Jon's Place

Friday, October 23, 2015

CNC Milling

As some of you probably remember, I have a Sherline CNC milling machine. It hasn't had much use in the last five years, but sometimes you really need to make robot parts out of metal instead of 3D printing them in plastic.
My Sherline CNC Mill
I needed some new parts machined for Seeker 2x, so I decided it was time to haul out my mill, and get it running again. The last time I used it, I was controlling it from an old laptop I bought in 2000 (a 1 GHz Pentium 3) using Mach 3 through the parallel port. I decided I wanted something a little more modern, so I started researching options. It turns out that the Xylotex control box I used was simply a power supply and a stepper control board to handle 3 axes, using the normal step/dir control pins for each axis.
Xylotex CNC 3-Axis Control Box
So, with a lot of research and discussions with my brother, I ended up installing GRBL on an Arduino Uno I had in one of my drawers. I wanted to use ChiliPeppr for my GUI, and since my desktop is on the other side of my office from the mill, I decided to use a Raspberry Pi 2 that I had to run the serial port json server, so it could sit over on the desk next to the mill, and give access to the mill over the network.
I soldered together a custom 7-wire cable to connect my Arduino to the stepper board, set up the Rpi with the server, and plugged everything in. Amazingly, it all works seamlessly. Next post will talk about the software I use to get from CAD models to G-Code.


Wednesday, October 14, 2015

Seeker 2x Running MicroPython

My new boards came in today, ordered from Dangerous Prototypes. I ordered the boards on October 6, and they arrived at my door on October 14, which is amazing. The best part was the cost, the boards (10 copies of one board) were $10, plus $20 for 2-day shipping. Definitely worth it.
Seeker 2x new PCB

The idea is I'm stripping all the old electronics out of Seeker 2x, and I'm going to be replacing the insides with this new board, which contains:


I always had big software plans for Seeker 2x, but I really don't like programming in C, so I never got around to actually doing more than a bare minimum. Now that I'll be able to use Python to code things, I'm hoping I can do some much more advanced tricks.
Seeker 2x
I'm also really excited to play with the new 9-axis IMU chip. For $16, you get a full nine-axis sensor package together with an onboard Cortex M0 ARM chip running real time (100 Hz) sensor fusion. A few years ago, that combination would have come on a big board and cost over $1000.