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Hardware Details

An ATtiny404 microcontroller sits between your controller and the parts on the board. It answers on I2C, reads the three pushbuttons, drives the three WS2812B-2020 RGB LEDs on one data line and plays the passive buzzer through a transistor. The board has no voltage regulator: everything runs from the 3.3 V that arrives on the Qwiic connector.

Top view of the Button, LED & Buzzer Board with Qwiic with callouts for the I2C address switch, the ATtiny404, the buzzer, both Qwiic connectors, the UPDI programming pins, the three pushbuttons and the three LEDs
Top down with marked features

Key specifications​

SpecificationValue
Interface
InterfaceI2C
Qwiic compatibleYes
Default I2C address0x30
I2C address changeableYes, 0x30 to 0x37 with a 3-position switch
I2C pull-ups10 kΩ to 3.3 V on SDA and SCL
Breadboard compatibleYes
Power
Supply voltage3.3 V, through the Qwiic connector
Other
MicrocontrollerATtiny404
LEDs3 × WS2812B-2020 RGB, 8 bits per colour channel
Buttons3 pushbuttons, each with a 10 kΩ pull-up and a 100 nF debounce capacitor
BuzzerPassive magnetic buzzer (MLT-7525), transistor driven, frequency set in Hz
Connectors2 × Qwiic, 2-pin SDA/SCL header, UPDI header for the ATtiny404 firmware
Dimensions38 × 22 mm
Mounting holes2 × 3.2 mm
Header holes1 mm

Pinout​

Pinout drawing of the Button, LED & Buzzer Board with Qwiic: Qwiic connectors on both sides, VCC, UPDI and GND on the left header, SCL and SDA on the right header, the buzzer at the top and user pushbuttons 1 to 3 along the bottom
Pinout of the Button, LED & Buzzer Board with Qwiic
ConnectorPinsDescription
Qwiic (×2)3V3, GND, SDA, SCLPower and I2C. The two connectors are wired in parallel: use either one, and the other passes the bus on to the next board.
2-pin headerSDA, SCLThe same I2C lines on header pins, for a breadboard. It has no power or ground pin.
UPDI headerVCC, UPDI, GNDProgramming interface of the ATtiny404, for its firmware. You do not need it to use the board.

Voltage and logic levels​

ConnectionSupported voltageNotes
Qwiic 3V33.3 VThe board's only supply. There is no regulator on the board.
SDA, SCL3.3 V high levelEach line has a 10 kΩ pull-up to the board's 3.3 V supply, which also powers the ATtiny404.

SDA and SCL go straight to the ATtiny404, whose pins must stay below its supply voltage plus 0.5 V: about 3.8 V on this 3.3 V board. Do not connect the board to a 5 V I2C controller without a level shifter.

The 2-pin header carries only SDA and SCL. When you use it, the board still needs its 3.3 V supply through a Qwiic connector.

Dimensions​

The Button, LED & Buzzer Board with Qwiic at an angle with its dimensions marked: 38 mm long, 22 mm wide, 3.2 mm mounting holes and 1 mm header holes
Isometry with dimensions

The board measures 38 × 22 mm. It has two 3.2 mm mounting holes, and the header holes are 1 mm.

Jumpers​

Top view of the Button, LED & Buzzer Board with Qwiic: a Qwiic connector on the left and right edges, the address switch and the buzzer along the top and three pushbuttons along the bottom edge
Top down

The board has no solder jumpers. Its only setting is the 3-position address switch.

JumperDefaultFunction
Address switch, positions 1 to 3All OFF: 0x30Sets the I2C address from 0x30 to 0x37, so up to eight boards can share one bus. A switch set to ON adds its bit to 0x30: position 1 adds 0x01, position 2 adds 0x02, position 3 adds 0x04.
123I2C address
OFFOFFOFF0x30
ONOFFOFF0x31
OFFONOFF0x32
ONONOFF0x33
OFFOFFON0x34
ONOFFON0x35
OFFONON0x36
ONONON0x37

When you change the address, pass the new address to the constructor in your sketch, for example ButtonLedBuzzerBoard_Soldered board(0x31); with only switch 1 ON. The library uses 0x30 when you give it none.