Scanning one face of a 2 Dollar coin at a 0.15 mm grid resolution, it took about 8 hours to scan and about 42,000 points.
The precision of the probe is remarkable considering it is a DIY using some washers, soldered on a prototype PCB board, and a sewing needle for the touch probe.
To put in perspective the height of the letters on the coin are ~ 0.048 mm (that's 1 mm / 21)
This is on a DIY 3D printer, with Duet WiFi. I made a program in C++ that controls the 3D printer through Telnet over WiFi. The program exports an XYZ file, and also an STL file.
Here's a video with it in action: https://youtu.be/9lPobTaEvIE
Not sure when I will scan the other side of the coin...