Big Poppa isn’t just the name of one of music’s greatest rappers. It’s also the name of a new Raspberry Pi board. The big p4ppa is a Raspberry Pi five-channel PWM, PT100 and ADXL345 board that works on any Pi 2/3/4. Created by Greg’s Tinker Town, the board was originally developed as a solution to help control 3D printer fans. Designed for low-power accessories, it works with fans but isn’t made for heavy loads or heaters.
The big p4ppa’s features include:
- A 5V input to power the Pi via the board itself. Note – you cannot connect other power sources (USB, PoE HAT, battery backup HAT) to the Pi when using the board.
- Five PWM outputs (via MOSFETs with external flyback diodes)
- Independent voltages for each fan – 5V or anything up to 24V
- Cutout for an optional 25mmx25mm fan to cool the Pi
- Support for Adafruit's PT100 amplifier board or a PT100 StepStick (available on AliExpress)
- Convenient header for an ADXL345 accelerometer to measure resonance in Klipper
So, how do you use it? To power a fan, you place a jumper on the appropriate voltage for each fan and connect the 5V and ground. You then connect any other voltage rails you intend to use. The board can support voltages as high as 24V. After that, you control the fans using the GPIO’s as printed on the circuit board.
Though the board is quite steady, standoffs are recommended for extra security, especially if using the Adafruit board. The input header can support a 2x3 or 2x4 pin header. The 2x4 header can accommodate previously designed 2x4 headers that plug directly into the Raspberry Pi header. The two 3V3 pins are linked to power the ADXL345.
Big p4ppa’s design is fully open-sourced, so if you have the patience, the know-how, and the tools, you can build this yourself. But if you lack any of those things, the board is also available as a kit or fully assembled. The kit comes with everything you need to build a big p4ppa, including PCB with SMT components, five 6-pin header and five jumpers (for selecting voltages on the 5 fans), a 8-pin headers (ADXL345 by breaking header in half), three 8-pin female header, and a 40-pin Pi header. Keep in mind that you’ll have to do the soldering yourself.