No OS. There's just a setup() function and a main loop() that runs forever. It's really really fun, at least to my brain. If you want to see how it works with

No OS. There's just a setup() function and a main loop() that runs forever. It's really really fun, at least to my brain. If you want to see how it works without spending any money, TinkerCAD (https://tinkercad.com https://tinkercad.com) will let you layout, program, and simulate an Arduino. They're somewhat less powerful than the ESP32 CAM proposed to replace this, but it's a good way to "dip your feet" in programming and wiring up microcontrollers.