Following a design made days ago this is meant to apply constant pressure on the chain without creating unnecessary resistance. The length of the bolt determines the maximum height of the skate wheel but its final height is adjustable by the nuts surrounding it.
Sketch of design
A ceramic magnet base was purchased. This is simply a steel cup surrounding a magnetic donut. The cup usually has a hole in the center. The hole in this magnet was drilled from 3/16” to 5/16” ø.
The hole is 5/16", not the diameter of the magnet
The only height adjustment necessary was to put two flat washers between the bolt head and the skate wheel bearings. The nut which would have held to the bottom of the magnet base was eliminated to allow the wheel and bolt to move so a rubber band could apply tension as opposed to a hard position set by place the magnet and wheel near the chain.
Rubber band to apply tension
Movement of chain tensioner
Physically install Arduino and shield
Test + Debug