Recently, I built a temperature and humidity display that uses a thermochromic material heated and cooled by peltier elements. <br><a target="_blank" rel="noopener noreferrer" href="https://hackaday.io/project/167180-thermochromic-temperature-humidity-display">https://hackaday.io/project/167180-thermochromic-temperature-humidity-display</a><br>In this project I recreated a smaller and much simpler version using a PCB heater.