Review on Pro Engineered PWM AC Voltage Dimmer 50/60Hz 80-240VAC for Arduino Raspberry - Leading Edge Dimmer for AC Motor, Pump, Fan, Light, Heater - Maximum 500W - Onboard Snubber Circuit - Worldwide Compatibility by Adam Matthews

Easy to use, careful PCB design safe yet reliable. Gently reduces the stress on the bulb with an asynchronous PWM signal (no need for zero crossing detection and direct triac control). I am using this module to power a 30 watt load of small light bulbs in a rain gauge. The heat from the bulbs is used to melt the snow, whereas a rain gauge would only be covered with snow. This little module works great controlled by the Raspberry Pi's PWM output. The PCB design is solid and clean. The high voltage connectors are on the opposite side of the PCB from the low voltage connectors, making it easier to create a safer design. It is an excellent product for safe variable control of AC loads. For your health!