Software de controlo e plataforma giratória de fotogrametria

Photogrammetry has the great advantage to get impressive 3D models from real objects, capture their textures and colors as detailed as you want, and can be used with a common camera (or better a professional one like DSLR). Lasers instead are only used for 3d scanning and are limited to the capabilities of each product.

This project consists in a motorized turntable design to do semi-automatized photogrammetry, using a microcontroller like ESP32/Arduino, or a Raspberry Pi instead, and a software to control everything.
Is intended to use it with a DSLR camera to accomplish professional results, but it must work with other type of cameras (don't recommend it for professional results).

The exclusive software made by me allows you to configure and control the microcontroller (that controls the step motor), and the camera via USB, so it will take the number of set photos and turn the platform every time automatically, waiting times, save the photos into the SD card/PC*, etc. So you only have to wait to finish a full turn to change the angle of the camera or the orientation of the piece and do a new sequence.

The project includes:

• Set of STL's to do a basic turntable with a worm screw mechanism. This principle allows the motor to move the platform, but not the platform turn freely, so any undesired movement will be avoided. The base of the platform has leveling screws, predrilled holes to fit an ESP32 microcontroller and a expansion board for A4988 chip, and has slotted holes to fit other size of bearing cases instead of the default included (for cheap 2 x 608zz). The for the step motor is for a NEMA17 but can be updated for a stronger motor like NEMA23.

• Multiplatform program (Windows & Linux for the moment, and special Raspberry Pi version coming soon) that can flash your brand new microcontroller with the binaries for an ESP32 (not used in a RPi), so you don't need to install and struggle with anything else (like Arduino IDE). And then control the step motor of the platform and the triggering of the most cameras.

• Drivers for ESP32 microcontroller on Windows.

• Detailed instructions for printing, mounting the parts, links for buying components, and the use of the program.

• Assembling diagram to see clearly the parts how are assembled.

• Document explaining the tips to do an almost perfect photogrammetry sessions (void technique), and some resources to expand the knowledge of it.

• Document explaining communication's protocol between my program and the microcontroller (nedless for a RaspberryPi or if you follow the same components that I used), if you want to create new sketches with Arduino IDE to use it with other microcontrollers.

If you buy the project you will have:

• Private communication to resolve doubts

• Access to future updates

• Ask for custom pieces

To do the project you will need apart:

• A camera (and usb cable)
• A tripod
• A NEMA17 step motor (the project could hold up to NEMA23 updating a new motor mount)
• An AC/DC 12V power source
• An ESP32 microcontroller and USB cable (or Arduino, Raspberry Pi...)
• A few screws, nuts, 2x608zz bearings, and a few dupont jumper wires.

Note: The subprograms used to control cameras might have limitations on some cameras. For example, in windows with a Nikon D3500 it only allows me to save the photos in the PC. The subprogram used in Linux is more flexible.

Note 2: if you want a more robust turntable I recommend you to do the chasis in metal, and print only the worm screw, the helicoidal gear, and maybe the dish (you will have to buy some type of UCF bearing too). Anyway, the default turntable it can manage serveral kg.

Note 3: Gif setup is only for demonstration purposes. Read the Tips for photogrammetry document included in this project for professional results, using void techninque, that requieres a black background and direct light.

TEASER video, showing the system working:
https://www.youtube.com/watch?v=ZEo1--rNWpc

All parts are intended to print without raft. The STL's are already oriented in the appropriate printing position, excepting the platform base (PF-04) must be oriented 45º to fit printing area. A bed of 250×250 mm is minimum required for this reference.

To avoid possible warping or detachment of the piece, use adhesion lacquer. To detach and clean the plate use isopropyl alcohol or ethyl alcohol.

To do the void technique, it is preferable to use matte black filament. If this is not possible, all parts should be painted matte black, except the leveling threads.

VERY IMPORTANT: STL files are calculated with their exact dimensions. You must know your printer's error margin to scale the parts in the Slicer and correct the error. In my case, using a CR-10 V3, I had to scale the parts to 100.39% on all 3 axes to obtain an error margin of less than 0.15 mm. If your printer has already ed calibration tests, this should be sufficient. Discard the base measurements due to the elephant's foot effect. Do not print the whole set at once. Try to print some references initially to see the fit of the pieces. A margin of error of 0.1 mm per axis is considered.

To the project, PLA 850 1,75 mm was used, using this parameters:

• Nozzle: 0,4 mm
• Extruder: 215 ºC
• Bed: 40 ºC