Go Back   DIY Go Kart Forum > Building Plans And Advice > Electric Projects

Notices

Closed Thread
 
Thread Tools Display Modes
  #1  
Old 01-31-2011, 06:34 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default Electric Project Proposal (Challenge)

Howdy, y'all! (See, I am a Northern Redneck!

Anyhow, I've cooked a few braincells on the whole flywheel detonation thing. Some believe it, some don't. Doesn't really matter. Why? Other parts can fail. We all know (I hope) that it's a bad idea to free-rev an engine. But sometimes spit happens. Like a throttle sticking, throwing a chain, clutch failure, noobs riding your toys, whatever.

What I'm getting at here, is that I would very much like to see an electronic rev-limiter that can be applied to any one of our single-cylinder engines. It could be fixed to 5 or 6k RPM, or perhaps adjustable.

I know very well that there's a few of you around here that have a good understanding of electronic and IC circuitry. Surely one or more of you are capable of devising a basic electronic circuit capable of this. I don't know enough, but the concept seems clear:

Since the coil pulses once per revolution, all the circuit has to do is count pulses over time. If that count tries to exceed a predetermined number over a set time, the circuit grounds out the coil, disabling the spark until the RPM drop below that specified number.

This is not to debate whether it's necessary- This is to see if someone here can pull it off... Any takers? Kibble? Russ? Anybody else here know their way around a PCB?

Think about it- a little piece of mind for some, and they'd sell like frigging hotcakes to all the panic-prone masses!!!
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #2  
Old 01-31-2011, 06:37 PM
devino246's Avatar
devino246 devino246 is offline
Official DIYGK Chem Nerd
 
Join Date: Sep 2009
Location: Lynchburg, VA
Posts: 3,856
Thanks: 270
Thanked 283 Times in 244 Posts
Default

Quote:
Originally Posted by toystory_4wd View Post
Howdy, y'all! (See, I am a Northern Redneck!
I take offense. I say yall. This is a redneck:
Attached Thumbnails
38087630002_large.jpg   united-states-redneck-special-forces.jpg  

__________________
ASE Certified
  #3  
Old 01-31-2011, 06:39 PM
devino246's Avatar
devino246 devino246 is offline
Official DIYGK Chem Nerd
 
Join Date: Sep 2009
Location: Lynchburg, VA
Posts: 3,856
Thanks: 270
Thanked 283 Times in 244 Posts
Default

Now that Im done with that... Wouldnt grounding the coil & cutting the spark cause an excess of fuel to accumulate in the combustion chamber?
__________________
ASE Certified
  #4  
Old 01-31-2011, 06:53 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

Probably. And when the ignition cuts back in, it'll burn off. Try kitting your kill at WOT, then turning back on before the engine comes to a stop.

And I'm PROUD to be a Northern Redneck!!!

Come to think of it, it'll just blow out the exhaust.
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #5  
Old 01-31-2011, 06:55 PM
devino246's Avatar
devino246 devino246 is offline
Official DIYGK Chem Nerd
 
Join Date: Sep 2009
Location: Lynchburg, VA
Posts: 3,856
Thanks: 270
Thanked 283 Times in 244 Posts
Default

Quote:
Originally Posted by toystory_4wd View Post
Probably. And when the ignition cuts back in, it'll burn off. Try kitting your kill at WOT, then turning back on before the engine comes to a stop.

And I'm PROUD to be a Northern Redneck!!!
Actually, thats true.

Once again, yall does not equal redneck. Cherrybomb=redneck.
__________________
ASE Certified
  #6  
Old 01-31-2011, 06:57 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

What're y'all sayin' 'bout my Cherry Bomb?
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #7  
Old 01-31-2011, 06:59 PM
devino246's Avatar
devino246 devino246 is offline
Official DIYGK Chem Nerd
 
Join Date: Sep 2009
Location: Lynchburg, VA
Posts: 3,856
Thanks: 270
Thanked 283 Times in 244 Posts
Default

Quote:
Originally Posted by toystory_4wd View Post
What're y'all sayin' 'bout my Cherry Bomb?
__________________
ASE Certified
  #8  
Old 01-31-2011, 07:08 PM
kibble's Avatar
kibble kibble is offline
I banned myself
 
Join Date: Mar 2007
Posts: 2,766
Thanks: 35
Thanked 129 Times in 114 Posts
Default

__________________
"At the enrichment center we believe that if at first you don't succeed, you fail." GLaDOS - Portal
The Following User Says Thank You to kibble For This Useful Post:
Doc Sprocket (01-31-2011)
  #9  
Old 01-31-2011, 07:10 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

Excellent! Thank you!!!
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #10  
Old 01-31-2011, 07:17 PM
kibble's Avatar
kibble kibble is offline
I banned myself
 
Join Date: Mar 2007
Posts: 2,766
Thanks: 35
Thanked 129 Times in 114 Posts
Default

Oh, you mean you actually thought I was gonna try to do this? Nah, I was just trying to be funny.

JK wit ya Yes, I'll give it a shot. I actually started getting some ideas as you were describing the requirements.
__________________
"At the enrichment center we believe that if at first you don't succeed, you fail." GLaDOS - Portal
  #11  
Old 01-31-2011, 07:23 PM
Bluethunder3320's Avatar
Bluethunder3320 Bluethunder3320 is offline
Senior Member
 
Join Date: Sep 2010
Posts: 5,677
Thanks: 516
Thanked 188 Times in 168 Posts
Default

great idea!!!! i cant wait to see what happens!
  #12  
Old 01-31-2011, 07:25 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

Terrific- I know a bit about electronics, not a lot. But from what I do know, I think it could be pretty simple. I'd just like a "failsafe" mechanism...
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #13  
Old 01-31-2011, 07:38 PM
kibble's Avatar
kibble kibble is offline
I banned myself
 
Join Date: Mar 2007
Posts: 2,766
Thanks: 35
Thanked 129 Times in 114 Posts
Default

Well, here's what I'm thinking about so far:

Have a wire, something a bit stiff, that you can wrap around the wire between the coil and the plug; this will be the pickup wire. Have that wire go into an OP amp that will sense the voltage difference between a preset voltage point and the voltage generated when the coil fires. The preset point will be adjustable so that there can be some control over the sensitivity of the pickup wire. The output of the OP amp will be driven into a microcontroller that will count the pulses from the OP amp and compare them against a preset amount. What will be used to compare the limit is yet to be determined. I'm thinking a set of dip switches that you can set to any value within the allowed range.

I'm thinking of even including a set of numeric LED's that will display the RPM value. The hardware aspect shouldn't be too difficult. Programming the IC will be the hardest part, although I don't think it should be extremely daunting.
__________________
"At the enrichment center we believe that if at first you don't succeed, you fail." GLaDOS - Portal
  #14  
Old 01-31-2011, 07:43 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

Kibble, you ARE my hero. Seriously.
Okay- but my point is, you definately understand what I'm driving at, and from where I stand, you look like you can pull it off. I've been thinking about this concept for quite some time. I'd love to see it materialize.
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #15  
Old 01-31-2011, 08:02 PM
Bluethunder3320's Avatar
Bluethunder3320 Bluethunder3320 is offline
Senior Member
 
Join Date: Sep 2010
Posts: 5,677
Thanks: 516
Thanked 188 Times in 168 Posts
Default

You lost me at "have a wire"
  #16  
Old 02-01-2011, 12:53 AM
dan's Avatar
dan dan is offline
Senior Member
 
Join Date: Feb 2009
Location: Austraila
Posts: 330
Thanks: 0
Thanked 4 Times in 4 Posts
Default

bahahaha @ ^^^^^, nar this will be awesome will love to see it wen its done
__________________
Alcohol: is for drinking. fuel: is for washing parts in. nitromethane: is for running engines on.
  #17  
Old 02-01-2011, 06:17 AM
sideways's Avatar
sideways sideways is offline
Unfinished projects king.
 
Join Date: Feb 2009
Location: Perth, Western Australia
Posts: 1,501
Thanks: 50
Thanked 163 Times in 115 Posts
Default

Adapt an after market car tacho to your engine in the way that has been shown on destructibles (or maybe it was another site?) and wire it so the shift light trips a relay that acts as a kill switch (ie, grounds the spark) and have a normal kill switch wired in parallel with it.

Of course, you'd need a charging coil or a battery that you are willing to charge all the time.

Thanks

Hayden
  #18  
Old 02-01-2011, 01:50 PM
dan's Avatar
dan dan is offline
Senior Member
 
Join Date: Feb 2009
Location: Austraila
Posts: 330
Thanks: 0
Thanked 4 Times in 4 Posts
Default

Quote:
Originally Posted by sideways View Post
Adapt an after market car tacho to your engine in the way that has been shown on destructibles (or maybe it was another site?) and wire it so the shift light trips a relay that acts as a kill switch (ie, grounds the spark) and have a normal kill switch wired in parallel with it.

Of course, you'd need a charging coil or a battery that you are willing to charge all the time.

Thanks

Hayden
could you find that site were it shows you how to do it please?
__________________
Alcohol: is for drinking. fuel: is for washing parts in. nitromethane: is for running engines on.
  #19  
Old 02-01-2011, 03:44 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
*********
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,677
Thanks: 723
Thanked 2,202 Times in 1,692 Posts
Default

Quote:
Originally Posted by sideways View Post
Adapt an after market car tacho to your engine in the way that has been shown on destructibles (or maybe it was another site?) and wire it so the shift light trips a relay that acts as a kill switch (ie, grounds the spark) and have a normal kill switch wired in parallel with it.

Of course, you'd need a charging coil or a battery that you are willing to charge all the time.

Thanks

Hayden
I had exactly that thought, too- But I would like to see a nice, compact module that could ultimately be mass produced.
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...
  #20  
Old 02-01-2011, 04:07 PM
kibble's Avatar
kibble kibble is offline
I banned myself
 
Join Date: Mar 2007
Posts: 2,766
Thanks: 35
Thanked 129 Times in 114 Posts
Default

Good news! I was just playing around with the input part of the circuit and it works! Obviously you can't see it working in the pic, but the yellow wire is wrapped around the plug wire and the voltage induced when it fires is high enough to be amplified by the OP amp. I have an LED on the breadboard that lights up when the coil fires. I tested it out just a few minutes ago and it works great!

I need to test it out with an engine I can bring to my workbench so I can use my scope on it to make sure the pulses coming from the chip are wide enough and if not, then adjust resistor values accordingly.

__________________
"At the enrichment center we believe that if at first you don't succeed, you fail." GLaDOS - Portal
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 12:22 PM.