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4-Key and Wheel Capacitive Touch Sensing Shield BMK56T004A
US$3.90(Excl. Tax)
In stock
Quantity
195
pieces
Product ID
BMK56T004A
The BMK56T004A is a capacitive touch expansion board featuring 4 touch keys and 1 touch wheel, powered by the BS83B16C touch MCU. When a finger touches the wheel or any of the 4 keys, the corresponding LED lights up instantly. This board offers excellent stability and anti-interference performance, making it ideal for interactive applications such as smart home control panels.
BMK56T004A is a module designed by Best Modules specifically for the micro:bit and Arduino (BMduino) ecosystems. Depending on the user’s development environment and the main board being used, it can be paired with the
micro:bit IoT Expansion Board BMB81TM01A
or the
BMduino IoT Expansion Board BMB81TB01A
to make sensor and module wiring more intuitive and integration significantly faster, greatly improving development efficiency.
Supported I2C commands include:
- Reading touch status for both the wheel and keys (wheel outputs positions 1~8; keys output as bit values)
- Setting/reading the touch threshold for each channel (lower values increase sensitivity)
- Reading the firmware version
For power management, the board defaults to standby detection mode on power-up. It switches to active mode upon detecting touch, and if no touch is detected for about 8 seconds, it automatically returns to standby mode—balancing quick response with low power consumption.
Features
Operating Voltage: 2.5V ~ 5.5V
Operating Current: 4mA @ 5V
Standby Current: < 30μA @ 5V
Automatically enters standby mode after about 8 seconds of inactivity
Excellent stability and strong noise immunity
Touch and Indicators
- 1 × Touch Wheel (positions 1~8 mapped to LED1~LED8)
- 4 × Touch Keys (KEY1~KEY4 mapped to LED9~LED12)
- Adjustable sensitivity with 55 levels (range: 10~64), configurable individually for each position/key
Communication Interface
- I2C address: 0x74; speed ≤ 400kHz
- Connection: Directly plugs into BMduino or via BMCOM
This board can be used directly with an Arduino UNO or our BMduino-UNO development board. Simply align the pin header on the back of the BMK56T004A with the Arduino UNO or BM53A367A sockets—no additional wiring needed.
Pin Name
BM53A367A Pin
Function
INT
D2
Output pin No touch: High level Touch detected: Low level
SCL
D19/SCL
I2C clock line
SDA
D18/A4
I2C data line
IOREF
IOREF
Power input (use 3.3V with BM53A367A)
RESET
RESET
Reset BM53A367A
GND
GND
Ground
Alternatively, you can connect the BMK56T004A to the BM53A367A via the BMCOM interface.
Pin
Pin Name
Function
1
GND
Ground
2
VDD
Power supply: 2.5V ~ 5.5V
3
SDA
I2C data line
4
SCL
I2C clock line
5
INT
Output pin No touch: High level Touch detected: Low level
Technical Q&A
Q1: How does it enter sleep mode?
A: The board automatically enters sleep mode after about 8 seconds of no activity.
Q2: How can it be woken from sleep?
A: It wakes automatically when a touch is detected.
Q3: Can it detect touches through glass or acrylic?
A: Yes, as long as the cover material is no thicker than 3mm, and sensitivity is adjusted accordingly for optimal touch response.
Resources
MCU: Holtek BS83B16C, enhanced touch-type Flash MCU, with datasheet, package dimensions, and related resources.
