The Raspberry Pi Pico just hit the shelves last month, which means purpose-built hardware for the board is still very limited. You certainly don’t need Arduino shield-style boards to use your Pico, because it is already a development board that you can connect directly to hardware components or use with a breadboard. But add-on boards can provide a lot of convenience and can help you avoid a rat’s nest of wires on a breadboard. To give you more hardware to work with when prototyping projects, Hammond designed the Kiwikit expanded development board for the Raspberry Pi Pico.
In his write-up, Hammond refers to the Raspberry Pi Pico as a “module.” That is a bit of a misnomer, as the Pico is a microcontroller development board just like an Arduino Uno or Adafruit Feather. But Hammond is correct that you can’t really do much with a Pico unless you connect some additional hardware. The Kiwikit gives you a handful of built-in hardware to work with so you have a jumping-off point for your prototypes. To use it, you simply solder header pins onto your Raspberry Pi Pico and then plug it into the Kiwikit. With the right libraries and code, you can then work with any of the hardware components that are built into the board.
Kiwikit gives you quick and easy access to the following hardware: two general purpose LEDs that can be controlled by the user, a power indicator LED, three general purpose buttons, a reset button, an SSD1306-based OLED screen, a small AT24C08 EEPROM chip that can be used in addition to the Pico’s flash memory, an LDR (Light-Dependent Resistor) connected to an analog input pin, breakouts for SPI, breakouts for I2C, breakouts for the other GPIO pins, and breakouts for power. The Kiwikit board was designed in KiCAD and then manufactured by JLCPCB. Hammond received his PCBs and assembled a unit to verify that everything worked, and didn’t find any major issues. If you’d like to build your own Kiwikit board, the PCB files are on Hammond’s GitHub page so you can have them fabricated by whatever PCB house you prefer.