[Travis] sent in his oh so simple(why didn’t I think of that) syringe logic probe. that he put together for his version of the sump logic analyzer. Real probes tend to be pretty expensive. With some effort, you can probably fit an led/diode/resistor in there and make a simple 5v logic probe. If you’d like a nice logic analyzer, Spartan-3 board that it’s based on is only $99.