I previously have posted regarding this topic and got quite a few good suggestions as to the way to go. It appears the Renishaw style use an infrared transmitter, however several people have suggested useing an radio
transmitter to send out the signal.
Al_the_man, if you are out there, you mentioned you might have circuits somewhere for a simple transmitter/receiver?
Is anyone aware of a transmitter/reciever that could be purchased off the shelf and incorporated into a probe?
By the way, I found a commercially available switch with 1 micron repeatability for around $180 that could be used in both a probe and tool setter.