"ARM CPUs are not unique in energy harvesting technique implementations.<br><br>This firm <a href=""http://onio.zero/"">ONiO.zero</a> announced a RISC-V implementations using similar techniques intended for microcontrollers some years ago which ran at 24MHz while requiring no outside electrical input.<br><br>Meanwhile", Micro Magic demonstrated a 5GHz RISC-V implementation late in 2020 which utilized just 1W.<br><br>In other words, while ARM is efficient, it's also from the 1980s, and RISC-V (from 2010) is already looking much better.