I am beginning to take on this project as well. Let me know what method you used to cut ignition; I’m told relays are too slow and the ignition coils tend to generate several thousands of volts spike back-emf which can damage simple transistors…
I am thinking of using a MOSFET to ground the ignition coils for the set time interval, hoping to get close to or lower than 50ms ignition cut time throughout all gears and all RPM (won’t really be quick shifting without clutch at lower than 8k rpm, what’s the point of quick shifting without being quick in the first place lol).
I am going to be using a custom shift pedal linkage which will house a simple on-off switch. The way the linkage is designed, the switch will be actuated when the shift linkage is under compression and applying a minor amount of spring loaded pressure on the gear shift drum via a coil spring inside the linkage housing and a simple mechanical mechanism (similar to a piston in cylinder). I think this will be a great way to ensure consistent shifting with even the lightest pressure on the pedal (but enough to actuate the switch).
Although I’ve never worked with Arduino I assume the logic skill level will be similar to C / MATLAB which I am familiar with.
My initial idea is that it will go something like this (general case, no idea on the details yet);
//Continuous scanning for 5v from pedal switch (when un-actuated, 0V)
if 3 =< switch voltage =< 6 //closed circuit from pedal switch
MOSFET gate voltage HIGH //completes circuit from ignition primary coil POSITIVE to chassis ground, cutting ignition
wait (XX)ms //ignition kill time, the transmission dog clutches engage new gearing while transmission “floats” under no torque
MOSFET gate voltage LOW //open switch, coil charges and fires as normal
wait (XXX)ms //prevent multiple ignition cuts at once, fastest possible shifting will be at least with 0.5s interval
end
continue scanning for pedal switch inputs
Some things i’m considering and would appreciate any info on;
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what type of power switch or transistor to use, whether a FET or not (I’m not familiar with these types of components and their pros/cons/requirements, unless logic MOSFET they typically seem to require more than 5v for gate voltage)
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how to do a continuous scan for a switch input and what frequency is each Arduino model capable of? Most likely the difference is negligible and for this project the speed of the system is not a significant detail anyways, it is all happening far faster than could be done manually
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is it even possible to take a current flow through the pedal switch as a signal to the Arduino, what pin to use digital / analog?, i assume it needs a resistor in series to prevent short damage
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what type of delays are there between receiving signals, processing them, applying logic, applying power to pins, etc? to get a general idea
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I think the kill time can be fine tuned by trial and error starting from a slow kill time 100ms+, moving to faster until there is impact of the dog clutches or mis-shifts or other symptoms of being too quick, then easing off the kill time by a safety factor
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The double shift wait time can be fine tuned but probably a set and forget value of 500ms or 750ms should be fine
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what is the simplest way to power the Arduino via vehicle rectifier voltage? Fluctuates between ~12 and ~14v
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When the Arduino powers up, if it is installed in the vehicle and no connection to a pc, will it start running the script for continuous input scanning on its own, is there any kind of time delay? no idea what sequence is followed
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what impact does power interruption have on the arduino, should there be some sort of capacitance in the supplied voltage, any other power safety nets to consider
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Should this system be sensitive to engine EMI?
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What is the smallest or most appropriate platform for this type of project, is an Arduino Nano sufficient, any considerations that come to mind?
I am not aware of any issues with the engine being damaged as someone previously posted… in my experience ignition kill can cause a small qty of un-burnt AF mixture to enter the exhaust manifold causing a small pop, exhaust flames at worst (awesome) nothing that doesn’t already happen on my 2006 SV650N which is running slightly lean at ~12.75 AFR due to slip-on muffler without ECM tuning. I’m not concerned with either and will be trying to match ports, polish the heads, increase compression via reduced head gaskets, swapping exhaust cam for more aggressive cam profile over the winter and adjusting valve clearances, perhaps do another dyno run to see what all the adjustments yield, all assuming the engine doesn’t explode.
Although I’ve never touched an Arduino in my life the opportunities seem endless especially on such a cheap little platform. Another easy feature to implement on the motorcycle is wheelie control via similar power cut (ignition cut) based on gyroscopic sensor input on pitching angle. Don’t know if current systems on the market use this type of power cut for wheelie control, but i assume not, would have to look into the possible issues.
Thanks for any help, I think the quick-shifter is easily one of the best performance modifications to any motorcycle for faster lap times or more consistent shifting and reduced clutch wear & transmission damage.