Traffic Light Trigger for your Bike

Step 2 Epoxy the magnet, backed with a washer, to the shoe

I used PC-7 heavy-duty epoxy paste and coated the entire magnet, both to protect it and to stick it firmly to the heel. Backing the magnet with a washer helps to focus the magnet field, aiming it down (and not up into your heel, not that it should do anything to you anyhow).