USB FIRMWARE INSTALLER

Install SCUBA Regulator Tester firmware.

Install SCUBA Regulator Tester firmware using desktop Chrome or Edge, a USB data cable, and your LilyGO T-Display-S3. Keep the board outside the case, leave the optional battery unplugged, and close serial monitors before connecting. You can check the display, buttons and hotspot before purchasing a licence.

1. Check your board

CPT uses the standard LilyGO T-Display-S3 with 16 MB flash and its built-in display. The installer checks chip family and flash capacity before writing. Confirm the board is for this SCUBA Regulator Tester: another product may use the same hardware.

I am installing CPT on the correct board. This replaces its current application.

Check wiring and supported parts →

2. Register this installation

Your FiddlerCrab account

Use the same verified email as your other FiddlerCrab devices. This website has its own sign-in session.

Account email I request device/licence registration and accept the registration terms.

Registration links your verified email to the board, licence and completed flashes. These details also go to the private licence-administration inbox. A failed write is not counted as a successful installation. This does not subscribe you to marketing. Privacy details.

Checking your account…

3. New board or existing tester?

Choose explicitly; neither mode is selected for you. Full install is for a new board and can erase stored data. Update only is for an existing CPT installation with the standard partition layout. Export records before recovery.

Choose an installation mode to check the production release.

Choose Full install for a new board, or Update only for an existing tester.

Installation stops before erase/write if the board, registration or release checks fail.

Optional product emails

SCUBA Regulator Tester emails

These choices are separate from sign-in, licence registration and analytics. Both are off by default; installation works without either.

Email for optional updatesEmail me firmware updates and important notices for this product.Email me occasional product news and offers for this product.

Only after a successful installation will we send a confirmation link for your selected topics. Nothing is subscribed until you confirm. Every product email has an unsubscribe link. Your licence is unaffected. Privacy and retention.

Email signup is off.

4. Connect and activate

After installation, confirm the board starts, then complete final assembly with power disconnected. Power the finished tester and join the hotspot shown on its display; the default key is scuba-test.
Open http://192.168.4.1, then About. Copy the 12-character Device ID.
Save that Device ID, then switch back to internet Wi-Fi (or use another internet-connected device). Check availability and buy the €25 one-time licence for that board. All measurement functions are included. Hardware is separate; no subscription.
After confirmed payment, copy the full key. Rejoin the tester hotspot and reopen http://192.168.4.1, then paste the matching key into About → Activate device. Both key activation and measurement work without internet.

Check licence availability · €25

Checkout uses FiddlerCrab’s existing payment service. Your CPT licence and order are separate from Nitrox and Trimix licences. Wi-Fi setup, Device ID and activation are accessible before purchase.

Next: zero and take your first reading →

If USB connection fails

Try a known data cable and another USB port. Close Arduino, PlatformIO and other serial tools. For manual bootloader entry, hold the onboard BOOT button, tap RESET, then release BOOT and reconnect in the installer. The external MENU button on GPIO1 is not BOOT.

Do not select a different product to work around a board-check error. Use the exact board in the build guide.