The ornamental design for an electronic dartmachine, as shown and described.
1. Electronic dart machine
1.1 : Perspective
1.2 : Front
1.3: Back
1.4 : Left
1.5 : Right
1.6: Top
1.7: Bottom
Each of the segment score numbers is indicated by LED display around target area; the electronic dart machine includes a display panel in upper part and a touch screen in lower part.