this but would love suggestions. I have a Beaglebone Black >> running Angstrom and I am using NodeJS to control GPIOs. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
