Engine kill box design

[bobgroger]

Posting because we have EE's on board here, and I am not one although I was a tech for years. I can't see paying $200 for a box that kills your ignition for 50-100 milliseconds. The basic design seems quite simple, a 555 timer IC as a one-shot. Should be able to use a variable resistance to set the time period, driving a couple FETs to either ground the low side of the coils, or open the high side, for <$20. Wondering about the pros and cons of either. Will a Dyna-S module stand up to being grounded? Will opening the + to the coils or the Dyna cause a big backfire when it is reconnected? I am not after the last thousandth of ET by counting shifts and reducing the kill time, I just want my Air Shifter to work. Any ideas?

[posplayr]

Posting because we have EE's on board here, and I am not one although I was a tech for years. I can't see paying $200 for a box that kills your ignition for 50-100 milliseconds. The basic design seems quite simple, a 555 timer IC as a one-shot. Should be able to use a variable resistance to set the time period, driving a couple FETs to either ground the low side of the coils, or open the high side, for <$20. Wondering about the pros and cons of either. Will a Dyna-S module stand up to being grounded? Will opening the + to the coils or the Dyna cause a big backfire when it is reconnected? I am not after the last thousandth of ET by counting shifts and reducing the kill time, I just want my Air Shifter to work. Any ideas?

$5 parts,
$50 prototype board
$500 design time
$1000 integration and test.

[bobgroger]

There is some truth there, but you have done it with the SSPB. I don't intend to sell this, and it seems simple enough to generate a 50ms pulse. Ordered this for a test bed: http://www.ebay.com/itm/DC-12V-PWM-T...-/201429255367
Through hole construction makes it easy to change a couple components in the timing and it should be good. I will report back later.....

[posplayr]

There is some truth there, but you have done it with the SSPB.

Ask Rusty about "banging the bits".

BTB is way over complicating the problem, if you don't know what you are doing you just can't solve the problem efficiently. There is nothing complicated in the least about the problem, the same way there is no complication in "digging a hole" . The problem is that if you don't have a shovel that hole certainly got a lot harder to do. On the other hand a guy a backhoe, would not bother to start his machine to dig that hole in 5 minutes.

There is a guy that specializes in delivering holes(DynaTech), and if you don't have a shovel that is your best option.

http://www.thegsresources.com/_forum/showthread.php?221819-1st-generation-AUTO-cancel-TSCU-quot-banging-the-bits-quot&highlight=TSCU

BTW, it would be hard to conceive of a worse electronic solution than a 555 timer for msec level resolution timing. If you admit mechanical devices, an egg timer would be worse.

I cut my teeth in electronic circuit design developing airborne (highly efficient) circuits for waveform generation in EW applications (almost 40 years ago).