## 2 Materials and Methods
### CAD Design of the Prototype
The user, while manually sliding the arm holder, performs a sliding motion of the linear bearing, and at the same time, the motion is guided in the guide groove from one end position to the other end position. In the first position, the arm holder is moved to the front end position in the direction toward the laser projector, as can be seen in Figure 4a. Within this position, calibration is performed. Within the software, the OpenCV 4.7.0 libraries [18] were used to calibrate the device. Once the calibration has been performed, the user moves the arm holder to the other end position away from the laser projector, as can be seen in Figure 4b, with the camera arms folded down. Within this change in position, a change in the external parameters of the device is performed. In this position, the device can be moved into areas of difficult access. Once in the hard-to-reach area, the arm holder can be moved to the forward position to return the device to its position during calibration. This will return the values of the external parameters of the device to the values during calibration. A component was attached to the front end to allow eccentric attachment of the elastic cord along with the laser projector mount. To perform the translation of the projected laser pattern during the digitization process, the user rotates the guide rod. When rotating clockwise, the projected laser pattern is shifted to the right, and when rotating counterclockwise, the laser pattern is shifted to the left. This can be observed in Figure 5. The laser is mounted in the laser projector holder, which is held in the front mount by screw M3. A hole is designed in the front bracket for a screw with a slightly larger diameter to allow the screw to rotate and not be firmly attached. PTFE tape was wound onto the screw to flatten the thread surface and reduce friction between the screw and the holder. A small spring was  
Figure 4: Representation of the mechanism movement of the prototype device. **(a)** First device position during calibration and digitizing. **(b)** Second position of the device for insertion into confined spaces. inserted between the laser projector mount and the front mount to ensure the screw head was pressed against the mount. Once the laser mount was assembled, a thin elastic string was tied to the eccentric component on the guide rod. Initially, a slotted mechanism was designed to rotate and move the laser projector, but the components were designed to be very thin, with a thickness of cca. 2 mm. Some of these parts could not be manufactured by FFF technology to the required quality and strength, and some were quickly broken when the mechanism was assembled. For this reason, an elastic cord was chosen to carry out the movement, as can be seen in Figure 6. Once the assembly was assembled, this solution performed the movement correctly. The use of an elastic string also has the advantage of dampening unwanted collisions of the laser projector with surrounding objects during the placement of the device within confined spaces. The prototype digitizing device can be placed on a tripod. The device is designed to be powered by portable external power source via USB interface. This makes the device portable and does not need power from the grid. As can be seen from the power consumption measurements of the devices, one ESP32-CAM device consumes 270 mA during high-power function when transmitting high-resolution video. During digitizing, only video images are captured, and the device consumes roughly half of this power. The laser projector is rated 10 mW, while consuming roughly 2 mA when powered at 5 V. The maximum theoretical consumption of the device is 560 mA. When powered by a portable  
Figure 5: Representation of the movement of the laser line during digitizing. (**a**) Left position. (**b**) Center position. (**c**) Right position. Figure 6: Picture of prototype digitizing device. (**a**) At angle view. (**b**) At angle bottom view.