Puchi-BLE - Wireless Microcontroller

Features

• nRF52840 wireless module
• Li-Po battery charger (4.2V Lithium @ 100mAh)
• USB Type-C (data and charing)
• Pro-Micro drop-in replacement (same size, pinout)
• Support for QMK (nrf52 fork) and ZMK (recommended)
• USB Mass Storage for firmware update
• True wireless split keyboard (no TRRS cable, or separate receiver)
• Also wired split keyboard with USB-C and Serial/I2C connection
• Comes with Adafruit nRF52 Bootloader (UF2 Mass Storage updates and DFU serial)
• System requirements: Bluetooth 5.0

Battery (read carefully)

• Puchi-BLE supports 1S LiPo batteries (4.2V)
• Only use LiPo batteries with a protection circuit, because the Puchi-BLE has no low voltes (discharge) protection for batteries
• A 301230 (3.0 x 12 x 30 mm) LiPo batterie fit between 4.5mm tall pin sockets
• Connect the batterie to B+ and B-, or RAW and GND (this pears of pins are internally connected)
• Avoid reverse polarity (nRF52840 chip is usually destroyed first)
• Note that a few keyboards have RAW and VCC pins connected together (namely Helix and Gherkin), and will kill the controller (RAW pin is for the charger only). You may just not solder RAW pin to the keyboard as a workaround.

FAQ

• Do i need a TRRS cable to connect the split keyboard halfs?

  No, the slave side connects wireless to the master side. Optional you can use a cable (no charge over TRRS cable).

• What's the battery life?

  Approximately 2weeks with a 100mAh battery (no oled, or led‘s).

• Is there a lag while typing?

  Bluetooth devices can reach a latency of 1.3 ms. Lower latency means more power drain and reduce the battery life.

• Is it possible to switch between Bluetooth devices?

  Yes, QMK and ZMK have support for up to 5 Bluetooth profiles.

• What batteries work with the Puchi-BLE?

  LiPo batteries with 1S. Also important is that the LiPo batterie has a protection circuit

• Are batteries available in the shop?

  No, due to the german law, i don’t offer batteries in the shop. You can get LiPo batteries on Ebay and Aliexpress.

• What are the EXT_VCC and EXT_GND? Are they the same pins as VCC and GND?

  Yes. Power output is sofware-controlled to save battery (RGB LEDs draw up to 1 mA each when off).

The Puchi-BLE is heavily based on the open source project nRFMicro from Joric.
For each Puchi-BLE sold, a small amount is donated to the creator.

The nRFMicro 1.3+ ZMK configuration (more info's) is compatible with the Puchi-BLE REV1. Same for the QMK nrf52 fork (more info's).

Pinout

Service Pins

• P0.18 - RESET
• P1.10 - BLUE_LED (P0.15 on nice!nano)
• P1.09 - POWER_PIN (EXT_VCC control, P0.13 on nice!nano) (1-off, 0-on)
• P0.04 - BATTERY_PIN (analog battery voltage in mV, 820kΩ/2MΩ)

Low drive (low frequency) pins

• P0.31, P0.29, P0.02, P1.15, P1.13, P1.10, P0.30, P0.28, P0.03, P1.14, P1.12, P1.11, P0.10, P0.09, P1.07, P1.06, P1.05, P1.04, P1.03, P1.02, P1.01

Normal (high frequency) pins

• P0.00, P0.01, P0.26, P0.27, P0.04, P0.05, P0.06, P0.07, P0.08, P1.08, P1.09, P0.11, P0.12, P0.14, P0.16, P0.18, P0.19, P0.21, P0.23, P0.25, P0.13, P0.15, P0.17, P0.20, P0.22, P0.24, P1.00

Detailed pin information can be found on the Nordic Infocenter.

Controller comparison

Schematic