Hi,
I have been working on building a DIY ignition interrupt module for a 4 stroke motorcycle engine. The engine is mounted into a racing sidecar chassis. I have managed to create a circuit on some stripboard which will cut the ignition when a sensor is activated.
Here is a diagram of the ignition system of the motorcycle. This is not exact, just my interpretation, I cannot change this bit of the circuit anyway.
My circuit will connect to this circuit at point C, and also I will cut the wire between points A and B and connect them to my board.
Here is a diagram of my circuit.
The sketch on the Arduino is configured to light up a green LED, connected to pin D9. Once the Arduino detects a LOW signal on pin D2 (when the sensor has been activated), the green LED will be turned off, the red LED on pin D8 will be turned on and also a HIGH signal will be sent out of pin D11 to the MOSFET driver, this will turn off the P-Channel MOSFET and cut power to the ignition coils. After a short period of time (60 ms currently). The Arduino will put everything back to the original state (MOSFET on, RED off, Green on).
I have connected this circuit to my bike, with a 12v bulb connected between the drain and source of the MOSFET. This works as expected, the bulb is turned off for a 60ms period. Once I connect the ignition wires to the MOSEFT, I start to experience false detections. D2 is going LOW when the switch is wide open. I can tell the arduino is detecting that this is going low because the Red LED comes on.
I suspect that this is due to back EMF from the power being cut to the primary circuit of the ignition coils. What can I add to the circuit to stop the false detections? I might be very much mistaken and it could be something else causing the false detections, however, it only occours when the ignition circuit is fed via the MOSFET.
Thanks in advance for any help.
David
I have been working on building a DIY ignition interrupt module for a 4 stroke motorcycle engine. The engine is mounted into a racing sidecar chassis. I have managed to create a circuit on some stripboard which will cut the ignition when a sensor is activated.
Here is a diagram of the ignition system of the motorcycle. This is not exact, just my interpretation, I cannot change this bit of the circuit anyway.
My circuit will connect to this circuit at point C, and also I will cut the wire between points A and B and connect them to my board.
Here is a diagram of my circuit.
The sketch on the Arduino is configured to light up a green LED, connected to pin D9. Once the Arduino detects a LOW signal on pin D2 (when the sensor has been activated), the green LED will be turned off, the red LED on pin D8 will be turned on and also a HIGH signal will be sent out of pin D11 to the MOSFET driver, this will turn off the P-Channel MOSFET and cut power to the ignition coils. After a short period of time (60 ms currently). The Arduino will put everything back to the original state (MOSFET on, RED off, Green on).
I have connected this circuit to my bike, with a 12v bulb connected between the drain and source of the MOSFET. This works as expected, the bulb is turned off for a 60ms period. Once I connect the ignition wires to the MOSEFT, I start to experience false detections. D2 is going LOW when the switch is wide open. I can tell the arduino is detecting that this is going low because the Red LED comes on.
I suspect that this is due to back EMF from the power being cut to the primary circuit of the ignition coils. What can I add to the circuit to stop the false detections? I might be very much mistaken and it could be something else causing the false detections, however, it only occours when the ignition circuit is fed via the MOSFET.
Thanks in advance for any help.
David