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Ignition for moped

tomcer34

Nov 20, 2021
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I have several problems. I have one working with HV transformer from CRT TV. But, it has power consumption problem, not good for endurance racing. Started making new, with original ignition coil, but ran into problem. It is out of synchronization with engine. My pick up sensor is hall sensor. I want to make my ignition to spark, when sensor picks up the signal, I know, there will be delay, this delay will be used for timing curve(engine is two stroke). Is there circuit, when sensor goes low (or high, will probably use NAND), it will output signal to the mosfet for 300us. Wanted to use Ne555 monostable configuration, but time will start counting, when signal from hall goes high again. So when engine will stall, it basically goes short circuit. It there any diagram or something? Sorry for my English. If you don't understand something, feel free to ask me and I will try to explain it better. Also, I can post signal diagrams or oscilloscope shots
 

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Delta Prime

Jul 29, 2020
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Make and model of your moped?
I believe your entire premise is wrong but that's only because of lack of information.
Provide all information you have.
With clear focused photos without artifacts. As stated in the above post.
 
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kellys_eye

Jun 25, 2010
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The hall effect device should trigger a one-shot monostable. These do not default to 'permanently on' when the trigger signal 'stalls'.
 

Bluejets

Oct 5, 2014
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One can buy a cdi unit in a variety of power supply applications to suit whatever your bike produces.
Cheap as on Ebay etc. 12v dc...or supply via 400dc or ac from alternator.
Some will even work with existing p/u coils.
Common for the cdi to fire after controlled delay, not the way you describe as it will not work.
Unit consists of the black box, spark plug, cdi coil, pick up or/....... individual parts.
We use them all the time now on miniature engines we build as it is simply cheaper/quicker/more reliable than diy.
(overall cost around 20 to 30 bucks..... depends where you get it)

Just one of a gazillion examples
https://www.ebay.com.au/itm/281930883133
 

tomcer34

Nov 20, 2021
23
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Nov 20, 2021
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Make and model of your moped?
I believe your entire premise is wrong but that's only because of lack of information.
Provide all information you have.
With clear focused photos without artifacts. As stated in the above post.
Moped is Jawa Babetta 210. Maker is Jawa. Original ignition was CDI. Original sensor was induction based.
 

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tomcer34

Nov 20, 2021
23
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Nov 20, 2021
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The hall effect device should trigger a one-shot monostable. These do not default to 'permanently on' when the trigger signal 'stalls'.
It's ordinary hall sensor, for which I made new stator, where it's placed. So when it detects magnetic field, signal goes low, when there is no magnetic field, output goes High
 

tomcer34

Nov 20, 2021
23
Joined
Nov 20, 2021
Messages
23
One can buy a cdi unit in a variety of power supply applications to suit whatever your bike produces.
Cheap as on Ebay etc. 12v dc...or supply via 400dc or ac from alternator.
Some will even work with existing p/u coils.
Common for the cdi to fire after controlled delay, not the way you describe as it will not work.
Unit consists of the black box, spark plug, cdi coil, pick up or/....... individual parts.
We use them all the time now on miniature engines we build as it is simply cheaper/quicker/more reliable than diy.
(overall cost around 20 to 30 bucks..... depends where you get it)

Just one of a gazillion examples
https://www.ebay.com.au/itm/281930883133
Yeah, but I don't want the simple way. Also, I want to learn something new, in Uni I won't study power electronics, so with projects like this, I want to learn something new
 

kellys_eye

Jun 25, 2010
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It's ordinary hall sensor, for which I made new stator, where it's placed. So when it detects magnetic field, signal goes low, when there is no magnetic field, output goes High
Your original post wasn't entirely clear as to the issue you're facing but I understood this to be that your current system is 'switched on permanently' (causing the FET to blow) if the stator stops where the hall effect device is.

The FET (or whatever switching component you use) should be driven by a ONE SHOT monostable. This is triggered by your hall sensor but will only output a pulse for a FIXED duration, even if the stator stalls and the hall effect is permanently triggered. No mmore shorted components.

But all this is on the assumption I've properly understood your original question.....(??)
 

Alec_t

Jul 7, 2015
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Which FET are you using (I can't read the text on your schematic)? If it's not a logic-level type you will have problems.
 
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