If you don't want to mess with designing/building electronic circuits, you can easily adapt a General Motors "HEI" module to work for you. HEI=High Energy Ignition. It was used on literaly millions of mid 70's to mid 80's GM cars. It has semi intelligent coil dwell control, 4-5 amps of current limiting, and it is made for inductive pick ups, or reluctors.
It has 5 connections:
G = reluctor input
W = reluctor input
B = +12 volt logic supply
C = ignition coil (-) terminal
The metal base of the unit is the ground connection
The (+) terminal of the ignition coil goes to +12 volt supply.
I don't know what you are using this on but, you could probably use a GM reluctor made for the HEI and fabricate or use the GM magnetic star wheel.
These modules are commonly refered to as a "4 pin HEI module". Junkyards have tons of them for $1 or $2 each, new ones from a parts store are about $15.
The coil should have a low resistance primary of about 0.6 ohms. You could even salvage a GM coil while you get a module and reluctor.
Search for an MC3334, its an old IC that is the heart of the HEI module. I couldn't find a link, just a pdf to download, but it's out there. You can also search for HEI, you'll see many occurances of my "HEI mod" for Ford Probes and Mazda MX-6's.
The circuit shown in post #30 is promising.
Q1 is not a logic level mosfet so it will need quite a bit of reluctor voltage to fully turn it on (like 7v). The stack of 4001's help a lot but it may not be enough. To get a large reluctor output, you'll need a small gap to the magnet, a strong magnet, and/or a fast moving magnet. A Logic Level IRLxxxx might work better.
Q1/R2 only allows about 20ma of current to the base of Q2 and the resistor R3 across it. That's not alot. Make the R3 resistor across Q2's B-E as large as allowed to force more of that 20ma into Q2 to turn it on harder.
I forgot what I was going to say about Q3, it couldn't have been too important