Vertical force balance

[Angel Rodriguez]

Dave and I have been working on 3d printed vertical force feed back that are easy to build and nearly as good as the metal Yumas. We have one that we made during COVID which we cal MOHO Pro and on that is still a work in progress that is called MOHO Explorer.  The Explorer uses a novel system to detect the position of the boom and the electronics only have two dual opamp.  I have attached four helis of a singel MOHO explorer, The upper left is the raw data, the lower left is a filter that I call microseism filter, you can see the peru quake the Vaunatua quake and a to other regional quakes, the upper right is the teleseismic filter and you can see the recent 7.3 even and the lower right is what I call the geophone mode.   On ther upper right, teleseismic mode you can see a long wave train at local time 23:30, that I suspect are the surface waves from the recent 7.3 quake circling the earth once.  I have also attached a picture and a CAD image.  I have kits for the MOHO Pro and plan to have kits for the Exploer once the design is a bit more stable.