Offered by Autodesk, Tinkercad is a free online platform you can use to build and test out your Arduino circuits ... ultrasonic sensor, keypad), output (e.g., LED, DC motor, LCD), power (e.g ...

If you want to add a keypad to your Arduino project, the options are pretty limited. There’s that red and blue 4×4 membrane we’ve all seen in password-protected door lock projects ...