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Hey,

Have created another small project. It is digital ignition advance angle display for scooters with CDI. It takes signal from pickup coil and signal from wire wound around spark plug wire, does the math and displays RPM and advance degrees. Has button to adjust pickup coil signal degrees BTDC.

Code: https://github.com/rverzinkevicius/ignition_advance

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Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and '66 Blue Badge Smallframe
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Re: digital ignition advance display
isdeekelis wrote:
Hey,

Have created another small project. It is digital ignition advance angle display for scooters with CDI. It takes signal from pickup coil and signal from wire wound around spark plug wire, does the math and displays RPM and advance degrees. Has button to adjust pickup coil signal degrees BTDC.

Code: https://github.com/rverzinkevicius/ignition_advance
Looks very interesting. I guess this won't work on a 2 stroke Vespa with Ducati CDI?
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Offhand, I don't see why it wouldn't work with some modifications to the software.

Interesting project!
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Will it work on a 2 cylinder motor where both plugs fire simultaneously but the firing order is 360° out of phase (if that makes sense)?
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I think yes. There are few conditions for this to work: you need to have pickup coil and not contact ignition. You need to know how many degrees BTDC pickup generates signal. Also voltage of pickup coil should not be more than 3 volts in order not to damage esp8266.

Current code also has output for timing light, which requires 2n2222 transistor, 200 ohm resistor and LED. But i have noticed that advance mark is jumping few degrees at idle while checking with timing light and don't know why...
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isdeekelis wrote:
But i have noticed that advance mark is jumping few degrees at idle while checking with timing light and don't know why...
On your unit?
All I know is that using the Ducati type ignition (which is static rather than variable) you should set the ignition timing at around 3000 rpm on say, a PX. You'll see the timing move with the light on it lower than that... not a lot but enough to require setting at the higher speed.

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Same jumping both with usual timing light and timing light controlled by my unit.
I thought on usual timing light jumping is due to noise generated by coil/plug, so you first see light splash during spark and then several splashes afterwards generated by noise. I tried to eliminate this effect in code by ignoring subsequent voltage spikes after first one, but it looks like ignition is indeed jumping few degrees forth, but not back (retards, but not advances more than set).
Will check if signal from ecu sent to ignition coil is also jumping.

Anyway, i see correct advance degrees on screen and it doesn't jump and this was my goal.
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Although code handles noise, that noise is strong enough to trigger resistor which lights LED. Removing sensing wire from spark plug wire and simply holding it in hand (body works as antenna) eliminates jumping! So i need some circuit to reduce sensitivity.
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Success! Simple 0.01uF capacitor between spark sensing pin and GND solved it. Now mark is steady at idle.
Will try to draw schematic for whole this thing.

https://github.com/rverzinkevicius/ignition_advance/blob/master/tl.mp4?raw=true
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I would add some transient suppression diodes to the spark and pickup inputs to protect the processor. There's nothing to limit voltage spikes from either source.

For example:
https://www.digikey.com/en/datasheets/littelfuseinc/littelfuse-inc-littelfuse_tvs_diode_sa_datasheet
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Should be it:

External inline image provided by member with no explanatory text


By the way there is file "ignition_advance.bin" in github page. It is already compiled and there is no need to have Arduino IDE with all connected libraries. Just use https://github.com/nodemcu/nodemcu-flasher
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hi, I found this project very interesting, but when I try to compile it it gives me errors! would you give me help?
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