Beeping Spark Plug Tester

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
I have a tester that looks similar to this.

1st problem is, when I am pulling the cord on a lawmower, I'm too far away to see if it lights up or not.

2nd problem, I am usually pulling said rope during the day, when there is bright sunlight.

Is there a way to wire something inline that will beep if a spark occurs?

I have numerous small speakers, but I don't know if they could be used in such an application, and if they can, how would I go about wiring a speaker / beeper into this device.

Any suggestions appreciated.

Gary
 

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inwo

Joined Nov 7, 2013
2,419
I was thinking that the high voltage would trigger a strobe light. (I've been working on one):)

Then I thought, duh, that's an old school timing light. They are pretty bright and have a lens.

A little off from what you are asking.:p

I'm sure someone will have a HV trigger circuit for you.
 

Alec_t

Joined Sep 17, 2013
11,650
I'm sure someone will have a HV trigger circuit for you.
Using voltage as a trigger will indicate that high voltage is at the plug lead, but wouldn't necessarily indicate if the plug is sparking. The commercial unit presumbly responds to current flow in the lead?

Edit: Perhaps fix a photo-sensor next to the tester light and wrap the whole assembly to exclude ambient light. Then use the photo-sensor to trigger a beeper.
 
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Dr.killjoy

Joined Apr 28, 2013
1,196
You don't need some kind of fancy tool here .. All you need to do is pull the spark plug out and ground the plug against the block and tug on the cord a little and you should be able to see the spark... Whats wrong with the mower?????





Thanks
Jason Sr
 

#12

Joined Nov 30, 2010
18,210
If you don't have a cat that will cooperate, perhaps wire the inductive pickup to an ear plug. Look at post #4. If the pickup will drive a 1k resistor with enough leftover to drive a transistor, it will "click" in a high impedance earplug.

Inductive pickup = magnetic iron circuit with a coil wrapped around it, somewhere. Voltage = no response. Current = yes response. A voltage will be induced in the winding of the pickup. That voltage will make a high impedance speaker or piezo, "click".
 

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
I'll give the ear plug a try.

I tried taping an "On" inductive amplifier near the plug, but it didn't work.
I tried a cheaper Greenlee, AC detector, and nothing.

The mowers are many, I repair those I find by the roadside.
I got a nice Honda mower last weekend and had it running in a couple of hours.

The reach, and my inability to see well at distances cause issues.

I'm usually jerking on the cord, and the mower is moving around, and I have to hold down the Flywheel Lock Disengage handle, and etc.

I'm just being a little lazy.

I may try a long cord, wired into my Harbor Freight spark tester, and bring it back to the area where I'm pulling the cord, holding the handle, surely that will work.

I'm just fishing for ideas.

Thanks,
Gary
 

bwilliams60

Joined Nov 18, 2012
1,343

shortbus

Joined Sep 30, 2009
7,946
When I was a kid, I used one of my sisters. She held wire while I pulled. Lucky I had many sisters and few mowers.
 

inwo

Joined Nov 7, 2013
2,419
I believe this to be a good project.

I'm surprised that there hasn't been good circuits suggested by our simulators.:confused:

I 9v powered beeper that clips on the plug lead.

I think it would sell. (If loud enough for me to hear)
 

#12

Joined Nov 30, 2010
18,210
I think it would solve the Schrödinger problem. You don't have to look in the box if it's howling. :D
 

#12

Joined Nov 30, 2010
18,210
But, seriously, I have bought a timing light just to get the pickup from it. (Another method would be to look up the model number for the timing light and buy the pickup as a "repair part".) I used the pickup to build an automotive input for my scope. When I only need the timing light, I plug the pickup into it.
 

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
I was at Autozone last night getting wiper blades, and they had one like the Dezino art.com example. It's adjustable for different voltages, and you get to see the spark jump the gap. It was $7.00.

So I'm going to use that, with a long wire, and I should be able to see the spark (healthy or not, or non existant).

I still like the idea of a small attachable device for DC, like the AC Greenlee GT-11 Voltage detector, that requires no contact, but simply beeps loudly when near high DC voltages.

Thanks for the input, and if you invent said device, let me know.
If it's under $20.00 I'll buy one (and I'll bet you could sell a million of them in short order).

Thanks again,
Gary
 

Alec_t

Joined Sep 17, 2013
11,650
beeps loudly when near high DC voltages.
Fine so far as it goes, but probably won't detect an earth leakage fault or a cracked plug insulator (either of which could prevent the plug sparking).
 

inwo

Joined Nov 7, 2013
2,419
The fluke1AC-A works.

Not saying it's useful, just that holding it near my mower plug, it flashes each stroke. (not running, I just rolled it over)
 

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