Switchback now has a full detail page. Eight relay outputs and eight Picket-format digital inputs on a single off-the-shelf module, documented end to end. With firmware already in the web flasher and the board pre-housed by the manufacturer, this is the fastest module on the platform to get from "I want one" to "it's running on the bus."
What's on the page
Same structure as Headwaters, Bearing, Peregrine, Reservoir, and Solstice before it. A complete bill of materials, every part called out by name and quantity. A wiring diagram pulled from the firmware repo. Hardware section that breaks down the MCU, power, the eight relays, the eight digital inputs, the CAN interface, and the WiFi/Ethernet stack. A step-by-step assembly walkthrough that takes you from "pick an address" to "Headwaters discovers it on the bus." Full CAN protocol reference for the OTA trigger, WiFi config chunked protocol, digital input broadcast, relay toggle, and relay status broadcast.
What makes Switchback different
Switchback is the first module on the platform with no 3D printed enclosure. The Waveshare ESP32-S3-ETH-8DI-8RO-C ships in a finished plastic case with four corner mounting holes (4.5 mm, fits M4 machine screws or #8 wood screws cleanly). You skip the printer entirely. Mount it to a wall, the floor of an equipment bay, or any flat surface, and wire the screw terminals. That changes the build flow: no print profile, no STL files, no orthographic drawings, no assembly animation. Just flash, mount, wire.
The other thing that makes Switchback different is that it does two jobs at once. The eight relay channels handle high-current loads, pumps, fans, awning motors, slide-out actuators, exterior lighting, up to 10 A per channel at 250 V AC or 30 V DC. The eight digital inputs broadcast in the Picket message format, byte-for-byte identical to a real Picket module, so Headwaters decodes them through the same path. If you already have a Switchback running for relay control, you get eight Picket-style cabinet or door sensors for free in the same enclosure.
The high-voltage section
Switchback is the first module on the platform that can switch mains AC, so the detail page leads with a red caution callout right under the hero, before the product overview. AC mains and high-current DC circuits can shock, burn, or start fires. If you are not comfortable wiring those, hire a qualified electrician. Always disconnect power at the source before working on the relay terminals, install fuses or breakers sized below the relay rating on every load circuit, and verify your work with a meter before energizing.
The same callout includes the formal liability disclaimer: every TrailCurrent design and document on the site is published for educational purposes only, provided "AS IS" and "AS AVAILABLE," with no warranty against improper installation. You assume responsibility for verifying suitability, complying with applicable codes, and obtaining any required permits. We've always operated that way, but with mains-rated relays in scope it's worth saying out loud, in writing, on the page.
Multi-instance, like Torrent
Up to three Switchback modules can share one CAN bus. Each is built with a unique SWITCHBACK_ADDRESS (0, 1, or 2) that offsets every CAN ID, so a galley Switchback at address 0 and a cargo-bay Switchback at address 1 don't step on each other's traffic. The web flasher already lists all three address variants in the Switchback dropdown, and the matching paired Tapper variants are there too. Pick the address before you flash, then plug it in.
Already in the flasher
If you have a board on the bench right now, the fastest path is the web flasher. Pick Switchback from the module list, pick the address variant, plug in USB-C, click flash. The full source for the firmware is in the Switchback repo on GitHub if you want to fork it. The board itself is on Waveshare directly: ESP32-S3-ETH-8DI-8RO-C.
If you want a deeper read first, the detail page has everything you need: BOM, hardware breakdown, full assembly walkthrough, and the CAN protocol reference, all in one place.