LKP

レンくんピアノ (Len-kun Piano)

Capacitive touch slider controller for rhythm games.

Contents

pcb/LKP-Core

Microcontroller board for use with LKP electrode boards. Supports up to 32 channel of self capacitance input. Includes a WS281x LED driver channel with protection resistor. Supports I2C or UART as communication methods.

For sample firmware for use with LKP-Core, see LKP-FW.

Requires KiCad version 5.99 (nightly) (supports kicad_pcb format >= 20210816).

Pin mapping

I/O port:

#	Description
1	GND
2	INT
3	SCL/RX
4	SDA/TX
5	GND
6	+5V

WS281x LED connector:

#	Description
1	GND
2	LED

SWD connector:

#	Description
1	VTARG
2	GND
3	RESET
4	SWCLK
5	SWDIO

pcb/LKP-Diva-Electrode-Tile

Electrode board for Project DIVA Future Tone slider controller. Works as a 2-tile setup. Both tiles use the same design, with right tile being a 180 degree rotated version of the left tile.

Requires KiCad version 5.99 (nightly) (supports kicad_pcb format >= 20210228) for hatched fills.

BOM

LKP-Core

• C1, C4, C6, C10: Generic 1uF 0603 X5R ceramic capacitor. (I used CC0603KRX5R8BB105)
• C2, C3, C5, C8, C11: Generic 100nF 0603 ceramic capacitor. (I used CL10B104KA8NNNC)
• C7: GRM2195C1H103JA01D.
• C9: GRM21B5C2J222FWAAL.
• C12: Generic 10uF EIA-3216-18 tantalum capacitor.
• D1: Generic SOD-123 Schottky diode (MBR0520L).
• D2: Generic 0805 LED (yellow color).
• FB1: Generic 1206 ferrite bead (330ohm@100MHz).
• J1, J2: Straight female .1" header 2x9.
• J3: JST XH 2 positions.
• J4: Straight male .1" header 1x6.
• J5: Straight male .1" header 1x5.
• J6: Angled male .1" header 1x2 or JST XH 2 positions
• R1: Generic 1kohm 5% 0603 resistor.
• R2: Generic 470ohm 5% 0603 resistor.
• R3, R4: Generic 560ohm 5% 0603 resistor.
• RN*: Generic 560ohm 5% 0402x4 convex resistor array (I used 4D02WGJ0561TCE).
• U1: CY8C4246AZI-M445 (or CY8C4247AZI-M485, Needs minor firmware modifications).

LKP-Diva-Electrode-Tile

• J1: Straight male .1" SMD header 2x9 (without bumps at the bottom).
  • This can be hard to find. For small scale DIY manufacturing try searching "pin header double smd" on aliexpress.

Powering

By default LKP expects 5V power. Using lower supply voltage down to 1.8V is possible by modifying the power specs in LKP-FW and adding a level shifter module to the WS281x driver pin (labeled as LED on board). Reference voltage for I/O can be approximated by tapping into the VTARG pin on the SWD port.

Known issues / Erratas

• (LKP-Core v1.0) The reverse voltage protection diode (D1) does not protect C12. Proceed with caution when connecting the power to make sure the polarity is correct.
• (LKP-Core v1.1) When used with LKP-Assy, connector J4, J5 and J6 may collide with the bottom of LKP-Assy. A workaround would be soldering all the specified connectors on the back side of the PCB instead. Also, when using LKP-IF-Qwiic, J4 and J5 must be soldered on the back side.
• (LKP-Core v1.2b) Changes of some parts that I have and I want to use: J1, J2 to JST XH, J4 from 4 to 6 pin, C9 to 0805 size, FB1 to 1206 size and changes in silkscreen.