Sequent's 8-MOSFET Switches Up to 64 High-Voltage, High-Current DC Loads on a Single Raspberry Pi
Stackable board design allows for expansion in groups of eight up to 64 MOSFETs per Raspberry Pi, and includes two DIN mount options.
UPDATE (11/13/2020): Sequent Microsystems has officially launched the crowdfunding campaign for its latest Raspberry Pi add-on, a stackable DIN-rail mountable solid-state power driver offering eight MOSFETs per unit and up to eight units per stack.
The campaign, now live, prices the 8-MOSFET add-ons at $30 early bird or $35 regular pricing, with discounts for larger volume orders; optional accessories include an adapter board offering compatibility with microcontrollers including the Arduino Nano and Uno, Teensy, ESP32, and Adafruit Feather range and two DIN-rail mounting kits, all priced at $10 each.
Full details are available on the Crowd Supply campaign page.
Original article continues below.
Sequent Microsystems is preparing to launch another add-on board for the Raspberry Pi family of single-board computers (SBCs) — or anything capable of talking I2C; this time offering the ability to switch up to 64 DC loads at voltages as high as 250V from a single Raspberry Pi.
Sequent has a history of building stackable boards designed to expand the Raspberry Pi and compatibles: Two months ago the company unveiled the Mega-RTD HAT to offer connectivity to up to 64 resistance temperature detector (RTD) devices, and earlier in the year launched a 32-relay switching board with the promise of a 64-relay variant to follow. Now, it's back — and this time it's connecting up to 64 DC loads at up to 250V to a single Raspberry Pi.
"When looking to drive high loads with a microprocessor, hardware designers typically turn to relays, in part because relatively inexpensive relays are still quite reliable under most circumstances," explains Sequent's Mihai Beffa. "While they tend to perform well under AC loads, however, they fall short when faced with high DC voltages, fast switching times, and endurance requirements. Which is where 8-MOSFET comes in."
Switching from relays to MOSFETs now only brings support for higher DC voltages, Sequent claims, but also offers switching times as low as 0.1ms and high endurance. The basic eight-module board can drive four 24V loads at 10A, and another four 240V loads at 2A — simultaneously.
"8-MOSFET employs industrial-grade, pluggable connectors that facilitate field installation and debugging. Status LEDs show when MOSFETs are on or off," Beffa adds. "And it’s scalable. Up to eight cards can be stacked on top of a single Raspberry Pi, giving your Pi the ability to drive up to 64 loads. And, because 8-MOSFET only occupies the I2C, you’ll still have 24 GPIO pins to use for other applications."
More details on the board, including its two DIN-rail mount configurations and its compatibility with other devices capable of speaking I2C, can be found on Crowd Supply along with a form to fill to be notified when the campaign goes live.