Model engine CDI easy and cheap

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BlueJets: I'm trying to order your V2 pcbs at JLCPCB. When I upload the gerber file, I get the attached files. Do I select Panel by JLCPCB? 2 row and 2 columns? Looks like JLCPCB wants to put 5 pcb on each panel.



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That would be 2 rows x 2 columns so "4" pcb's per panel, not 5....then there are 5 panels.
So all up 20 pcb's....but at AUD$14 odd cheap as........

I "panalize" the panel so I can get more pcb's for around the same cost.

It used to be that "panelize" was free but now a small extra charge.

Mine have not yet arrived (only a week or so) but I'll show a photo when they do.

When you upload the Gerber File, there is a "quote" on cost BUT you must select the shipping type.
Some can be $50 if you don't watch it.
I choose to pay by Paypal after assessment is done (not automatic pay) as someimes. like with the panelize option, is not included in the quote.

If you only want 1 pcb per panel, I can redo the drawing and re-post Gerber Files for 1 pcb per panel if that is what you prefer.
That then would be 5 pcb all together.
In addition, you would need to cut the board to size, whereas currently, with the score lines in panelize, it is simply snap off.
Cost would be a little less but I would need to calculate just how much when/if the drawing is modified.
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OK...went back to my original drawings and changed the board setup so that only one pcb is made per panel.
That will give you 5 pcb's in total and you may need to cut to size I imagine (maybe not, never done it that way)
Generated the Gerber File for that as " Version 3 Add On CDI Single" which I will add below as a zip file.

So you need to upload that as a zip file to JLCPCB, select your country up top for delivery and (very important for cheap delivery) I select Global Standard Direct Line which works out at AUD$2.26 delivery with the boards costing AUD$3.01.

Still do the payment via Paypal the way I suggested (after they check the design) and then if any extra cost entailed, it will show in their final price.
I used to make my own boards, never again..........

Note that once the Gerber File is uploaded, you can view the finished product as 2d or 3d. Don't be alarmed that 2d has "missing tracks" as they are there in 3d (underside).


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As above in #202 order arrived and so showing the photos of top and bottom ....these are the "panelized" pcb's 4 pcb's per panel, 5 panels in order.
These are slightly larger than the originals from way back when to allow for the larger traces and solder pads.


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Hi BlueJets, I ordered 5 single boards today from JLCPCB yesterday. I'll update as parts start to come in.
Hi Jerry,

(Bad News) Quick note........ there is an error in the PCB as shown above.

(Good News) Easy fix.

Where P4 from the CDI black box currently goes to P4 on the pcb......... this is INCORRECT. ( there is a track error)
Only noticed it today (8/6/2024)

Fix is to take the P4 wire out of the pcb, drill a 1.0mm hole in the pcb on the right hand side of the top pad for the resistor 1k0, taking care not to damage any track underneath, and solder underneath to that resistor pad.

Sorry for the error but sometimes **** happens I guess.

Circuit diagram is correct........


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Apologies for incorrect pcb although they will work fine with the 1 modification above (re-reroute P4 connection)

Enclosed here is a re-vamped Gerber design file (with correct connections and also a diode added to the input for protection but only if one desires.

Circuit diagram above is as before, correct except for the added protection diode.

Note that the gerber is for "panelized" production....... ie 4 pcb's per panel.......5 panels per order.
Currently being checked for correct at PLCPCB


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The only reference to what you say as I can remember is, this is for the 4 pin DC CDI module which are all the same as far as I know.
Obviously my circuit will not work with the HV (300-400v) 5 or 6 pin units.

One link is here anyhow, just about to order a few more.
In this instance from here at least, if one orders over AUD$15.00 worth, (3 or more) delivery is free.
All I have seen as well, have the blue connector with the 4 internal pins to which I solder whatever length leads I need.
If one wants to use a plug with these, it will be the 6 pin auto type plug 2.8mm.
I plan on building one, just ordered the 4 pin cdi's using your link. I have a couple questions on the completed functioning ignition. What is the upper rpm limit? Could you possibly measure the input impedance of the GY6 scooter coil? The reason I ask is that I plan on substituting a dual output coil for use on a wasted spark inline twin.

I recently bought one of these engines for $149US and would like to convert it from glow plug to spark ignition using gasoline. From my understanding the little beast can rev to nearly 18K rpm.

Thanks much !!!
Looks like spark ignition already?
No, glow plug is standard and rc nitro fuel. they have a spark ignition / gasoline option that is about $200. Besides, I want to build my own to learn for future engine builds. I bought the engine to basically reverse engineer it for educational purposes, cam timing, valve size, piston/ring dimensions etc.
Hi Bluejets, Thanks for the updates on your pc board. I got the boards and that’s a simple error to fix. Still waiting on a couple of parts to come in.
Hi Bluejets, Thanks for the updates on your pc board. I got the boards and that’s a simple error to fix. Still waiting on a couple of parts to come in.
Ah...good to know...thanks for the update.

What is the upper rpm limit? Could you possibly measure the input impedance of the GY6 scooter coil?
No idea on "upper rev limit" as it was never a consideration.
Maybe simply suck it and see.
Suffice to say they were originally used on the mini motorcycles from 50cc and up so I'd imagine around 10k wouldn't be out of the ball park.
As far as getting that thing you linked to upwards of 18k, maybe if the well is deep enough and the cow jumped over the moon.

I have a four cylinder four stroke I built here which goes to 10k on alcohol fuel and I can tell you that is fair buzzing.
Why you would need to go to the levels you mention beats me.

However, with regard to the input impedance of the coil, impedance is a factor of frequency..............

I can give you the dc resistance.
Over 3 coils, a variation from 0.37R to 0.43R using a 4 wire micro ohm meter.
Thanks Bluejets for the info. DC coil resistance was what I should have said.

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