An autonomous wireless transmitter with a piezoelectric energy harvester is presented for home automation and Internet of Things applications. The proposed ultra-low-power transmitter and high-efficiency energy harvester facilitates battery-less remote control with a small feature size. Each shot of the PZT generator produces an energy of more than 20 μJ Moreover, the piezoelectric harvester achieves a high conversion efficiency of up to 80% through the use of an inductor-switching circuit. Finally, the wireless transmitter realizes ultra-low power frequency synthesis by means of injection locking and frequency multiplication techniques. Operating at the 433 MHz ISM band, the transmitter delivers an output power of -12.9 dBm with a power consumption of 750 μW. A prototype device is fabricated with a size of 8.5 × 3.5 × 2.5 cm3.