The weather is shaping up and the riding weather is here. I’m finally getting motivated to write about the side project adventure that I’ve been kicking around with the help of a few friends. I’ve been fortunate to get to know some talented individuals whose expertise lie in hardware and firmware design. So naturally I’ve made it a point to bother and annoy them into helping create a digital ignition for CB and other points platforms.
If all goes well I wish to offer it to anyone that would find it worth while, which I believe from a feature set vs price standpoint it will be when all is said and done. I'm sure it will not be for everyone, the few non microprocessor based iggys being sold are excellent units and suit/satisfy most very well. This will guy will hopefully satisfy a gap between the base ignitions and high end versions for those wanting a bit more flavor without breaking the bank.
The idea to pursue an ignition was picked up when fabbing my turbo CB, thinking that a digital iggy for controlling spark timing while in boost would be a benefit to have. Seeing the steep price for what was available, the idea to offer an equivalent and less expensive iggy that was bomb proof was attractive and fun project. It was a year+ ago that I made the development platform (motor, magnet rotor, power supply, magnet sensor) for Eric the firmware coder to play with in order to start writing code. But the idea drifted a bit until fall/winter this last year when I finally took the time to write up some specification for him to code toward. After the specs were loosely written down, my friend Eugene crafted the first rev of hardware schematics, and earlier this year I ordered and assembled 5 proto/test units. The project has been a great learning experience to say the least! Coming from an electronic tech background I’ve been most fortunate to be able to be the glue between it all.
For a general description the iggy is a magnetic hall effect pickup based microprocessor controlled ignition. It has its own CNCed rotor and hall sensor PCB plate that replaces the stock CB’s points and advancer unit. Controlling the advance/retard of the spark gives quite a bit of options and flexibility/control. Currently the iggy uses two hall sensors and one magnet, but that is being changed for a single bipolar latching hall and two magnets to help reduce setup error offset (will touch on this later). The main board has three rotary switches for setting parameters, two LEDs: one for 'power on' and one for setting TDC, as well as a handful of I/O wires. The feature set is most equivalent to a Dyna 2000 if it were to be compared to another with some unique features of its own.
The current feature list is loosely set and can be added to or subtracted. There will for sure be one (knock on wood) more hardware spin and then hopefully will be considered a releasable candidate. I will say that I’d be interested in hearing any suggestion that would make this guy better. If anyone has any comments for better or worse I’d appreciate the feed back. It’s still quite early in the project’s development and as noted, features can be added and removed. What features would you like to see or have access to?
The iggy hasn’t ran a bike yet, just a set of plugs on the bench. I just received the first prototype CNC rotor and I’m excited to be able to start testing with the bike soon. I am in the process of getting the bike out of hibernation and waiting for a new release of firmware that incorporates an improved acceleration algorithm.
I’ll pick apart the specs and shed additional detail and test info in future updates to this thread when time permits. Below is the “loose” spec list that is currently built into the rev 1 hardware and is subject to change. (Sorry for the wall of text in this post).
Current feature set, Release Candidate 1 code base (sorry for the few ported formatting oopsies)
* Low RPM power savings with equivalent spark energy vs stock points (edited to remove better)
o ~70% less current draw from stock coils at 1200RPM w/ equivalent spark energy
o ~50% less current draw from stock coils at 2000RPM w/ equivalent spark energy
o ~22% less current draw from stock coils at 3000RPM w/ equivalent spark energy
o Matches or exceeds stock coil current draw from 3800RPM to red-line (yet to be set in stone: how much to exceed stock spark energy vs consume too much current)
o Optimal for additional battery loads (hot coils, pumps, lights) in town stop and go traffic riding conditions
* Spark Timing control rotary (2500RPM to red line)
o Advance: 2-16 degrees in 2 degree increments
o Retard: 2-14 degrees in 2 degree increments
o OFF
o from 1000 to 2500 (full advance) spark event advances from 10 degrees to 35 degrees; stock CB750 profile (or CB550 ect..)
* RPM limit control rotary
o 6000 - 13,000 RPM limit in 500 RPM increments
o OFF
* Shift Light Indicator or RPM activated trigger control rotary
o 6000 - 13,000 RPM set points in 500 RPM increments
o OFF
o Able to sink 2.5A (3A max) of accessory current (shift light, relay, small pump, ect)
* Boost/Vacuum switch enabled timing control
o Advance or retard timing based on trigger events from a external pressure or vacuum switch
o Allows stock timing profile until pressure/vacuum switch event. After switch event timing retards or advances to the setting dialed on the timing set rotary switch.
o Pull timing with boosted applications (Boost Pressure Switch)
o Advance timing for greater motor efficiency/fuel economy with high vacuum steady RPM cruising (VOES Switch)
* Digital tachometer output
o 5V output
o outputs 1:1 true RPM.
* Security disable
o Grounding the security disable control wire disables spark output
* Timing light (strobe) for dynamic timing verification
o Connector on hall sensor board allows for a LED timing light accessory to be plugged in
o timing light drive circuit build into main board (yet to be implemented on current Rev 1 hardware)
* With ignition on, coils stop drawing current when no crank rotations are detected after a certain time period
Current Electrical Features
* Robust design with reliability as #1 underlying goal
o Tantalum (dry) capacitors in place of Electrolytic (wet) capacitors
o IGBT coil current control
o Reverse battery protection
o External input/output wires clamp protected from environmentally noisy EMI energy to prevent damage to sensitive on board electronics
o External input/output wires terminated directly to main circuit board (no connectors)
o All PCB components specified for a minimum of 105C/221F, processor rated at 140C/284F
o PCB encapsulated in hybrid epoxy elastomer, ultimate in weather proofing
+ Excellent thermal cycling performance
+ Supple 37ShoreA hardness
+ Exceptional encapsulating shield
o Sealed Rotary DIP switches
o EMI Shielded cable connects Main board to hall sensor rotor board
* Crank position data provided by dual magnetic Hall sensor (changing to 1 hall 2 magnets)
* 5-3ohm compliant, possibly 2.2-1.5ohm coils (needs test coils and heat testing)
* Low current draw
* 20MHz processor operating speed
* Power On LED
* Cylinders 1/4 Top Dead Center indicator LED
* Small enclosure foot print (approximately 3"x2"x0.6" w/ two 0.5" mounting tabs)