Below is a complete, step-by-step checklist for getting the Arduino IDE to see and upload to a HexBright (the original or Flex version).

Everything is written for the current Arduino IDE 2.x (the same steps work in 1.8.x).

1. Plug the HexBright in (USB)

OS What you should see
Windows Device Manager → Ports (COM & LPT) → Arduino HexBright (COMxx)
macOS System Information → USB → HexBright (or Arduino)
Linux ls /dev/ttyACM* or ls /dev/ttyUSB* → /dev/ttyACM0 (or similar)

If nothing appears → install the CDC driver (see §2).

2. Install the CDC-ACM driver (only needed once)

OS How
Windows 1. Open Device Manager → right-click the unknown device → Update driver → Browse my computer → point to the Arduino IDE folder drivers\\ftdi (or just install the Arduino IDE – it bundles the driver). <br>2. If it still shows “Unknown”, use Zadig → select the HexBright → install libusbK.
macOS No driver needed (built-in).
Linux Add your user to the dialout group: sudo usermod -a -G dialout $USER and reboot.

3. Add the HexBright board definition to the IDE

  1. Create the folder

    ~/Documents/Arduino/hardware/hexbright/          (macOS/Linux)
C:\\Users\\<you>\\Documents\\Arduino\\hardware\\hexbright\\   (Windows)

  2. Create boards.txt inside that folder with exactly this content:

    #####################################################
hexbright.name=HexBright

hexbright.upload.protocol=arduino
hexbright.upload.maximum_size=30720
hexbright.upload.speed=57600
hexbright.upload.tool=avrdude

hexbright.bootloader.low_fuses=0xff
hexbright.bootloader.high_fuses=0xde
hexbright.bootloader.extended_fuses=0x05
hexbright.bootloader.path=optiboot
hexbright.bootloader.file=optiboot_atmega328.hex
hexbright.bootloader.unlock_bits=0x3F
hexbright.bootloader.lock_bits=0x0F

hexbright.build.mcu=atmega328p
hexbright.build.f_cpu=16000000L
hexbright.build.core=arduino
hexbright.build.variant=standard

  3. Restart the Arduino IDE.

  4. Select the board:

    Tools → Board → HexBright

  5. Select the port:

    Tools → Port → COMxx (HexBright) (or /dev/cu.usbmodem… on macOS)

4. Verify with a minimal sketch

// File → Examples → 01.Basics → Blink  (modify pin)
void setup() {
  pinMode(9, OUTPUT);          // Main LED is on pin 9
}

void loop() {
  digitalWrite(9, HIGH);
  delay(500);
  digitalWrite(9, LOW);
  delay(500);
}

Click Upload.