TetraLite Products
TetraProbe
An Low-cost Digitizing Probe for CNC Applications.
Home | Description | Performance | Order | Contact

Description, Connection and Operation

TetraProbe Specifications:

Overall Length (w/o stylus): 3.378"
Body Max. Diam.: 1.57"
Body Height: 1.25"
Arbor: 0.375" diam., 1.275" usable length
Stylus Center Adjustment: 3 places

What you need besides a CNC machine:

1. You will need a way to interface the probe to your computer. Most CNC controllers use the parallel (printer) port. This port has several inputs that can be used. Some controllers may have "breakouts" built in for connecting various types of inputs. Your CNC software should have a provision for assigning one of the inputs to be used for a digitizing probe. If you don't have a high-impedance input buffer already wired to an unused input, you can add one. You can't just wire the probe directly to a parallel port input because of the low impedance circuit it creates. It will work at first, but after a short time you will begin to get carbon deposits building up on the internal probe contact points. This raises the contact resistance and the probe stops working. The TetraProbe has a 1/8" miniature phone jack for making the connection to your interface. You will need to have a 1/8" miniature phone plug on the wire pair that plugs into the probe.

2. You will need to make or buy a stylus for the probe. The TetraProbe comes with your choice of either a 4mm or 5mm female threaded adapter for the stylus. Many styli are available commercially with 4mm x 0.7mm threads or 5mm x 0.8mm threads. A good source for styli is www.itpstyli.com. They have a large assortment of ruby tipped and other styli. If you make your own, you just have to put 4mm or 5mm threads on one end, depending on the adapter you order with the TetraProbe.

(under construction)