Upgrade Your Elegoo Phecda Laser Cutter with After-Market Limit Switches for Better Repeatability

Pseudonymous developer and self-described tinkerer "BadMonkey Edd," hereafter simply "Edd," has improved on Elegoo's Phecda laser-cutter design — by adding in after-market limit switches for more consistent homing.

"The Elegoo Phecda is a capable laser cutter, but lacks limit switches to allow consistent and automated homing, which in turn makes repeatability of cuts more difficult and/or time consuming," Edd explains. "By adding limit switches it improves the laser significantly."

Elegoo's Phecda is a low-cost desktop laser engraver and cutter, available for below $200 in its lower-power 10W variant, offering a 400×400mm (around 15.7×15.7) working area and an optional air assist add-on. It's capable of a 25,00mm per minute (around 984" per minute) engraving speed, boasts a smoke filtering exhaust, and can even handle cylindrical objects with a rotary axis add-on.

What it doesn't have, however, are limit switches — momentary switches that can detect when the X/Y gantry has reached either the limit of its movement or its home position. Without these, it can be tricky to have the laser positioned at exactly the right spot each time — which is where Edd's upgrade comes in.

Edd isn't the first to think that the Phecda could do with limit switches: his upgrade is based on a Creative Commons Attribution-ShareAlike-licensed 3D-printable switch holder published by the pseudonymous "SplinterPrinter" on Printables.

Edd's contribution is a detailed write-up of how the switches should be wired up and how to make use of them in both the LightBurn software and as an addition to generated G-code output. "It is possible to finish the commands with $H to automatically home the device when starting any job," Edd notes. "This would allow repeatability to jobs being run from SD cards with auto homing before the job starts."

The full write-up is available on Instructables, though comes with a warning: "Initially I tried configuring [LightBurn] using the Laser Tools->Machine Settings, but something happened and it 'permanently' set the machine to an invalid configuration," Edd says. "It took me quite a while to get back from that state. I think I fixed it by holding down the white button on the motherboard and turning on the machine, while continuing to hold the button down. I am not confident with what I did to break it, or fix it, so since getting the machine working again, I haven't tried again!"