Heavily based on Matthew Ray's mouse trap, I really wanted a trap I could tell was occupied at a glance as I would have it set in the my porch most of the year round so I added a flag which pops up as soon as the inner door of the trap is lifted. This doesn't otherwise affect how the trap works.

Changes from the original

• pop-up flag clearly shows when a mouse has been caught
• added a secure latching lid with serpentine print-in-place spring to prevent accidental release when moving the trap
• corrected axle length on the front door and the seesaw for easier assembly
• resized to fit on smaller print beds (e.g. A1 Mini or Prusa Mini)

Features

• Pop-up catch indicator shows when trap is occupied at a glance
• self-resetting mechanism allows multiple mice to be caught in one night
• secure latching lid prevents escape/accidental release
• anti-nibble air holes

Printing

I printed this in PLA mostly with standard settings, there are a couple of recommendations however to ensure the mechanism works as intended - print the front door, short section of the seesaw and flag counterweight with 100% infill, using 15% infill everywhere else

Assembly

Cut away the tab from the underside of the box

From the underside, insert the front door. The pivot slots into the frontmost holes in the box

Insert the seesaw into the remaining holes

Turn the box the right side up and check that both front door and seesaw move freely.

Next, insert the flag at the rear of the box, and secure with the axle bolt

Install the inner door, aligning the short part of the pivot with the recess

Gently check the flag raises when the inner door is opened slightly

Add a drop of WD-40 or similar to the pictured end of the latch, this will make it much easier to retract

Add bate to the bate tray (peanut butter works well), put the lid on and ensure the flag is lowered. Your mouse trap is ready to go!