Model engine CDI easy and cheap

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What is the life expectancy of the relay? I thought they couldn't cycle but so many times -- ??

It is using just the coil so life expectancy of a relay doesn't come into it
 
As #180, have added the EDA files here for anyone interested.
Also the final schematics for Hall Effect KY-003 module operation.

Have also included a version schematics for operation with everyday points if anyone so desires.
Note there is no requirement for the "points condensor" as in Kettering system.
Added one of these units to my old Atkinson engine yesterday and results are really good.

Might pay to note that I ran this points unit on 7.4v LiPo battery and it works fine even at that level.
Must remember though it's max rev requirements are probably 2000 rpm and would suit many old timer engines.

Forgot to add value of resistor for the timing LED in the points schematic....... 1k0 1/4w ...cheers
 

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  • Schematic Hall Aug_2022.jpg
    Schematic Hall Aug_2022.jpg
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  • Schematic Points Aug_2022.jpg
    Schematic Points Aug_2022.jpg
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  • Gerber_PCB_CDI_add_On_2022-05-27.zip
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Does anyone have the 12VDC CDI module drawn up with a BOM and gerber files and the like? I want to make my own circuit board for an old hit and miss oil jack pump engine. I cant tell you how long I have been looking for this! Please advise.

Thanks in advance.

- Mark
 
I have but it may be protected info.
Anyhow, you won't even start to build it for the price you can buy the complete system, coil and all.

Many have tried their own uC cdi's in the past with varying levels of success/failure, the latter more prominent.

74Sprint (Ray) I think is currently working on yet another approach, as yet unfinished as far as I know.
Details of that are in the forum here.
 
Come on now, don't go talking bad about my chicken projects. It was something far more sophisticated than a simple "Chicken Waterer". It was a "Solar Synchronized Chicken Coop Door Opener". It had to be sophisticated to make up for the deficiencies in the tiny chicken brains. The door had to be coordinated with the seasonal variations in solar sunrise and sunset. The clocks in chickens are embedded, and cannot be re-programmed. Dusk to dawn timers won't work either, and the chickens will either get trapped inside or outside, and always on the wrong side. And several safety interlocks are necessary so that no chickens get mashed in the operating door. In the end, I don't think the chickens cared one way or the other.
Lloyd, i just now was reading this thread and saw your post. several years ago i was a member of the technology council in SW Virginia and there was mention of someone using technology for the chicken door opener. if i recall the Gov. of Va at the time was even at that meeting. i want to say it was Dutt and Wagner they were mentioning as the egg producer but i could have just assumed that since they are just down the road from me and where the meetings were always held. just sounds like to much of a coincidence that this had to be you that they were talking about. this had to be at least 10 years ago i guess but seems like yesterday.

i see your location is Charlottesville VA so maybe it was you. but i do recall this being mentioned as a huge inovation and how technology and farming were coming together.
 
Lloyd, i just now was reading this thread and saw your post. several years ago i was a member of the technology council in SW Virginia and there was mention of someone using technology for the chicken door opener. if i recall the Gov. of Va at the time was even at that meeting. i want to say it was Dutt and Wagner they were mentioning as the egg producer but i could have just assumed that since they are just down the road from me and where the meetings were always held. just sounds like to much of a coincidence that this had to be you that they were talking about. this had to be at least 10 years ago i guess but seems like yesterday.

i see your location is Charlottesville VA so maybe it was you. but i do recall this being mentioned as a huge inovation and how technology and farming were coming together.
Wow, small world. No, that wasn't me, although I went to VaTech and lived in Floyd County and know my way around that region. Beautiful country, but so is Charlottesville.

The automatic chicken door was just one of those compulsive projects that you put a stupid amount of hours into and it turns out good, but was it a sensible use of your time, LOL. That door is still working with no repairs and no mashed chickens. It had remote LEDs that were visible from a window in the house to show if the door was open or closed or in operation. Fun stuff for sick minds.
 
I have but it may be protected info.
Anyhow, you won't even start to build it for the price you can buy the complete system, coil and all.

Many have tried their own uC cdi's in the past with varying levels of success/failure, the latter more prominent.

74Sprint (Ray) I think is currently working on yet another approach, as yet unfinished as far as I know.
Details of that are in the forum here.
I'm sorry guys that I haven't done much on the programmable ignition lately but the wife has laid down the law with me after I bought 2 snowmobiles. They weren't running but I worked a little magic on them and they fire now but, all the fuel lines need replacing and carbs need to be cleaned, real bad. Anyway I have been working on the yard and house and when that is done I'll finish the programmable ignition. Interesting, both sleds have AC-CDI ignitions with fixed timing and have very little adjustment . . . . for now. TTYL

Cheers
Ray
 
I have but it may be protected info.
Anyhow, you won't even start to build it for the price you can buy the complete system, coil and all.

Many have tried their own uC cdi's in the past with varying levels of success/failure, the latter more prominent.

74Sprint (Ray) I think is currently working on yet another approach, as yet unfinished as far as I know.
Details of that are in the forum here.
BLUEJETS

I am not trying to make this for $. I am trying to get an old engine working again for my father's farm. The CDI module I built only works from a plug-in transformer. I want to just build one DC CDI. I don't want to buy it. I know it sounds stupid to everyone that reads this statement, but I just need to build it. if you can help at all my email is [email protected]
 
Just a bit of an update on what I have been doing. To start with I haven't given up on the programmable ignition, it's right in front of me but, I have been helping out a fellow member (Mark Hamilton) get a more reliable CDI ignition for his 120 year old (I believe) horizontal engine. At the same time I'm trying to work the bugs out of my Sparky-1 CDI ignition and Mark is helping with that by testing it.

When I designed the board and I wanted to try something out with the copper pours on the board. I never really measured the output of this little board and others told me "oh the spark isn't that strong", well they were way off and didn't know squat. Turns out the board is arcing out across 0.070" to the on board ignition coil at between 500-700 volts. I will have to redesign the board the right way. Bread boarded the primary voltage goes to 1,100 volts on 5 volt power supply. Right now using 12.5 volts power supply the current draw is only 0.034 amps! No that is not a typing error. This brings another problem, Mark is using 2 x12 volt truck batteries that are solar charged. The circuitry was never designed to use 12.5 volts, it was meant for 5 volts. So the power output is way to high, never thought I would say that.

I use a CC/CV power supply to limit the current, otherwise it tends to burn things up. We have been looking around to find a cheap current limiter and have tried a few things but, nothing we have tried so far works out. So I'm going to try and design a current limiting circuit I have seen before. If that works then I'll string everything together.



One thing Mark had asked for which, keeps the ignition that he has now and to keep the engine in 1 piece is a RPM limiting cutout circuit. The cutout needs to trip at 500 RPM and remove power to the ignition and stay locked out. Getting something to stay running at 15Hz but trip at 16Hz was not easy (wasted spark). So 450 RPM is ok but, 480 RPM is not. Anyway I ended up using a Frequency-to-Voltage chip (LM2907N-8/NOPB) that is used to make tachometers and it works beautifully and has adjustable trip limit. The chip will work with different signals but can be sensitive to different waveforms. I also found the datasheet and it's formulae to be out to lunch, most of the time. But if you want to make your own tach then this is the chip to use. For the cutout relay (latching) I'm using the standard automotive 30 amp 5 pin relay. You know the pin 30 and 87a stuff. Current draw on this circuit alone is 0.134 amps at 12 volts.

The image below shows the 16Hz (on) and the 2 LEDs show trip limit and cutout on. I don't have a momentary N/C switch in there, I just turn the power off to reset.

Trip 16Hz Signal On.jpg


There are other ways to use this circuitry as a cheap rev limiter on almost any ignition. Next thing to do is the current limiting circuit and a new board design.

Cheers
Ray
 
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