Handheld wand for the SparkFun 2D Barcode Scanner Breakout

I built this for the vinyl-cataloguing station: the half of the collection that never made it into Discogs needed a scanner that didn't involve holding a phone over a sleeve and waiting. This is a wand: lens out the front, a 45 mm hollow handle that swallows the USB-C plug, cable out a notch in the back, and a thumb button on top that presses the SCAN switch through a living hinge printed into the lid.

Print

Both parts flat as exported, 0.2 mm layers, no supports. The lid prints outer face down so the hinge web's extrusion lines run in-plane, which is what a flexure wants. PLA is fine; the button strain at full travel is about 0.8 %, comfortably under the PLA budget.

Hardware

• 4× M3 heat-set inserts (Ø4.0 × 5.7 mm)

• 4× M3 × 20 countersunk (flat-head) screws

• SparkFun 2D Barcode Scanner Breakout (BOB-18088) + a USB-C cable

Assembly

1. Heat-set the inserts into the lid posts.

2. Drop the board into the bottom shell lens-end first — it rests on the side ledges and the two front bosses, and the DE2120 module hangs in the front cavity with the lens flush to the window. Route the FFC through the board's slot at the gap in the ledge.

3. Plug in the USB-C cable, lay the plug in the handle, cable out the rear notch.

4. Fit the lid — the lip on the bottom shell seats in the lid's rabbet.

5. Four M3 × 20 screws from below: two through the board's own 4-40 holes, two in the handle. Countersinks are in the floor.

Nobody trained the cat to read. It simply started bringing things back with the labels facing up: a jar, a book, a record sleeve, dropped at the foot of the bed with the sort of expectant look that means you're welcome. It learned the little black squares before it learned its own name. It never learned its own name.

Point it at the thing you want known. Press its head. It chirps once, and the thing is known.