The mounting holes on Go Direct Sensor Carts are for attaching devices to the cart. We do not make any accessories that use these threaded holes at this time. You can use the holes for attaching accessories that you create. The measurements for the positions are shown in the image below. If you do something cool with these, please send us a message at innovate@vernier.com. We love to feature teacher’s creations in our posts.
The port labeled “ACCESSORY” is for future expansion on the cart. There are no accessories that make use of it at this time.