Overall I’m pretty happy with my Longmill but I do feel that it should come with inductive homing and limit sensors as standard (and have no issue with the price reflecting that cost). Homing sensors are necessary in order to have stable repeatability.
HOMING SENSORS - HIGHLY RECOMMENDED
Homing sensors help the machine find machine 0,0,0 when it is first powered on, so you can always begin your work from a known location. I’m not a fan of the (cheaper) mechanical sensors as hitting them will eventually break them, it might break them quickly at high speed and then you’ve defeated the whole purpose.
Limit sensors help detect the approach of the end of the physical travel of the machine, so you can avoid crashing the machine - either during cutting or repositioning. Crashes are bad and can be dangerous. At ~$10/sensor for inductive ones, I consider it money well spent. When measured in wrecked work pieces, the sensor investment is tiny.
Technically you only need 3 sensors to home but for safety reasons you should have sensors on all axis max and min. Homing sensors are a subset of a complete limit sensor setup.
I made a suggestion almost a year ago that more thought should go in to sensor placement and also general adjustments to the design to improve accessory connection. I am hopeful that will appear in future revisions. In the mean time, I spent a substantial amount of my time and effort thinking, measuring, designing and making prototypes of a way to easily mount sensors to the Longmill.
WELL JUST 3D PRINT SOME!
If you have a 3D printer you can probably cobble something together, but I don’t have one and there are no ready mounting points in the foot designs for the Longmill. If sensor mounts are not built in to the machine itself, at least design files would be good that can be cut on the machine without requiring a 3D printer. Perhaps that is an option in the future, if including sensors isn’t in the product plan.
ENOUGH TALKIE TALKIE - SHOW ME VIDEO
So, for those who wanted to see what my setup looks like, here are a few videos. Please pardon the mess in the shop and the condition of the wasteboard. The wasteboard is about to be replaced and shows the scars of a year of learning.
YOUR WIRING LOOKS UGLY
I’m no expert at wiring and I didn’t solder my wires as I still consider my setup a work in progress. I use Wago 221 electrical connectors because they are very flexible and secure. I used a 10’ Cat5 ethernet patch cord with the ends snipped off for the signal lines and to carry 5V & GND from a simple USB wall power supply. I cut the end off a USB cable (not the end that plugs in the wall/power supply, left that so I can plug it in normally) and used a Wago 221 to connect the 5V and GND to the ethernet cable in the drag chain.
At the router, I used separate Wago 221 connectors for each of the signal lines on the machine side and at the XZ gantry.
Here is a video of where I ultimately put my sensors:
4 Port Relay for Noise Suppression: