$90 plus shipping.
I modified an optical tachometer so that the optics is remote to the readout (with a 5.5 ft cord). This gives it much better versatility and greatly widen it's application. Now you can monitor any RPM you want by applying a piece of adhesive reflective tape to what you want to measure, mount the remote optical head to aim at the tape, and get an rpm readout.
Pic is rpm of the alternator, 4001 rpm at idle, on my Jetta. The reflective tape is on one fan blade on the alternator. A magnet is temporarily holding the remote optics to the alternator bracket.
Topic: F.S. really cool remote optical tachometer (Read 3271 times)
