It's kind of follow-up of my previous project for a sound board. With this project I obtain the same results, but using a prototype shield and no sparse components. In addition, all pins of the Arduino are now reachable for any kind of sensor, besides the shown electret. The price is that of the ProtoShield (5$), of the ESP01 (3$), and of the Capacitor().The schema and test programs are at https://bitbucket.org/augusto_ciuffoletti/esp01_protoboard/. The library can be downloaded from https://bitbucket.org/augusto_ciuffoletti/atlib. The shield works "as is" only with an original Arduino Uno board or with clones with the 3.3 output equivalent to that of the original board. Successfully tested with Elegoo.