RPi Stepper Driver HAT Comes Equipped with a 10-30VDC to 5VDC Step-Down Converter
The $1 HAT features a step-down converter built into the PCB, along with pinouts for eight LEDs and a trio of JST XH connectors for GPIOs.
Switzerland-based engineering student Schmid Lukas created a vending machine that was driven by a NEMA17 stepper motor, but the PCB he using was not up to par, so he decided to design his own. What he came up with was the Raspberry Pi 3 Stepper Motor Driver HAT. The tiny board featured pinouts for eight LEDs and a pair of JST XH connectors to connect inputs directly to the Pi.
Lukas has since revised the original board to include a step-down converter to run stepper motors at a higher voltage, and simultaneously run the Pi at the same time at 5V DC. As he explains, "It's a two in one stepper driver HAT and step-down converter. Simply power motor and driver at a higher voltage like 24VDC and let the onboard step-down converter supply the 5VDC for the Raspberry Pi."
The RPi stepper driver HAT is a simple, but streamlined design, and is outfitted with a single barrel jack for power input, step-down convertor (10-30V DC to 5V DC), and on/off switch. It packs a single JST XH-4A for a four-wire connection to a stepper motor and a trio of JST XH-3A connectors for GPIOs (5V, GND, GPIO) as well. There are also pin headers for 5V and GND, pin headers and resistor-array for LEDs, and a socket for a DRV8825 or a 4988 stepper driver.
On the voltage end, the RPi stepper driver HAT provides input voltage at 10-30V DC, the output voltage at 5V DC (for Raspberry Pi), and the stepper driver voltage at the same 10-30V DC as the input. Lukas is offering the RPi Stepper Driver HAT on his Tindie page for $1, which gets you the PCB only, $3 for the full kit, and $5 for full assembly.