# SparkFun RedBoard Projects

Arduino sketches for SparkFun RedBoard, built and uploaded via `arduino-build.sh`.

## Prerequisites

- [arduino-cli](https://arduino.github.io/arduino-cli/)
- Run `./arduino-build.sh --setup` once after installing

## Quick Start

```bash
./arduino-build.sh --devices           # find your board
./arduino-build.sh --monitor ./blink   # build, upload, serial console
```

## Project Layout

```
sparkfun/
    arduino-build.sh        Build/upload/monitor tool (run --help)
    blink/
        blink.ino           LED blink + serial hello world
```

## Two-Terminal Workflow

```bash
# Terminal 1: persistent serial monitor
./arduino-build.sh --watch

# Terminal 2: edit, build, upload (monitor reconnects automatically)
./arduino-build.sh ./blink
```

## Adding a New Sketch

```bash
mkdir my_sketch
# Create my_sketch/my_sketch.ino (filename must match directory)
./arduino-build.sh --verify ./my_sketch   # compile check
./arduino-build.sh ./my_sketch            # build + upload
```

## Troubleshooting

### Ubuntu: Board not detected (CH340 / RedBoard)

On Ubuntu, `brltty` (a braille display daemon) may claim the CH340 USB-serial
interface before the `ch341` kernel driver can bind to it. The board will appear
in `lsusb` but no `/dev/ttyUSB*` device is created.

Symptoms in `dmesg`:

```
usb 1-3.1.3: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
```

If you are not using a braille display, remove `brltty` entirely:

```bash
sudo systemctl stop brltty-udev
sudo systemctl disable brltty-udev
sudo systemctl stop brltty
sudo systemctl disable brltty
sudo apt remove brltty
```

Alternatively, to keep `brltty` installed but block it from claiming CH340
devices, add a udev rule:

```bash
sudo tee /etc/udev/rules.d/99-ch340-no-brltty.rules << 'EOF'
SUBSYSTEM=="usb", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", ENV{BRLTTY_BRAILLE_DRIVER}="none"
EOF
sudo udevadm control --reload-rules
sudo udevadm trigger
```