Witty Pi 4
The Witty Pi 4 ($27.63) from UUGear is a great solution for all your Raspberry Pi timing, scheduling, and power management needs. No longer will you need to worry about the accuracy of your Raspberry Pi clock thanks to the on-board real-time clock and temperature sensor that allows for additional accuracy and temperature compensation. And anyone who has worked with the Raspberry Pi knows about power management and the relatively difficult nature of powering your Raspberry Pi on or off, and this is where the Witty Pi really shines.
Unlike a microcontroller that you simply power-off, you need to go through a powering-off sequence with your Raspberry Pi, similar to your desktop computer. And the Witty Pi can do that too! Now your Raspberry Pi can shut down and only wake up when needed, saving lots of power. If you have a remote monitoring project, or one that runs off battery power, the Witty Pi should be something to consider adding to the build.
9/10 Great addition to a Raspberry Pi.
Adafruit Feather RP2040 with RFM95 LoRa Radio
The Adafruit Feather RP2040 RFM95 LoRa Radio board ($29.95), aka ‘RadioFruits’, is Adafruit’s take on a microcontroller with integrated long-range (LoRa) packet radio transceiver, along with a built-in USB and battery charging system. This is the perfect microcontroller board for creating wireless sensors that have a longer range and require less power than other wireless solutions like Bluetooth.
The board features an RP2040 chip running at 133MHz, the same as you can find on a Raspberry Pi Pico. You also get a generous 8MB of on-board QSPI flash and 264kB of RAM, plus on-board RGB LED, STEMMA QT connector, and lots of GPIO pins. Between the on-board battery management, LoRa radio, and RP2040, it would be hard to beat this little board for creating an outdoor sensor network.
Simple long-range sensing.