Fixing a bicycle computer in the middle of nowhere

As a result of a thorough security check at FRA airport, the sensor of my bicycle computer is torn off and lost. At my destination (Kendari / Indonesia), I can neither find a new sensor nor a new computer. I go without a computer for over a week which is a pity as my GPS gives me trouble at the same time, so that all my distance figures on southern Buton are rough estimates.

Well, eventually I find a way to make a new sensor for this computer:

Bicycle computer repair, step 1

Step 1 - Find parts

Step 2 - Attach new cable to holder

Push out the contacts from the holder, replace the old cable with a new one, push the contacts back in so they hold the copper braid of the new cable, secure the new cable with a cable tie.

Bicycle computer repair, step 3

Step 3 - Prepare enclosure for sensor

Open the plastic enclosure of the door alarm's magnet and remove the magnet.
Drill a hole from one end into the enclosure, feed cable through, make a strain relief with cable tie.
Remove the reed contact from the door alarm's main unit. I take it together with a piece of the circuit board, as to avoid any risk of cracking the glass from heating the solder joints with a lighter.

Bicycle computer repair, step 4

Step 4 - Solder wires to reed contact

TV repairmen have the necessary equipment. This nice guy helped me out.

Bicycle computer repair, step 5

Step 5 - Seal sensor enclosure

A few drops of hot wax hold and seal the reed contact. The lid is put on while the wax is still hot.

Works again, as good as new !

Bicycle computer repair, the outcome Bicycle computer repair, the outcome Bicycle computer repair, the outcome