Arduino connected to T3035H 30A triac thru a zero-crossing MOC3063 optoisolator.

Modes: single pulse, dual pulse.
Set pulse time in 1/2 cycles (8.3 ms at 60Hz).

Inputs are a mode switch, an up/down time switch.
Outputs are two mode diodes, a pulse diode, and a 4x 7-segment LED.

Parts
T3035H
MOC3063

Triac projects
Triac_v1.0.pdf, project link, Tindie.
Zero_Cross_v1.0.pdf, project link, Tindie.