Running Koppi's Toy Bipod

Spot on Andy! The easy driver boards I am using apparently need to have the MS1 and MS2 terminals grounded to ensure they are not interpreted as HIGH. Anyhow all seems to be working now, I'm pretty stoked!

Got the bipod setup on a big board now and am ready to draw some stuff. Here's a couple videos of the first pattern from the new machine.

I have implemented a homing system into the machine using limit switched triggered from beads


It works well but there is a problem with the homing as it tends to set the machine in the +y rather than the -y area. How I have the machine configured is that 0,0 is on the left hand motor and the x position of the right hand motor is supplied in the hal. I'm guessing that the kinematics could be changed to force the machine to solve for the -y position always (it will never go above 0 since the machine is hanging under gravity).

A work around is to power off the motors and run a program which drives the machine into -y. Then when re-homing the correct -y home is found. I'm not sure why this works but wold be really interested in an explanation.

Does anyone know if changing the kinematics is the correct path, or have any ideas how to get the machine to home in -y every time? I am using the kinematics from here Koppi's Toy Git

chojin, are you willing to share your project files (hal, ini)? I'm setting up a similar bipod project to yours and I think I understand the kinematics but I'm struggling to setup my linuxcnc project. Thanks!

Yep the source files for the project are shared here github.com/Chojins/LinuxCNC-Polargraph

I also added control for a servo which can lift the pen which is pretty handy.

Thanks!