Arcane tripwire

As an action you can activate the arcane tripwire and attach it to a plane surface. When a creature walks within 10 feet of the tripwire and cross the tripwire’s light-wire coming in a straight line from the surface, it activates. Any creatures within 10ft have to make a DC 15 DEX saving throw, if the creature fails, the explosion deals 1d6 force damage, knocking the affected creature prone. On a success the creature takes half damage and is not knocked prone If the creature is within 15 it has to make the same saving throw or take 1d4 force damage, half on a success.