[Bill Porter] has a tip for designing circuits that have multiple connections to a single microcontroller UART. This stemmed from a review of a friend’s circuit design that used the UART in t… ...

so tinkercad has circuit designand arduno now, a real arduino is $20, IDE is free, fritzing is free and does all the exact same layout stuff locally, you save your files and keep them forever.

Build Your Own Arduino Voltmeter Circuit and Voltage Divider Which Can Measure Voltages From 0V to 30V, Including 12V. ... Where electronics engineers discover the latest toolsThe design site for ...