Bit Cookie's SI-GRID Is a 32-Pin, Expandable, Crosspoint Switch for Almost Any Signal Type
An Analog Devices AD75019 sits at the heart of this clever general-purpose switch, with an Espressif ESP32 providing Wi-Fi control.
Beijing-based Bit Cookie is preparing to launch a gadget designed to allow you to route 32 pins in any way you desire — creating user-defined interconnects across a 16×16 endpoint grid: the SI-GRID.
"SI-GRID is a signal matrix that you can reprogram at will. It can simultaneously create arbitrary interconnects — any node count, any topology — across 32 pins, for both analog and digital signals," its creators explain. "Think of it as an Ethernet switch for any signal type, that works with standards including SPI, I2C, JTAG, and GPIO [General-Purpose Input/Output]. It dynamically creates any connection pattern you want across a 16×16 grid of signal endpoints, enabling arbitrary interconnects among any number of nodes—point-to-point, one-to-many, or many-to-many, on demand. In short, SI-GRID is a shape-shifter for your lab. Bring your ideas: how you configure it is entirely up to you."
The board is based around the Analog Devices AD75019, a 16×16 crosspoint switch array with a total of 256 switches, controlled over a serial input. In the Bit Cookie, it's linked to 32 pins supporting a signal level of -12–12V — and the board supports the AD75019's serial output, allowing multiple boards to be daisy-chained together to create larger matrices.
A daughterboard built around an Espressif ESP32-PICO-D4 controls the Bit Cookie, though the board can also be used directly as a secondary device connected to an existing control system, and comes complete with a custom firmware for reprogramming the switch matrix over Wi-Fi — though a command-line interface is also available for scripting and system integration, the company promises. Control happens over what the company says is an "SPI-like host protocol," and there's support for customizing the firmware through either Espressif ESP-IDF or the Arduino IDE.
"SI-GRID is open source and we hope to release a number of files related to its design," the company says of its plans post-crowdfunding. "Its board schematics will be made available as a PDF, with board layout Gerber files and manufacturing notes and bill of materials released alongside. Moreover its firmware, either as a precompiled binary or source will be available; similarly its companion software will also be made open source. Finally, we plan on making lots of sample code available to people, so using SI-GRID will be as straightforward as possible."
Bit Cookie is planning to launch a crowdfunding campaign for the SI-GRID in the near future, with interested parties invited to sign up on Crowd Supply to be notified when it goes live.