Hacking a SX2 Mini mill

SX2/CN2 tachometer kit in action
SX2/CN2 tachometer kit in action

I picked up a SX2 Mini mill recently via Little Machine Shop (They call it the HiTorque Mini Mill 3900). When I received it, I noticed there was a port for a digital tachometer readout on the side of it. I though this might be useful, but felt 125$+ for it was a little excessive for what it was. Atop of this, they were out of stock.

I ended up reverse engineering the protocol, building some less expensive kits, and documented how exactly I figured out the protocol. Along the way, I also discovered how to make the mill run in reverse!

If you wondered how a reverse-engineering problem like this is approached or what tools are used, this could be an interesting read:

http://macpod.net/misc/sx2_tachometer/sx2_tachometer.php

CNC User Group Wrap-Up

We hosted our first CNC/Makerbot User Group meeting. A special thanks goes out to Brian Dolge for organizing the event and making it a success. We had a great turnout with about 20+ people in attendance. Marty McGuire demonstrated his Makerbot by drawing on Post-Its with a Sharpie. Harford Hackerspace demonstrated their CNC Milling machine by cutting out a wooden Ninja star. Check out the images below.