What you see
A practical setup path for an individual Chromebook, before bringing a physical board to class.
Likely causes
- Local editing and compilation require JavaScript, WebAssembly, browser storage and a first compiler download.
- Physical USB work additionally needs Web Serial, a recognized device and permission under school policy.
Diagnostic steps
Check the browser before the board
Open Circuitera over HTTPS. Start a local Blink sketch and select Uno R3. Verify downloads the AVR toolchain and compiles in a worker on your device. If the school blocks downloads or storage, ask IT; signing in does not remove those restrictions.
Try a simulator-only lesson
Launch Blink in Simulator, press Run, and change one delay. The current simulator models supported Uno / ATmega328P circuits. No USB board, driver, or serial permission is needed for this lesson. Mega compilation does not enable Mega simulation.
Connect physical hardware deliberately
Use a USB data cable and a board profile that matches the processor and bootloader. Press Connect board to choose a port, then Upload after Verify succeeds. Managed serial-device policies or host drivers can prevent the port from appearing.
Finish with serial feedback
Use the Serial Hello World project and match Serial Monitor to Serial.begin(9600). A working compiler does not prove that a USB cable, port or bootloader is working. Diagnose those separately.
Prepare offline work and backups
While online, use Prepare offline compiler and wait for completion. Test the prepared workflow before disconnecting. Export a sketch or project ZIP before clearing site data or moving computers; browser storage can be evicted.
Board-specific notes
Uno/Nano use their USB-to-serial bridge. Mega’s extra UARTs are not separate browser ports. Leonardo/Micro native USB may re-enumerate during reset. Pro Mini requires an external adapter with the correct logic voltage.
Safe recovery
If a managed Chromebook blocks the port, keep the local sketch and use the supported simulator lesson. Ask the administrator to check device recognition and serial policy; Circuitera does not bypass it.
Evidence and references
Reviewed 2026-10-23 against Circuitera’s actual behavior. An editorial review is separate from a physical board test.
Circuitera implementation evidence
src/accounts/firebaseClient.js; src/App.jsx; src/PwaPanel.jsx