Ok Rob.. I'll try the caps and regulator once more with a 6 volt battery pack, and see what that does for the problem.. I agree the lower voltage does make the chip malfunction at times. On the old timer boards, I used that misfire to indicate when the battery was low. Maybe this one is more sensitive? Could be I guess, since it's being used differently with multiple functions accessed. Thanks!..... I'll give it a try.

John

Rob, the only thing I haven't done yet was to make a double sided PCB for the circuit. I tried the regulator and all the caps..still the same glitch. I even tried an Infrared Opto device as the trigger and it still does it. What happens is when I bring the magnet to the hall effect for the first time, it doesn't do anything, but the second time I do it, there are two sparks in a very short time. If I continue flagging the magnet past the hall, it starts an oscillation even though I pull the magnet away, so it is self triggering. Sometimes when I power up, without the hall connected, it does this also. At any rpm above 1100 rpms, it functions normally and will run my test engine fine. It's really tough getting it started though with the multiple sparks happening when I flip the prop cause it will backfire and quit.

I am wondering if anyone else who has built the system is having similar problems..seems like you and I are the only ones who built and tested it so far.

John

Hi John,

The problem, somewhere you pickup (HV) *noise* from the sparkcap / sparkcoil / HV-coil.
Have you placed a 100nF capacitor right between pin 5 and 14 of the pic at the bottom of the PCB ?
Dont'forget to connect both sides to eachother, top and bottom.
Twist all wires and keep them short.

If you get also firingup without the hallsensor, that's allmost imposible.
A resistor hold the input high, only a hard low signal can make a output signal.

BTW-1, the CDI can't given a spark the first time becourse it have first calc the rotationtime.
If the rotationtime is less the advangetime (-/+1000rpm) the CDI is given a spark started where you set the easy start.

BTW-2, do you set CW or CCW right ?

Rob, I have that cap on pins 5 and 14. It even does it with just the seperate timer board without the HV board plugged in. I watch the LED and it blinks twice for every pass after it senses rpm. After 1100 rpms it goes away. Oh well..I'll have to let it rest. I do have the CCW setting correct for my engine rotation. Maybe I have to send you my board so you can see what it does for yourself.. All my new timer boards do exactly the same thing. I can't see any mistakes on the boards..they all function well above 1100 rpm, including advance angles as I have set in the table. I think Iura has the same problem as I do.

John

Charlie, I can reproduce the bug.
The duble puls will be generate only below 46rpm.
Into the first rotation we calculate the time one rotation will take.
We have to do calculate this rotationtime for the advange timingtable if the engine runs <915rpm.
If after the first rotation no secondrotationtime will be make, the cdi produce the lost puls.
This is happend when you start your engine by hand, you can't run the engine by hand higher then 46rpm constant.
The programmer know this bug now and I hope he can fix this bug soon.

Thanks Rob... I figured if anyone could find it, you could!
I'm starting to figure out a board for the HV #3 schematic. Looks promising so far..wound the toroid for it and have all the parts. The DC-dc converter chip is small. should make it really simple to build.

John

Today we test the new PIC-version.
For now it looks good, no dubble puses anymore.
Also the puls into the first rotation is back.
You can start your engine with the first kick.

Excellent work Rob! I was hoping for that result.
Let us know when the hex file is available for download.. I have a dozen pics to program with the new changes.

John

I found a other problem.
Not into the PIC or electronics, but from the magnet.
The ignitionpoint isn't there where the program set this point.
If we set the point to 40 degrees BTDC, it's possible the real point of pickup will be 60 degrees.
The magneticfeeld disturb the real point and the point 20 or more degrees BTDC.
The picture shows wat happens if we turn the magnet 90 degrees.
With a magnet rotate 90 degrees, the trickerpoint will be exact the pickuppoint set into the program.
You have to turn the magnet 180 degrees if the rotation direction isn't CW.

Mine won't trigger the timer if I turn the magnet 90 degrees Rob. I am using a rare earth magnet from Radio Shack which I have been using for all other setups. I always use the south pole of the magnet to trigger the board.

John

which one is correct left figure or right ?

Both are correct, only the left picture will given youa spark at the time you have set into the programm to Pickup position BTDC.
It can also be done with a metal hull.
If you don't place the 90 degrees or use the hull, the pickup position can be 20 degrees or more wrong.

Thank Rob,

For those who are interested in more Hall effect understanding an good applications guide:

http://www.allegromicro.com/en/Produ...cations-guide/

Dino

Still seeking for areasonable source of e core ferrite [&o]

Rob,
I have used hall effect switches before and by noting the influence of the magnet i.e flux density, have managed to get simple ignition circuits to work quite well using the small round rare earth magnets (3 mm dia x 1.5mm thick)
I noticed previously you made mention of the optical devices and these I have also made good use of (because of their consistency and accuracy) in other machines for limit switches. Found they are consistant and accurate to within 0.001 inch so do you consider their use here would be benificial?
Cheers ...Jeff

If you know the distance the hallsensor is switching befor the magnet, there is no problem to use a hallsensor.
Calculate this time within the Ignition Pulse Width time and you have the right time for ignition.
(BTW, this is not correct because the speed of rotation change the magnaeticfeeld and time)
BUT, if you get backslash, the prop is pending between compression, the CDI is firing even if it's turn the wrong way.
When you turn the magnet 90 degrees (left picture), the problem is solved and even with backslash the CDI isn't firing.
Opto's can be durty from pertol or by landing into a plane and also on boats and cars you can get trouble with them.

Yes, had the same results before with hall effect.
So only problem you see with optics is the effect from dirty environment. OK ...thanks

maybe seeing flux will help......

I think we all using neodeen magnets, the flux is much bigger of this kind of magnets.
When reading the link of Dino, I think we can reduce the flux with a small magnet at the back of the hallsensor.
At the moment I can't test, we are very bussy to test a new version of the software.

Hi Rob..
How's the testing of the new software going? I tried the opto sensor devices I have here with the new timer board with exactly the same results I was getting before..so it's not the hall sensors or the magnets. The trigger source is not really the problem here but how the PIC sees it and responds to it. Something in the PIC software seems to be causing it. Without knowing what the software is doing in the PIC is making it hard to figure it out. I built another timer board with a newly programmed chip and it does the same thing. After it fires for the 2nd or 3rd time, it will go into some sort of an oscillation where it continually fires for a few seconds by itself for some reason.

Although the first change that was made does allow it to fire on the first revolution, the rest hasn't changed. Hopefully the programmer can find this and make the proper changes. I know it's difficult making changes and testing them while adding other features. Two other people in my area have just completed the timer with the same results. I have no idea how to write software or I'd have tried it. I appreciate what the programmer has given us so far and I'm sure he will figure this out, given enough time.[sm=47_47.gif]

John

We know the problem and work hard to solved it, but it takes time.
I test allready 4 other versions, but we don't know where we have to look.
Stranges enough into a simulator there is no error........
Can you test only the timerboard without the HV-part ?
BTW, settings for Igniton Pulse Width must be ~100usec

Rob, I'll test my seperate timer board I just built without the HV board connected...and I'll set the pulse width to 100usec as you suggest.

When I watch the LED it should show me when it goes into oscillation, also the spikes on the computer screen will show it has fired at about 4000 rpms. When it did it before, the timing advance jumped to max advance and back to 6 degrees.

John

Rob..
I tested the timer board with the second version of the software and no HV board plugged into it. The results were the same. It fires on the first pass, then the 3rd pass it fires twice. After that at any time it will go into oscillation and fire at 10,000 rpm as I saw it on the computer screen. The spike appears and then when it stops, returns to normal firing for a few passes and does it again. I also tried it with the opto device replacing the hall effect with the same result.

As I changed over to my auto firing module (3000 rpm constant), the timer board functions perfectly, so it is only at a low rpm that it misfires and oscillates. That makes it extremely difficult to hand start my engine if it starts at all. Hope this test result will help for the programmer to see what is happening at low rpms.

John

Rob..
I'm in the process of installing new software and hex file for testing the timer board. Results as soon as I get it working.

John

Looked at diagram of 16F628A and they show Rx and Tx pins as RB1(7)Rx and RB2(8)Tx which is opposite to your circuit.
Also wondering if unused pins should be tied somewhere instead of being left floating.
Read somewhere that a problem with unusual switching was resolved by grounding of PGM pin or by disabling in the program.(LVPDIS)
Don't do any programming so I cannot comment, just something I read and thought it might help. Cheers...Jeff

@Jeff, anything helps and trying can't hurt.

Next week I'm on vacation, no testing, no electronic, no CDI [8D]

Nice weather, 12 degrees with a lot of sun.....not bad at all

BTW, I'm the one on the left.....