DIY TCI + CDI Trigger
The document provides an extract from another SC article discussing a simple programmable TCI (Transistor Controlled Ignition) that features nearly identical trigger input circuits to the DIY-CDI (Capacitor Discharge Ignition) system. It highlights that the trigger circuits are described in greater detail than in the DIY-CDI article. The DIY-CDI is compatible not only with traditional points but also with various types of trigger signals, including those from factory and aftermarket reluctor, optical, and Hall Effect distributors. It can interface with an ECU ignition output trigger, making it suitable for all single-coil cars, motorcycles, and go-karts. This system serves as an ideal upgrade for older points ignition systems or as a cost-effective replacement for defective factory ignition modules, often at a fraction of the original price.
Reluctor: A reluctor trigger consists of a coil wound around an iron core, with a ring magnet featuring small externally protruding sections (teeth) mounted on the distributor shaft. As each tooth passes the sensor, a voltage is induced in the coil, generating voltage spikes that provide the timing signal. A magneto signal can alternatively be used as a trigger signal for this project.
Optical: An optical trigger includes a LED and a phototransistor or photodiode. These components are housed in a package that allows light from the LED to reach the photodetector. An opaque vane moves between the LED and the sensor to switch the photodetector on and off. This ignition system accommodates both factory optical systems and commercial optical ignition triggers from brands such as Lumenition, Piranha, and Crane.
Hall Effect: A Hall Effect trigger is a semiconductor device that toggles its output based on the presence or absence of a magnetic field. Typically, the magnet is integrated within the sensor package, allowing for easy triggering by passing an iron vane through the sensor gap. The Hall Effect unit activates when the iron vane is removed.
ECU: In single-coil vehicles with engine management, the ECU signals the ignition module when to interrupt current flow to the coil. This signal is usually a 5V square wave.
Points Debounce: Points debounce is necessary because points do not open or close cleanly. When closing, points can bounce open, similar to a hammer rebounding off a steel plate, resulting in rapid openings and closings. During opening, the points can also bounce due to slight play in the distributor shaft. By setting the minimum spark duration to 1ms, the coil fires cleanly as the points initially open, ensuring a full spark duration before the coil discharges. If the coil is allowed to charge again before the points close, a second spark may occur from point bounce, potentially igniting an engine cylinder at an inappropriate time.
Voltage Level Sense: Given the variety of triggers that can be utilized, there is an option to modify the voltage level sense that determines the ignition firing point. For points, the firing point occurs when the points open, causing the voltage to rise from 0V to 12V. For other sensors, such as Hall Effect or optical triggers, the voltage sense may vary depending on whether the ignition firing point is triggered by the entry or exit of the vane from the sensor. A simple jumper change allows for the selection of the required voltage sense.
The schematic includes six input trigger circuits: (a) points triggering; (b) Hall Effect (and Lumenition) triggering; (c) triggering from an engine management module; (d) reluctor pickup; (e) Crane optical pickup; and (f) Piranha optical pickup. The points input is illustrated in the corresponding schematic.
The programmable TCI system is designed to enhance ignition performance and reliability across a wide range of applications, making it a versatile solution for automotive and motorcycle enthusiasts seeking to upgrade their ignition systems.Extract of another SC article which deals with a simple programmable TCI with nearly the same trigger input circuits than DIY-CDI. Good for us, the trigger circuits are describted in more details than the DIY-CDI article. The DIY-CDI will not only will work with traditional points but will also happily function with any type of trigger signal incl
uding those provided by factory and after-market reluctor, optical and Hall Effect distributors. It will even interface with an ECU ignition output trigger, making it a universal fit for all single coil cars, motorcycles and go-karts. It`s the ideal upgrade for an old points ignition system or it can be used to replace a defective factory ignition module for as little as one-fifth of the price.
Reluctor: a reluctor trigger comprises a coil wound around an iron core. A ring magnet with small externally protruding sections (teeth) is installed on the distributor shaft. As each tooth of the magnet passes the sensor, a voltage is developed in the coil. These voltage spikes provide the timing signal. Incidentally, in place of the reluctor, a magneto signal can be used as a suitable trigger signal for this project.
Optical: an optical trigger comprises a LED and a phototransistor or photo diode. The pair is incorporated within a package that allows the light from the LED to impinge on the photodetector. To switch the photodetector on and off, an opaque vane passes between the LED and its sensor. In addition to factory optical systems, this ignition caters for commercial optical ignition triggers such as those from Lumenition, Piranha and Crane.
Hall Effect: a Hall Effect trigger is a semiconductor device that switches its output on or off, depending on the presence or absence of a magnetic field. Generally, the magnet is included within the sensor package and so the sensor is easily triggered by passing an iron vane through the provided gap.
The Hall Effect unit triggers when the iron vane is removed from the gap. ECU: as described above, in single-coil cars with engine management, the ECU signals the ignition module when to switch off current to the coil. This signal is generally a 5V square wave. Points Debounce: points debounce is needed because points tend not to open or close cleanly. When closing, points can bounce back open, just as a hammer does when hitting a steel plate, and this can cause a series of rapid openings and closings.
When opening, the points can also bounce as the distributor cam wobbles, because of slight play in the distributor shaft. By setting the minimum spark duration at 1ms, the coil will fire cleanly as the points first open. This provides the full spark duration and by this time the coil will have discharged. However, if the coil is then allowed to charge up before the points close again, there can be a second spark produced if the points bounce upon closure.
This second spark can produce ignition in one of the engine cylinders at the wrong time. Voltage Level Sense: because of the large number of triggers that can be used, there is an option to change the voltage level sense that determines the firing point for ignition. For points, the firing point is always when the points just open, so in this case the voltage goes positive from 0V to 12V.
For other sensors, the voltage sense may be different. For example with the Hall Effect or optical triggers, it depends on whether the ignition firing point occurs when the vane enters the sensor or leaves the sensor. So at the firing point, the voltage could be going from 0V to a more positive voltage, or from the positive voltage to 0V.
A simple jumper change selects the required sense. Fig. 3: the six input trigger circuits: (a) points triggering; (b) Hall effect (and Lumenition) triggering; (c) triggering from an engine management module; (d) reluctor pickup; (e) Crane optical pickup; and (f) Piranha optical pickup. The points input shown in Fig. 3(a) c 🔗 External reference
Reluctor: A reluctor trigger consists of a coil wound around an iron core, with a ring magnet featuring small externally protruding sections (teeth) mounted on the distributor shaft. As each tooth passes the sensor, a voltage is induced in the coil, generating voltage spikes that provide the timing signal. A magneto signal can alternatively be used as a trigger signal for this project.
Optical: An optical trigger includes a LED and a phototransistor or photodiode. These components are housed in a package that allows light from the LED to reach the photodetector. An opaque vane moves between the LED and the sensor to switch the photodetector on and off. This ignition system accommodates both factory optical systems and commercial optical ignition triggers from brands such as Lumenition, Piranha, and Crane.
Hall Effect: A Hall Effect trigger is a semiconductor device that toggles its output based on the presence or absence of a magnetic field. Typically, the magnet is integrated within the sensor package, allowing for easy triggering by passing an iron vane through the sensor gap. The Hall Effect unit activates when the iron vane is removed.
ECU: In single-coil vehicles with engine management, the ECU signals the ignition module when to interrupt current flow to the coil. This signal is usually a 5V square wave.
Points Debounce: Points debounce is necessary because points do not open or close cleanly. When closing, points can bounce open, similar to a hammer rebounding off a steel plate, resulting in rapid openings and closings. During opening, the points can also bounce due to slight play in the distributor shaft. By setting the minimum spark duration to 1ms, the coil fires cleanly as the points initially open, ensuring a full spark duration before the coil discharges. If the coil is allowed to charge again before the points close, a second spark may occur from point bounce, potentially igniting an engine cylinder at an inappropriate time.
Voltage Level Sense: Given the variety of triggers that can be utilized, there is an option to modify the voltage level sense that determines the ignition firing point. For points, the firing point occurs when the points open, causing the voltage to rise from 0V to 12V. For other sensors, such as Hall Effect or optical triggers, the voltage sense may vary depending on whether the ignition firing point is triggered by the entry or exit of the vane from the sensor. A simple jumper change allows for the selection of the required voltage sense.
The schematic includes six input trigger circuits: (a) points triggering; (b) Hall Effect (and Lumenition) triggering; (c) triggering from an engine management module; (d) reluctor pickup; (e) Crane optical pickup; and (f) Piranha optical pickup. The points input is illustrated in the corresponding schematic.
The programmable TCI system is designed to enhance ignition performance and reliability across a wide range of applications, making it a versatile solution for automotive and motorcycle enthusiasts seeking to upgrade their ignition systems.Extract of another SC article which deals with a simple programmable TCI with nearly the same trigger input circuits than DIY-CDI. Good for us, the trigger circuits are describted in more details than the DIY-CDI article. The DIY-CDI will not only will work with traditional points but will also happily function with any type of trigger signal incl
uding those provided by factory and after-market reluctor, optical and Hall Effect distributors. It will even interface with an ECU ignition output trigger, making it a universal fit for all single coil cars, motorcycles and go-karts. It`s the ideal upgrade for an old points ignition system or it can be used to replace a defective factory ignition module for as little as one-fifth of the price.
Reluctor: a reluctor trigger comprises a coil wound around an iron core. A ring magnet with small externally protruding sections (teeth) is installed on the distributor shaft. As each tooth of the magnet passes the sensor, a voltage is developed in the coil. These voltage spikes provide the timing signal. Incidentally, in place of the reluctor, a magneto signal can be used as a suitable trigger signal for this project.
Optical: an optical trigger comprises a LED and a phototransistor or photo diode. The pair is incorporated within a package that allows the light from the LED to impinge on the photodetector. To switch the photodetector on and off, an opaque vane passes between the LED and its sensor. In addition to factory optical systems, this ignition caters for commercial optical ignition triggers such as those from Lumenition, Piranha and Crane.
Hall Effect: a Hall Effect trigger is a semiconductor device that switches its output on or off, depending on the presence or absence of a magnetic field. Generally, the magnet is included within the sensor package and so the sensor is easily triggered by passing an iron vane through the provided gap.
The Hall Effect unit triggers when the iron vane is removed from the gap. ECU: as described above, in single-coil cars with engine management, the ECU signals the ignition module when to switch off current to the coil. This signal is generally a 5V square wave. Points Debounce: points debounce is needed because points tend not to open or close cleanly. When closing, points can bounce back open, just as a hammer does when hitting a steel plate, and this can cause a series of rapid openings and closings.
When opening, the points can also bounce as the distributor cam wobbles, because of slight play in the distributor shaft. By setting the minimum spark duration at 1ms, the coil will fire cleanly as the points first open. This provides the full spark duration and by this time the coil will have discharged. However, if the coil is then allowed to charge up before the points close again, there can be a second spark produced if the points bounce upon closure.
This second spark can produce ignition in one of the engine cylinders at the wrong time. Voltage Level Sense: because of the large number of triggers that can be used, there is an option to change the voltage level sense that determines the firing point for ignition. For points, the firing point is always when the points just open, so in this case the voltage goes positive from 0V to 12V.
For other sensors, the voltage sense may be different. For example with the Hall Effect or optical triggers, it depends on whether the ignition firing point occurs when the vane enters the sensor or leaves the sensor. So at the firing point, the voltage could be going from 0V to a more positive voltage, or from the positive voltage to 0V.
A simple jumper change selects the required sense. Fig. 3: the six input trigger circuits: (a) points triggering; (b) Hall effect (and Lumenition) triggering; (c) triggering from an engine management module; (d) reluctor pickup; (e) Crane optical pickup; and (f) Piranha optical pickup. The points input shown in Fig. 3(a) c 🔗 External reference
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