Measure car engine speed RPM via the cigarette lighter

I setup my new oscilloscope to measure a car's engine speed by connecting to the cigarette lighter.  The inductive kicks from the ignition coil provide a timing signal that can be used to calculate RPM.  In this particular car (a DeLorean), the engine fires unevenly by design, so the inductive kicks are not all regularly spaced.
http://en.wikipedia.org/wiki/V6_engine

http://ranwhenparked.net/2010/09/14/what-lies-beneath-the-controversial-prv-engine-part-3/

Diffusion pump giveaway contest - ends May 31 2014

I'd like to send this diffusion pump to someone who can make good use of it.  If you are interested, please send me an email (500 words or less), or post a video (2 minutes of less) explaining what interests you about high vacuum, and what you plan to do with the pump.  I'm especially interested in folks who regularly blog or make videos about their work.

The contest will end on May 31 2014.  The order in which I receive the submissions is not important.

I may not respond to all submissions, and my decision will be final.

You will assume all liabilities and risks involved with using this equipment.  Once I send it to you, you will own it completely.

ben.krasnow@gmail.com

Unusual usage (hours) counter with mercury capillary

This is a usage counter that works by moving mercury in a capillary tube via electrochemistry.  As electricity flows through the device, mercury atoms are transferred across an electrolyte gap in the capillary. The position of the gap changes as mercury is transferred, and shows how much total charge has been passed through the device.


I realize that the divider network looks more like 20:1.  This might kill my theory that the mercury ions are in the 2+ state.  I'm really not sure.