Introduction of KeKePad


KeKePad is a new generation of platform for wearable and e-textile projects. It’s 100% compatible with Arduino LilyPad USB, you can programme it with Arduino IDE. It uses an ATmega32u4 chip and has built-in USB support function, so you can connect KeKePad to your computer directly by a Micro-USB cable and program it.

Traditional wearable and e-textile platforms use conductive thread for wiring. The conductive thread is expensive and has many drawbacks in electronics, it’s bare without any insulation, its resistance is very high.

KeKePad platform introduces a new way of wiring and connection. We get rid of conductive thread and use super tiny Ke connectors and ultra thin Ke cables for the whole platform. The cable wire diameter is only 0.32mm, and is flexible like thread, it’s ultra-thin, strong and smooth with Teflon insulation.

The KeKePad 1024

KeKePad controller board is small, it has a round shape (50mm in diameter), there are 12 tiny 3-Pin Ke Connectors and 11 sewtab pins, provides full interfaces for the applications. (Please refer to the Pin Mapping for details).

the kekepad 1024
Like the controller board, all the modules have standard 3-pin Ke connectors and sewtab pins for the wiring. So, KeKePad platform is compatible with conductive thread wires too.

Key Features

  • Fully Arduino Compatible;
  • USB Compatible: Easy to Program;
  • Two systems of interfaces: Ke Connectors and sewtab pins;
  • Compatible with the existing wearable modules using conductive thread;
  • Tiny and high quality;


  • Microcontroller: ATmega32u4
  • Operating Voltage: 3.3V
  • Input Voltage: 3.7V to 9V (Max. 6v is recommended)
  • Flash Memory: 32 KB (ATmega32u4) of which 4 KB used by bootloader
  • SRAM: 2.5 KB
  • EEPROM: 1 KB
  • Clock Speed: 8 MHz
  • Power Input: BAT_IN Port (3-Pin Ke Connector)
  • Power Output: Pin1(+) and Pin3(-) of Port 1, 2,4,5,6,10 is 3.3v and GND; The Port BAT_OUT has an unregulated output (VBAT) directly from the battery
  • Dimensions: 50mm in diameter (PCB thickness: 1.2mm, Max. height with components: 4.4mm)
  • Weight: 9g

 06 KeKePad introduction

Power and Indication

The power supply for KeKePad is either from MicroUSB or from the BAT_IN port.
Just connect the Coin Cell Battery Holder or a Li-polymer battery (you may need to use the Switch/Adapter) to KeKePad BAT_IN Port with Ke Cables to power it.
The regulator on KeKePad is MCI5219, it can work at Max. 12V input voltage, but we recommend the Max. voltage at 6V in normal usage.

The KeKePad has a slide switch on board, it can switch the board power supply on or off.

For safe usage, we do not include the charging circuit on KeKePad, but provide a battery charger module for Li-Po batteries.

There are 3 indicator LEDs on KeKePad: RX, TX LEDs (will flash when transmitting data )and User LED.

Interface and Pin Mapping

As shown below in the Table, the modules are connected to the KeKePad controller board by Ke Cables.

To simplify the connection, only 3-pin Ke connectors are introduced in the platform. Some modules only have 1 pin for signals, so one connector is enough (VCC S GND); Some modules use USART, I2C or SPI communication, so there are two 3-pin connectors on the modules, one is for power and another one is for signals, the ports with VCC and GND (P1, P2, P4, P5, P6, P10 and BAT_OUT ) can all be used as the power supply ports;

There are 12 functional pins (D7,D10,D6,D9,D12,D5,D11; A5,A8,A3,A4,A2) together with USART, I2C and SPI interface for all kinds of applications. Each of the pins can be used as input or output and have the same functions as on LilyPad Arduino USB.
Some of the Pins have specialized functions:

PWM: D6, D10, D5, D9, D11, these pins provide an 8-bit PWM output, please refer to Arduino analogWrite().

Analog Inputs: A5, A7, A3, A4, A2, A10(D10), A9(D9), A11(D12), A6(D4), these are analog input pins, please refer to Arduino analogRead() and analogReference().

UART: RX(D0), TX(D1). These pins are used for serial communication.

I2C(TWI): SCL(D3), SDA(D2), these are I2C communication pins, please refer to Arduino Wire library.

Please see the Pin Mapping below:

Pin Mapping KeKePad 01  1024

Pin Mapping  KeKePad 01 11

The Modules and Compatible Ports

This Table shows the compatible ports on KeKePad for the Modules.



Compatible Ports

Ke Light Sensor Analog light sensor TEMT6000 P2; P4; P5(A10); P6(A9);
Ke UV Sensor Analog UV sensor ML8511 P2; P4; P5(A10); P6(A9);
Ke Color Sensor I2C color sensor TCS34725 P8 + Port with VCC 3.3v (P1,2,4,5,6,10);
Ke Barometer I2C barometer BMP180 P8 + Port with VCC 3.3v (P1,2,4,5,6,10);
Ke Temp. and Humidity Sensor I2C temp. and humidity sensor Si7021 P8 + Port with VCC 3.3v (P1,2,4,5,6,10);
Ke Accelerometer Analog accelerometer ADXL335 P3 + Port with VCC 3.3v (P1,2,4,5,6,10)
Ke Vibration Sensor Digital vibration sensor P1
Ke Vibration Motor  PWM PWM(P5, P6, P10, BAT_OUT)
Ke Buzzer  PWM PWM(P5, P6, P10, BAT_OUT)
Ke Sound Detector LMV324 Analog sound sensor with 3 input P3 + Port with VCC 3.3v (P1,2,4,5,6,10)
Ke Sound Detector Analog sound sensor with 1 input P2; P4; P5(A10); P6(A9);
Ke MP3 V1.0  USART P7
Ke Pixel Mini Digital GRB LED with Integrated IC P1, P5, P6, P10 and BAT_OUT
Ke Pixel Ring Digital GRB LED with Integrated IC P1, P5, P6, P10 and BAT_OUT
Ke TH Pixel Mini Digital RGB LED with Integrated IC P1, P5, P6, P10 and BAT_OUT
Ke Smart LED Digital RGB LED with SMD IC P1, P5, P6, P10 and BAT_OUT
Ke Pixel Stick Digital GRB LED with Integrated IC P1, P5, P6, P10 and BAT_OUT
Ke Button Switch button P1,2,3,4,5,6,10 and BAT_OUT
OLED Display SPI 128*64 OLED screen P9 + Port with VCC 3.3v (P1,2,4,5,6,10)
Ke Li-Po Charger Power Supply BAT_IN
Ke Coin Cell Battery Holder Power Supply BAT_IN

Ke Connectors and Ke Cables

Ke Connector and Ke Cable is developed by KeKe Smart. Ke Cable is special, because no such thin cables was produced before, with several months’ hardworking, we produced it successfully, the cable wire diameter is only 0.32mm (OD),  so it’s the thinnest cable in the world (with crimp terminal), it’s so thin and flexible, we must use Laser Technology in production! The cable has many advantages in wearables and e-textiles.

compare of conductive thread and Ke cable wire 1024

The Compare of Ke Cable Wire and Stainless Steel Conductive Thread
03 3-pin Ke cable, needle and 3-pin JST cable

The Compare of Ke Cable and a Normal JST Cable

Ke Connector is so tiny, it’s only 1/5 the size of a normal 3-pin JST connector;  The connector has a hook, when the cable housing is inserted into the wafer, it will be hooked and can not be pulled out unless you press down the hook end.

2.2.03 02 Ke cable

Tips: Sometimes, the connection is tight, don’t pull the cable to release it! You may break the cable! The right way is pressing down the housing hook-end and push the head of it with your nail.

compare 1024


Because KeKePad is 100% compatible with LilyPad Arduino USB, to program it, you can just use Arduino IDE, please download the Windows or Mac OS X version IDE .

KeKePad is already pre-burned with a Arduino LilyPad USB bootloader, so you can just upload new sketches into it, no need to use an external hardware programmer.

Just plug into a MicroUSB cable and connect KeKePad with your computer, following the instructions, you can upload sketches to KeKePad and start to use it, for details, please read our Getting Started pages for detail.

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