Welcome to my first Instructable. I made this Bluetooth tracker using a dead Tile tracker which was no longer under the reTile program. This is a quite simple build if you take a few hours. I don't have photos of enough sub-steps as I decided to make an Instructable after actually building the device. I also made only one tracker, not four.

DISCLAIMER: I am not in charge of the destruction of any good Tiles. That's why I suggest using a Tile with absolutely no practical use left.

Step 1: Materials and Tools

Materials

a Tile - I used a dead, irreTileabe Tile claimed at a convention.
5mm thick balsa wood - you might use 1mm for square pieces and skip the carving step.
white glue
rubber eraser - preferably hard eraser
stainless steel wire or paper clip (optional to make the tracker into a key ring)

Tools

sharp utility knife (you could also use a laser cutter to cut the wood)
flat screwdriver with black tip
ruler (even 30cm ones work)
pen

Step 2: Step 1: Disassemble and Reassemble Tile

As seen in the above picture, you first need to open the case. The two sides are grued to each other, the button cover's sides enclosing the other cover's sides, so you separate them using a sharp object like a flat screwdriver or a guitar pick. Then you remove the circuit board (PCB), then the battery glued on the PCB if it's dead. You can glue back a CR2032 battery instead of another CR2025 as they are a lot more common, but CR2032 is thicker and that's why we are making a new case. Also remove the piezoelectric buzzer (the round, brass colored thing) which is likely torn apart from the PCB during its removal. Align the black points on the brass pins on the board and tape it all together. Your Tile should work normally now - the button is on the under side of the PCB.

If it doesn't work, first check you can find your phone with it. If you can, try to reattach the buzzer and test if it makes sounds now. If you can't find the phone with the Tile, try reattaching the battery and make sure it presses on the battery connections of the board or try another battery. If you can't make the tracker work after trying these several times, check if any chips on the PCB are hot. If they are, there might be a short circuit or the battery is connected in reverse - fix them. If it still doesn't work, I can't think of any more fixes, you might have permanently burned a chip through your static electricity or some other voltage. In this case, I suggest buying a new tracker.

Step 3: Step 2: Assemble the Case

The case was planned to be friction fit to be made open-able. It didn't quite work, but it was good enough. Cut two 4cm * 4cm squares out of 5mm thick balsa wood. Cut two 4cm strips and stick them along two opposite edges of one of the squares, sticking them on their factory-sanded edges. Make sure the PCB fits in between - if not, thin the strips. Cut two more strips of the same thickness and adjust their length, so they fit snugly with slight friction in between the other strips (consult the first picture if you don't understand.) Close the box and sand to even out the edges. I also suggest rounding the corners if you can make it good.

Turn the flat sides of both covers up. Choose the one with denser fibers. Mark a rectangular area inside the chosen cover and make ~4mm deep slits along the sides of rectangle perpendicular to the fibers. Carefully carve between the slits, so that part of the cover is so thin that you can press into from outside - this will be the button of the tracker. Place a piece of eraser in the carved hole (it's a piece of wood in the second photo - I later changed it and it works better now.)

Step 4: Step 3: Final Assembly

Place the circuit board into the button cover, button pressing on the piece that acts as the piece. See if the other cover will press on the board from the other side - if it won't, fill in between using another eraser piece. I suggest securing the eraser pieces on the corresponding points on the PCB, so they don't slide and miss the button, for example. Close the case and test if the Tile works when you depress the thinned-out area - if not, try adjusting the thicknesses of eraser pieces or add more and make sure the big eraser piece actually presses on the button. Draw some decal - or the Tile logo - on the cover where the button is and well, you are done. You might also add a key ring attachment as seen on the project picture.