Effeciency of Gear Tooth Sensor

[magical hands]

I have gear tooth sensors installed. so to test what i did is took a sprocket and placed it on a drill bill and i started spinning hte drill. than i took the gear tooth sensor and placed it near the moving sprocket but i found out that its not very effecient. Like it took so long to count and it has to be so close that it was hard for my hands to hold that close and often it sprocket teeths would touch the magnet.

For optimum results, anyone has any tricks or ideas that they want to share for accurate gear counts? By the way i was using the Kevin's encoder code with a bit of modification.