pierce 2.0

pierce 2.0 is a split modular wireless / semi-wireless 36 key column staggered keyboard. The design is inspired by Corne with more pinky stagger as well as only using 1u keycaps. It is possible to build a wireless version or a semi wireless version. If building the wireless version an additional reciever dongle is required. In the semi wireless version the wired half is also acting as a reciever for the wireless half. Both versions have full QMK support.
Supported switches: MX, Choc V1, Alps

The semi wireless version has a built in reset circuit for connecting a PS/2 pointing device.

There are 3 different PCBs: wireless (reversible), wired (right) and reciever.

A programmer is necessary to flash the wireless modules. A cheap option is getting an ST-Link V2 clone from ebay.

Bill of materials

Wireless

| Qty | Item | Comments | |----:|-----------------------------------------------|-----------------------------------------------------| | 2 | Pierce 2.0 wireless PCB | | | 1 | Pierce 2.0 reciever PCB | | | 1 | Pro micro or equivalent | | | 2 | Keystone 3034 Coin cell battery retainer | SMD | | 2 | 2032 3.3V Coin cell battery | | | 3 | YJ-14015 / Core51822 (B) | | | 3 | 1x4 pin Right-angle 2.54 mm header | For programming RF modulules. Optional, temporary soldered wires works fine| | 2 | 4.7 kΩ resistor | SMD 1206 | | 1 | 1117 3.3 V regulator | SMD SOT-223 | | 1 | THT momentary switch | 2 pin THT 6 mm |

Semi wireless

| Qty | Item | Comments | |----:|-----------------------------------------------|-----------------------------------------------------| | 1 | Pierce 2.0 wireless PCB | | | 1 | Pierce 2.0 wired PCB | | | 1 | Pro micro or equivalent | Elite C recommended if using trackpoint. (Pin D5 broken out)| | 1 | Keystone 3034 Coin cell battery retainer | SMD | | 1 | 2032 3.3V Coin cell battery | | | 2 | YJ-14015 / Core51822 (B) | | | 2 | 1x4 pin Right-angle 2.54 mm header | For programming RF modulules. Optional, temporary soldered wires works fine| | 2/4 | 4.7 kΩ resistor | SMD 1206, 4 if using trackpoint, otherwise 2 | | 1 | 1117 3.3 V regulator | SMD SOT-223 | | 1 | THT momentary switch | 2 pin THT 6 mm | | 1 | 100 kΩ resistor | SMD 1206 Only for trackpoint | | 1 | 2.2 uF capacitor | SMD 1206 Only for trackpoint | | 1 | Trackpoint module | R61 recommended, Only for.. well..|

Build instructions

Soldering

The soldering is pretty straight forward and it should be obvious what component goes where. If you haven't soldered SMD components before I recommend watching a youtube tutorial or two beforehand. I suggest adding a bit of solder to the middle pad for the battery holder.

Flashing wireless modules

The following instructions is for using an ST-Link V2 clone and Windows.

1. Download and install OpenOCD from https://openocd.org/ and drivers for the programmer from https://www.st.com/en/development-tools/stsw-link009.html

2. Create a file called 'openocd.cfg' in the bin folder where you installed OpenOCD with the following content:

    #nRF51822 Target
    source [find interface/stlink-v2.cfg]
   
    transport select hla_swd
   
    set WORKAREASIZE 0x4000
    source [find target/nrf51.cfg]
   

3. Copy the relevant firmware .bin file to the bin folder where you installed OpenOCD

4. Connect the 4 pins SWCLK, SWDIO, GND and 3.3 V on the ST-Link V2 to the matching pad on the PCB and the ST-Link to the computer

5. Open a command prompt, navigate to the bin folder mentioned above and enter:

    openocd.exe -f openocd.cfg
    
   

6. Open another command prompt and enter:

    telnet localhost 4444
   

You should now be connected to the programmer. Enter the following commands to flash the firmware:

halt
nrf51 mass_erase
program <firmware_file_name>.bin
reset

That's it! You should now have a working pierce keyboard.

Plates

These need some work

I have included files to 3D print bottom plates and switch plates (only for alps for now). The idea of the screwless bottom plates is to use a friction fit, but I'm not sure how well the current version fits.