My dad built one with an electromagnetic coil many years ago, can't find the design, capacity was limited but had 100? microgram resolution, maybe similar to th

My dad built one with an electromagnetic coil many years ago, can't find the design, capacity was limited but had 100? microgram resolution, maybe similar to this applied science video https://www.youtube.com/watch?v=ta7nlkI5K5g https://www.youtube.com/watch?v=ta7nlkI5K5g but I think simpler. maybe something like this: https://www.erowid.org/archive/rhodium/chemistry/equipment/scale.html https://www.erowid.org/archive/rhodium/chemistry/equipment/s... https://www.erowid.org/archive/rhodium/chemistry/equipment/scale2.html https://www.erowid.org/archive/rhodium/chemistry/equipment/s... I found some old emails about the scale from 2005/6 but can't find the link and it would probably be gone anyways.