Home built ignition generator unit

[ed knesl]

[quote="Steve Tee"]Howdy Greg,

Before applying power to the completed circuit, you must add that pesky little condenser to your coil. These are cheap, yet essential to the operation of most cars.
Put that little fella on your coil, like you see in the pics on my website, and you'll also be protecting your electronics from the greater part of the sharp voltage excursions that occur on the fet's Drain circuit.
These are available from any auto parts dealer.

Hinote has added a picture of the type of part you will need.

Many different sorts exist on the parts shelves. Any one of these will do the job, so you might want to select one that is mechanically easy to apply to your project.

Hello, Steve !

I just finished my two "buzz boxes" per your schematics and instructions. Tested on stereo headphones before mosfet attachment produces great
200 Hz buzz, just like pulse jets ! Great stuff !
Thanks, it was a sucess.

Just one question - many of these automotive coils have also a resistor
installed at he positive terminal. Do we need any, or the curcuitry
of this system takes care of that.
Also, must the condenser polarity be somehow matched with the coil
terminals ? Should the wire from the condenser be connected to positive
or negative coil terminal ?
Than the can sheathing clip gets connected to opposite one, right ?

Thanks a million !

Ed

[El-Kablooey]

you don't need the resistor, and the lead from the condensor is positive, the can's shell should be grounded (usually grounded on car's body through the mounting bracket)

[Dang911]

Post that video on your web site, cause I never could watch it, but it looks real cool.

My spark are fine. About 2-2.5cm which means 20,000-25,000 volts.
I couldn't ask for juicer, they are just what I need.

When it was semi working, I did light some paper and alcohol on fire for testing purposes (pyro).

Now remember its totally not working right now = no sparks.

[ed knesl]

you don't need the resistor, and the lead from the condensor is positive, the can's shell should be grounded (usually grounded on car's body through the mounting bracket)

Thanks for quick response.

Yes, on the car, the can is grounded, how about here - should be connected
directly to coil negative terminal ? Steve had these terminals interconnected
with the condenser. I think that should be done - right ?

Ed

[El-Kablooey]

yeah, just connect the lead to the 12v+ and connect the can clip to the 12v- with a screw , and round connectors

[ed knesl]

It wasn't too dificult to built Steve's ignitor ( Once you collect all needed
know how and parts ).

Now it is all running with very juicy spark and continuous buzz.

Highly recommended !

Ed

[Steve Tee]

Howdy Ed,

That's great news.
Testing it with the stereo headphones is a great way to check that the circuit is working, and is a good way to 'enjoy the sound of a pulsejet' without deafening the neighbours :) .

Your coil does not need the resistor, but will not be harmed by fitting it.

If the resistor is fitted, it may slightly reduce the power of the spark while reducing the overall DC current draw from the battery.

The condenser is happy to go in any direction on the terminals of the coil. These are AC devices, so there is no chance of harming it by reversed installation.
I have connected my condenser direcly across the coil in order to be sure the coil enters resonance, regardless of over circuit impedance.

In terms of AC, the condenser is direcly connected across the coil in a car.
Even though it is connected across the points in a car, its relationship to the spark coil is one of parallel connection, due to the low impedance of the vehicle's electrical system.

My other reason for placing the condensor directly on top of the coil, is to ensure that the resonance path is localized, and not distributed around the Mosfet and 555 circuit.
High frequency AC is a wierd beast, and needs to be 'tamed', so it doesn't bite :) .


Please be sure to connect the metal body of the spark coil to DC negative, like it is in a car.
This helps to prevent any unwanted shocks, should a spark jump onto the coil's outer shell.
It also ensures that the spark energy is localised to the coil, and its associated high tension outlet lead.


I hope to see pics of your new 'spark-o-tron 2005s' soon :) .


Best wishes, and powerful sparks,


Steve.

you don't need the resistor, and the lead from the condensor is positive, the can's shell should be grounded (usually grounded on car's body through the mounting bracket)

Thanks for quick response.

Yes, on the car, the can is grounded, how about here - should be connected
directly to coil negative terminal ? Steve had these terminals interconnected
with the condenser. I think that should be done - right ?

Ed

[ed knesl]

[quote="Steve Tee"]

Please be sure to connect the metal body of the spark coil to DC negative, like it is in a car.
This helps to prevent any unwanted shocks, should a spark jump onto the coil's outer shell.
It also ensures that the spark energy is localised to the coil, and its associated high tension outlet lead.


I hope to see pics of your new 'spark-o-tron 2005s' soon :) .


Hello, Steve,

I will do connect the coil body to battery negative lead - Thanks for your
help.

Got two of them running good, one as the spare.
It ignites the engine instantly as soon as fuel reaches CC, than little air
and here she goes !

Like the name " Spark-o-tron". I will post the pictures.

Just one little comment. If you would, please, include some of these
late clarifications on the web site, than the guys like me, would not
bother you with some basic questions all the time .

Again, it was a fun project and works flawlessly - got hit only once
* so far * wearing thick glowes now and installed a switch on battery
positive terminal.

A great contribution from you - Thanks !

Ed

[Dang911]

Hi all,

After taking some time to go over what you have all said, I came to some observations and questions.

First I noticed instead of using a 47uf capacitor I used a 0.47 uf. Now I would think this is a problem, but it did work fine at first. Can anyone tell me what the exact effects are by me doing this, and if it needs to be replaced with the correct 47uf.

Secondly, I replaced a blown transistor, and at least I am back to getting my one spark per touch of the battery. I have resisted using the circuit because I still haven't got the 0.5uf condenser capacitor, and I don't want to hurt anything any more than I already have.

Now probably the most important question I have asked, and it might sound stupid, but hear me out.

When I operate the circuit using the coil, I form a spark between the ground wire (connected to the same spot as gate of mosphet, negative) and the wire that comes from the center of the ignition coil. Have I been doing things all wrong here?

It kinda came to me that once the spark jumps, it has to go somewhere, and that would be into the ground/negative/gate of the mosphet, and the battery.

Also one other small stupid question, where is the ground suppose to connect to. (so far, if I have understood right, the negative terminal of the battery, the outer shell of the ignition coil, and gate of the Mosphet, should all be hooked together)

Thanks for everyones help,
Greg

[Lawrence]

Yesss! :D I finaly got this circuit working stable!!

All the components are staying at normal temperature (using 2 irf640 FETs without heatsink)

And as steve says on his site, don't use a battery charger as a power source.. I've used this all the time while debugging the circuit, and when it finally worked, the FET would burn everytime the spark gap got too large..
Now I use a motorcycle battery, wich solved that final problem.

I've used those soldering feet often used for IC's for almost every part, that works really great when changing parts without messing up the solder work.

[Dang911]

Hi all,

After taking some time to go over what you have all said, I came to some observations and questions.

First I noticed instead of using a 47uf capacitor I used a 0.47 uf. Now I would think this is a problem, but it did work fine at first. Can anyone tell me what the exact effects are by me doing this, and if it needs to be replaced with the correct 47uf.

Secondly, I replaced a blown transistor, and at least I am back to getting my one spark per touch of the battery. I have resisted using the circuit because I still haven't got the 0.5uf condenser capacitor, and I don't want to hurt anything any more than I already have.

Now probably the most important question I have asked, and it might sound stupid, but hear me out.

When I operate the circuit using the coil, I form a spark between the ground wire (connected to the same spot as gate of mosphet, negative) and the wire that comes from the center of the ignition coil. Have I been doing things all wrong here?

It kinda came to me that once the spark jumps, it has to go somewhere, and that would be into the ground/negative/gate of the mosphet, and the battery.

Also one other small stupid question, where is the ground suppose to connect to. (so far, if I have understood right, the negative terminal of the battery, the outer shell of the ignition coil, and gate of the Mosphet, should all be hooked together)

Thanks for everyones help,
Greg

PS: sorry to repost but it kinda got covered up with a pointless comment.

[Steve Tee]

Howdy Greg,

Sorry for not replying before now, just got back from business trip.

Yup, you need a 47uF capacitor. One of greater value is fine, but it is best not to go much below 47uF.
The circuit may appear to be working correctly, but an oscilloscope will soon show that the DC supply on the 555 is imperfect.
This can easily cause the 555 to operate erratically.

The 0.1uf cap is there to stop high frequency noise from affecting the 555 and, you guessed it, the 47uF is there to absorb low frequency hash.

To test your circuit, apply a fairly beefy speaker to the point where your spark coil is meant to go.
If all is well, you'll produce a hell of a racket :twisted: .


Your sparks should not leave the local electrical environment of the spark coil.
To ensure this, during initial testing, make sure that there is nothing connected to the centre of the coil.
This will keep the sparks from escaping into the more sensitive areas of the circuit.
Because you do not have a condenser across your coil, you are imparting potentially destructive voltages to the Mosfet.

Once working correctly, your sparks will emerge from the centre of the coil and go onto either of the 2 electrical connectors that occupy the top of the coil body.
Sometimes, a spark may go to the metal body of the coil.
In the latter case, that is where your ground (Battery negative) lead, prevents harmful voltages from getting to the circuit.

The term "Ground", refers to the negative terminal of the battery. An example of this can be seen in cars.
The negative terminal of the battery is connected to the car's body, thereby serving as the ground for the electrical system.

The same is applicable in older cars that have the battery's positive terminal connected to the car's body. In this case, the positive terminal is 'Grounded'.

Uhhhmmm, by "Gate of the Mosfet", you are referring to the Mosfet's Source lead, right?
The Gate should be connected to the drive point at the centre of Q1 and Q2, and the Source lead should be at Ground (B-) potential.


Pointless comment?, errrr .... where?
So far, all that I have seen is positive and constructive stuff.


Best wishes, and may your sparks be good ones,

Steve.

[Dang911]

WELL GUYS,

My battle is OVER!!!

All the sparks I want, JUST FOR ME.

It turns out (and yes I will be honest here), that for some reason I was dead set I had my 555 in right, and never bothered to check it was in backward. Even after replacing 3 I kept placing them in the same WRONG way. It all started when I blew my diode with reverse current, I said "well better replace the 555 too," since that early stage nothing else was wrong, just the 555.

Now for some interesting things I have noticed:

I said what the HELL, I have been running my circuit without a condenser capacitor for probably over an hour, nothing bad has happened, not to mention I still have a 0.47uf capacitor cause I didn't get a response to that question until now.

I did find something "shocking" As I hooked up this unit to my pulse jet's plug I herd a pop when I added fuel (good it works), nothing shocking there. BUT when I would hook the unit to something like a 2 min homemade Jacobs ladder, I noticed that if I touch my grounded metal box that houses the circuit I will get a hell of a shock, practically took over my arm, no harm done though.
I just surprised me cause nothing went bad even though 30,000v was surrounding my circuit, and probably going into the gate of my moose.

I do plan to fix the 0.47uf capacitor and putting on a condenser capacitor.

I would just like to say thanks to all who have helped mainly you Steve, because now that I am up and running, and have a pretty good idea of how to diagnose a problem, I can maintain it myself.

Thanks again,
Greg

[Steve Tee]

Hi Greg,

That's mighty fine news :D .

You'll soon be firing up that engine, and the neighbour's dog will no longer be hit by flying sparklers :twisted:


The shock that you got from the cabinet might have come from the Drain circuit of your 'Moose'.
When a Moose is angry, they'll do anything to get back at you 8) .

To avoid further Moose attacks, you may need to earth both the base and the lid of your metal cabinet. Aluminium has an odd little habit of developing an oxide layer that can insulate it from other metal parts.
By earthing both parts, you should be able to tame the Moose :wink:

Once you have the condenser on your spark coil, you should get even bigger and juicier sparks. Your jet engine will love you for it :D


May your sparks be great, and your engines roar with pleasure.


Best wishes,

Steve.

[francisco]

this is article of rc model, español

circuitos de ignicion para pulsorreactores