People are normally using MCU boards for their low cost, low-power consumption, low price and/or real-time ability. The Raspberry Pi Pico is no exception, but if you don’t care about using a large board, Waveshare created a 177 x 62 mm “expander” board for the Raspberry Pi Pico that can take four modules.
The company’s Quad GPIO Expander board includes a set of female headers for RPi Pico, and four sets of 2×20 male headers for extra modules that bring support for 14500 batteries, OLED displays, RTC, relays, and other compatible modules.
The expansion board also has a Micro USB port for power, and to leave the Micro USB OTG port on the Raspberry Pi Pico for other purposes. Each header pin is clearly labeled, which could be useful if using some of the pins with jumper wires instead of modules.
Waveshare has hundreds of different modules and somehow decided not to clearly list the ones that are compatible with the Quad GPIO expander board… But after some research, we can see the modules inserted above include:
- A UPS Module for Raspberry Pi Pico that can take a 18650 battery and featuring an I2C interface for battery level monitoring ($14.99 without battery)
- An unknown relay module
- An RTC Module For Raspberry Pi Pico based on DS3231 chip. Takes a CR2012 coin-cell battery. ($8.99 without battery)
- An unknown e-paper display module
Further research shows some Raspberry Pi Pico modules in the accessories part of the Wiki.
We can also see some ePaper, LCD and OLED displays, an IMU sensor, an NB-IoT modem, and that’s about it. I suppose any module that follows the Raspberry Pi Pico layout should work. Just make sure the interface used don’t conflict with each other.
The Quad GPIO Expander for Raspberry Pi Pico can be purchased on Waveshare store, or Seeed Studio with the latter also selling some of the compatible modules on the page, including the UPS module, LCD & OLED display modules, and the RTC module.