I am currently working on a DIY quickshifter. This stops the spark for a very short time when changing up gears so that gears can be changed at full throttle.
I have a working circuit, but it currently has no protection from load dumps or transient voltages.
The quickshifter will be controlled by an Arduino microcontroller. When a gear change is detected the Arduino will stop the coils from sparking for a number of milliseconds.
Here is a basic circuit of how the coils are fired.
The red wire connected to the Pri pin on the ECU supplies a constant 12V to the primary coils. Once a signal is recieved by the relevant PNP transister the 12V feed is stopped momentarily and this causes a spark to fire.
I plan to cut the wire feeding the primary circuit of the coils between A and B and then connect these wires to my Arduino circuit. This circuit will be powered by another wire, labelled C above.
Here is the circuit I want to add to the motorcycle.
I need to add some protection to this circuit to protect the MOSFET and MOSFET driver. The datasheet of the MOSFET driver advises to use a bypass capacitor but doesn't mention the size I would need to use.
Please can someone recommend some improvements to this circuit in order for it to be protected when in use on a motorcycle.