Smarter Sprinkler is a combination of open source hardware and software developed during the Berkeley Cleanweb Hackathon. The system uses sMAP (simple measurement and actuation profile) -- software developed at UC Berkeley -- to aggregate data streams from multiple publicly available APIs in order to determine optimal watering schedules and duration. The system represents significant gains over 'smart' sprinkler systems currently on the market, which typically only take 24 hour rainfall totals into account. The cloud-based control scheme allows one Internet based server to control an unlimited number of clients, making this solution ideally suited to city-wide water demand response programs focused on water conservation. This talk will discuss the system's hardware and software, and detail several simulated deployment scenarios.