This lecture covers the fabrication and working principles of printed sensors for humidity and temperature measurements. Topics include inkjet-printed capacitors, resistors, and chemoresistive gas sensors. The sensors' materials, fabrication techniques, and response to environmental changes are discussed, emphasizing the advantages of printed sensors in terms of cost, flexibility, and integration with electronics. Additionally, the lecture explores the use of organic electrochemical transistors as sensors for various ions, chemicals, and biological substances, highlighting their potential applications in bioelectronics.