DIY Ignition System - Most simple
 

My friend designs and builds ignition system for small converted glow to gas engine. Some info about this project.
- Use FET as a coil drvier
- small coil from commercial motocycle
- Only a few electronic parts
- simple ignition no advance timing
But the performance is excellence.
Here is circuit diagram.

RE: DIY Ignition System - Most simple
 

Circuit board
http://www.rcthai.net/forum/attachme...1&d=1201359027

After install electronic components, compare to the size of standard CDI
http://www.rcthai.net/forum/attachme...1&d=1201359027
http://www.rcthai.net/forum/attachme...1&d=1201359027

RE: DIY Ignition System - Most simple
 

Some coils that can be used
http://www.rcthai.net/forum/attachme...1&d=1201607965
http://www.rcthai.net/forum/attachme...1&d=1201607965
http://www.rcthai.net/forum/attachme...1&d=1201607965

RE: DIY Ignition System - Most simple
 

Test it, over 14000 rpm still work
[link=http://s234.photobucket.com/albums/ee235/copter-new/?action=view&current=3002.flv]http://i234.photobucket.com/albums/e...ew/th_3002.jpg[/link]

RE: DIY Ignition System - Most simple
 

Fantastic runing, much better runing and smoother than commercial CDI with advance timing.
[link=http://s234.photobucket.com/albums/ee235/copter-new/?action=view&current=3003.flv]http://i234.photobucket.com/albums/e...ew/th_3003.jpg[/link]

RE: DIY Ignition System - Most simple
 

There will be new and better version, and more on how to make and testing technique later. Please stay tune.

RE: DIY Ignition System - Most simple
 

kewl

RE: DIY Ignition System - Most simple
 

New version circuit board.
http://www.rcthai.net/forum/attachme...1&d=1201534419

Look better than previos version
http://www.rcthai.net/forum/attachme...1&d=1201545045
http://www.rcthai.net/forum/attachme...1&d=1201545045

Weight only 23 grams.
http://www.rcthai.net/forum/attachme...1&d=1201574395

RE: DIY Ignition System - Most simple
 

Hall sensor wiring
http://www.rcthai.net/forum/attachme...1&d=1201584838

Wrap with heat-shrink tubing
http://www.rcthai.net/forum/attachme...1&d=1201584838

Look professional
http://www.rcthai.net/forum/attachme...1&d=1201584838

RE: DIY Ignition System - Most simple
 

Set up the test bench, using TT50 engine
http://www.rcthai.net/forum/attachme...1&d=1201615852

Now we can speed up to full throttle, more than 10000 rpm. While cheap CDI can go to only 8000 rpm.
[link=http://s234.photobucket.com/albums/ee235/copter-new/?action=view&current=b007.flv]http://i234.photobucket.com/albums/e...ew/th_b007.jpg[/link]

RE: DIY Ignition System - Most simple
 

Very good, keep it coming.

RE: DIY Ignition System - Most simple
 

Thanks Jezmo,
Almost ready weight is about 77 grams.
http://www.rcthai.net/forum/attachme...1&d=1201783730

Less than commercial CDI
http://www.rcthai.net/forum/attachme...1&d=1201574395

RE: DIY Ignition System - Most simple
 

Question, inquiry and comment are welcome.

RE: DIY Ignition System - Most simple
 

Could you explain something to me? Hall sensors have the output tied to ground or to Vcc? I ask this because I cannot find Hall ICs here and a simple switch could be used.
From my experiments with a heavier transistor ignition module, fixed timing is directly implied to either a high idle or low max rpm. Yours seams to run very well with fixed timing, which is puzzling me![sm=spinnyeyes.gif]

As with your heli gas conversion, great job!:D (and thanks for such a nice module! you should try to sell some as a kit ;) )

RE: DIY Ignition System - Most simple
 

Was the engine in the video running on gas or methanol?

RE: DIY Ignition System - Most simple
 

is it cleaner than glow? everytime i called c&h ignition wanting to covert a glow to gas they talked me out of it, saying it's more messy than glow.
is your friend going to sell these? i'll buy if so.
i have a magnum 160 twin that i would love to change over. jeff

RE: DIY Ignition System - Most simple
 

Hey Jeff,
I am surprised the CH guys talked you out of it. Check out my thread in conversions on the SuperTigre 40 CDI. I am now using a 51 but it is certainly less messy than glow unless the fact that the oil that does make it onto the plane is blacker makes it somehow more messy. There is still a fair amount of oil that gets on my plane and it is dark compared to glow fuel but there is quite a bit less oil that gets on it as compared to glow and it is easier to wipe off because it is less viscous. I am not sure what they meant by more messy. All of my CDI stuff came from Bill at CH and it is excellent quality but this stuff bbuldoc is working with is very interesting.

RE: DIY Ignition System - Most simple
 

Yep, .. Hall sensor has three pins. One pin goes to +5V, one pin to ground and the rest one is output. I think this type of hall sensor is easy to find and generally used in many application. If you use simple switch then you don't need LM358. However I think it is difficult to install switch to converted engine.

About the timing, me and my friend thought the same as yours. But until we've tried our simple ignition without timing advance with small glow2gas engine like .50. We are surprised until today that why no timing advance run better for both low and high speed, as well the transition from low to high. I would be glad if some one can explain. May be small engine does not need timing advance.

Thank you,

RE: DIY Ignition System - Most simple
 

It ran on gas. (Actually gas and lube mixed)

RE: DIY Ignition System - Most simple
 

Cleaner than glow? Oh yes, absolutely cleaner and lot cheaper fuel. You can think about how clean of power weed cutter, which may be alreay in your garage. It is gas engine and work the same way. (Gas version not electric)

I'm sorry that we don't sell, but we are happy to tell everything that you can make by yourself.

RE: DIY Ignition System - Most simple
 

Thanks Jezmo.

RE: DIY Ignition System - Most simple
 

Great work!!I am interested!! I'm new to gas so this may sound stupid but I see the plug you use is very small,is there one that small that fits into a glowplug recess without modification? What oil ratio do you use? What is the voltage range, current consumption and will it work on a single lipo? Whats the best coil that you have used?
I reckon it works like a magneto ignition system without the magneto. You trade off top rpm,easy starting and a little more vibration I think.But thats fine for small engines.

RE: DIY Ignition System - Most simple
 

Looks like a cool set up. Thanks for the info. Is there a smaller coil that you could use to save some weight?
Pete

RE: DIY Ignition System - Most simple
 

they use a spark plug with the same thread size. c&h sells the plug for 15.00

jezmo, twice i've inquired about doing this. they told me that it only works with large engine's (super tigers and big saito's) he said the carb needle is the problem, one click too rich, next click too lean. i wanted to convert saito .80 and then my magnum 160.
maybe i will try again about the twin. jeff

RE: DIY Ignition System - Most simple
 

Thank floks for question, comment and helping me to answer.
The plug I use was ordered from RIMFIRE here http://sparkplugs.morrisonandmarvin....cfm?menu=14-32
It is called 1/4-32 spark plug which its diameter and thread exactly the same size as glow plug. So you don't need to modify the head of the engine.
It run fine for all range from oil to gas ratio 1:10 to 1:5. I perfer thick oil because connecting rod is still bushing not needle ball bearing.
The system need 10-12 Volt power supply so it should work well with 3 cells Li-Po battery. I've not measured current consumption yet but for the next try I will.

And this is for patxipt, the circuit that uses simple switch.
http://www.rcthai.net/forum/attachme...1&d=1201827982