Arduino Shields

A shield plugs onto a board's headers and adds hardware the board does not have. Juno drives each one from plain Java: most need no Arduino library, and every shield class hands its pins and devices to the program, so a unit test can pass mocks instead. Seat a shield directly on the board, and check the pins before stacking two.

Shield	Adds	UNO R3	UNO WiFi Rev2	UNO R4 WiFi	UNO Q	Nano ESP32
TFT Touch Shield	2.8" color touch display, microSD		✓	✓	✓
Grove Base Shield	Grove sockets	✓	✓	✓	✓
Arduino 9 Axis Motion Shield	BNO055 orientation sensor	✓	✓	✓	✓
LCD Keypad Shield	16 × 2 character LCD, five buttons	✓	✓	✓	✓
AZDelivery Data Logger Shield	microSD, real-time clock	✓	✓	✓	✓
Arduino WiFi Shield	Wi-Fi for a board without a radio	✓
Nano Connector Carrier	microSD, Grove and Qwiic sockets					✓

TFT Touch Shield

The ELEGOO 2.8" shield: a 240 × 320 ILI9341 color display on an 8-bit parallel bus, a resistive touch panel and a microSD socket. TftTouchShield draws, prints text and reads touches, and ParallelBus streams pixels from the runtime. Juno's games run on it.

Grove Base Shield

Seeed Studio's passive adapter: every Grove socket is an ordinary UNO pin, and GroveBaseShield names them. Plug a Grove module in and pass the socket's getter to its driver. See Grove for the sensors.

Arduino 9 Axis Motion Shield

A Bosch BNO055 that fuses its accelerometer and gyroscope and reports the heading in degrees. NineAxisMotionShield reads it over I2C with no Arduino library, which suits measuring how far a vehicle has turned. It holds D7 as the sensor's reset line.

LCD Keypad Shield

A 16 × 2 character LCD on D4-D9, its backlight on D10, and five buttons read through one analog pin. LcdKeypadShield needs no library.

AZDelivery Data Logger Shield

A microSD socket on the UNO's SPI pins with chip select D10, plus a DS1307 real-time clock that Juno does not drive. DataLoggerShield.getSdCard() gives the card, which programs use for files and for Wi-Fi credentials kept out of the source. Its D10 is also the LCD Keypad Shield's backlight.

Arduino WiFi Shield

The retired Arduino WiFi Shield gives the UNO R3, which has no radio, Wi-Fi, UDP, TCP and plain HTTP through new ArduinoWifiShield().getWifi(). It reserves D4, D7 and D10, so it cannot be stacked with the LCD Keypad Shield.

Nano Connector Carrier

Arduino's passive carrier for the Nano ESP32: a microSD slot, four Grove sockets and a Qwiic connector, all named by NanoConnectorCarrier. See the Nano ESP32 page for its pin map and examples, including remote-controlling a LEGO RCX over infrared.