Cottages and camps
A power wall built over the years, a generator in the shed and a fridge full of food. See it all from town.
- Budget and mixed-brand gear
- Flooded lead-acid or lithium banks
- Two-wire generator start
One controller for the gear you already own.
Origin89 reads the charge controller, inverter, batteries, probes and generator at your site, runs your rules there and keeps every reading with its age.
In active development. Not for sale yet.
Every bus.One board.Decisions stayon site.
Most off-grid walls grow one box at a time: a charge controller from one maker, an inverter from another, a meter, a generator in the shed. Nothing ties them together. The Controller wires into all of them and makes the site’s decisions on one 12 V board, with or without the internet.
3 × RS-485Modbus gear
CANBattery BMS
2 × VE.DirectMonitors, chargers
1-WireTemperature
4–20 mATank level
11 mAIdle, radio off
The copper behind this text is board A’s top layer, drawn from its Gerbers.
Who it’s for.
Anyone responsible for power at a place they can’t see from where they are.
Remote telecom shelters
Batteries, a genset and a tower hours from the nearest road. Know the site’s state before the truck leaves.
- Battery and generator state between visits
- Readings that show their age
- Rules that run without a link
Mining utilities
Gensets, pumps and battery banks spread across a site. Planned: several Controllers per location, in one account.
- One Controller per building or skid
- Local control stays with each unit
- Planned multi-location overview
Open from the board up.
The board files, Gerbers, bill of materials and firmware are public. Every part on this page has a designator you can look up: where it sits on the board, what it is and why it was chosen.
| U7 | STM32G0B1RET6 · LQFP-64 |
| U8 | ESP32-C6-WROOM-1-N8 |
| U3–U5 | MAX13487EESA+T · RS-485 |
| U9 | FM24W256 · FRAM |
- A-01100 × 125 mm, 1.6 mm FR-4. The board is the master dimension; the enclosure is printed around it.
- A-15No copper on any layer under the ESP32 module’s antenna keep-out.
- A-24The 1-Wire supply leaves the board on field cable, so it gets its own 100 mA fuse. A chewed probe cable can’t take the Controller down.
The budget is about 256 KB, not 512. Dual-bank A/B updates keep the new image in one half while the other holds the one it replaces.
binary 67,696 B25 % of one slot
Every terminal, named.
Pluggable screw terminals for field wiring, keyed headers for VE.Direct and the generator link. Point at a terminal to see what it connects to, its pins and its limits.
Point at or tap a terminal
Dual-MCU architecture.
Two processors. One of them decides.
The usual site monitor is one Linux computer. Networking, the web interface and the generator logic share its operating system. Origin89 splits the job: a microcontroller that only reads, decides and records, and a separate radio module that only talks. A Wi-Fi fault can’t take the generator rule with it.
Victron Cerbo GX: Venus OS, a Linux distribution, on a dual-core processor. Home Assistant Green: a quad-core Rockchip RK3566. SolarAssistant: a Raspberry Pi. Checked against their makers’ pages on 16 September 2026.
Every decision, all timing, all storage, all actuation.
U7 · STM32G0B1RET6 · Arm Cortex-M0+ · 512 KB flash in two banks
- U3–U6Reads the buses. Three RS-485 transceivers, the CAN transceiver, both VE.Direct ports, 1-Wire and the sense inputs.
- U9 U10Keeps the record. State in FRAM, the event log in 128 Mbit NOR flash.
- X2Keeps time. A 32.768 kHz crystal with a backup cell, so the log’s timeline survives a power loss.
- CN9Asks the generator to run. RUN and a regular KICK to board B, whose watchdog opens the contact if they stop.
- V3V3_ESPPowers the radio. It switches the ESP32’s rail, so a stuck radio restarts without a site visit. With that rail off, the board idles at 11 mA.
Runs unchanged if the ESP32 is unplugged. The rules, the record and the generator link never depend on the radio.
Carries the data. Decides nothing.
U8 · ESP32-C6-WROOM-1-N8 · RISC-V · 2.4 GHz Wi-Fi 6 and Bluetooth LE
- BLESetup from your phone. Pairing and provisioning over Bluetooth LE.
- Wi-FiSync when there’s a connection. Readings and events go to the app and the account when the site is online.
- OTADelivers updates. It carries a new firmware image; the STM32 decides whether to take it.
- No stateHolds no configuration. It frames and forwards. If it knew what a generator was, there would be two sources of truth.
One wire format, compiled twice. Both processors talk over a UART with hardware flow control, using the same KM43 framing, checksum and authentication from one Rust crate.
Wires into what’s already on the wall.
Runs on almost nothing.
One fused circuit on the battery bank. No inverter has to stay on to keep it awake.
38mA
0.50 W · Wi-Fi and Bluetooth on
Origin89, per day0.91 Ah
Cerbo GX MK2, per day5.1 Ah
Both at 13.1 V. Origin89: first bench readings on board revision A. Cerbo GX MK2: 2.8 W from Victron’s datasheet.
Not locked in.
Your site’s data is yours. The Controller speaks KM43, an open protocol with a public specification and published libraries. Keep the safety rules on the Controller and automate everything else wherever you already do.
- Home AssistantReadings as sensors, generator requests as actions.Planned
- SmartThingsSite state inside your routines.Planned
- MQTTkm43/<device_id>/txSpecified in KM43
- Local WebSocketThe app’s own API, on your network.Specified in KM43
- Rustkm43 0.1.0 · crates.ioPublished
- TypeScript@origin89/km43 0.1.1 · npmPublished
When rises above 7 °C for , .
- Runs on
- Controller
- Without internet
- Decides offline
- Status
- Core design
- Reads from
- 1-Wire probe on CN8. The Controller decides at the site and sends the notification when it has a connection.
import { MessageType, Quality } from "@origin89/km43";
// Follow the Controller’s event stream,
// and never act on an old or missing value.
send({ type: MessageType.Subscribe });
onReading((r) => {
if (r.quality === Quality.Stale) return;
if (r.quality === Quality.Absent) return;
publish("site/fridge_shelf", r.value);
});
The enums are real, from @origin89/km43. send, onReading and publish stand in for your own code.
How it compares.
The difference is in how it’s built. A microcontroller decides without an operating system to boot, the radio can fail without taking the rules with it, and the generator contact opens by itself if the Controller stops.
| Feature | Origin89 Controller | Victron Cerbo GX MK2 | SolarAssistant | Home Assistant, DIY |
|---|---|---|---|---|
| Built to keep running | ||||
| Control and networking | On separate chipsA microcontroller decides; a radio module only talks, so a Wi-Fi fault can’t stop the rules | One Linux computerVenus OS runs networking, the display and generator control on one dual-core processor | One Raspberry PiLinux-based image | One Linux computerHome Assistant OS; HA Green uses a quad-core RK3566 |
| After a power cut | No operating system to bootThe firmware runs directly on the microcontroller; start-up time not yet measured | Linux boots firstAbout 2 to 2.5 min, as reported on Victron’s community forum | Linux boots firstTime not stated | A few minutesUp to 5 min, per Home Assistant support |
| If the controller stops | The generator contact opens by itselfA hardware watchdog on the generator board opens two relays in series, 4.3 s after the last kick on the bench | Not documentedIts watchdog restarts the computer; no documented interlock on the generator relay | Not stated | Depends on your relay and automation |
| Temperature rating | Parts rated −40 to +85 °CController board. Generator board relays: −25 to +65 °C. Product rating pending testing | −20 to +50 °C | 0 to 50 °CRaspberry Pi 4 board | 0 to 40 °CIndoor use only |
| Idle draw | About 0.5 WUnder a fifth of a Cerbo GX. 38 mA at 13.1 V with Wi-Fi and Bluetooth on; 11 mA with the radio off. First bench readings | 2.8 WAt 12 V, without the GX Touch display | Not statedA Raspberry Pi board | About 1.7 WHA Green at 12 V, plus adapters |
| Connects to | ||||
| Mixed-brand gear | Designed for itEach model verified before it’s listed | Victron-firstSome third-party PV inverters and CAN batteries | 20+ inverter brandsEPEver and Renogy not supported | AnythingIf you write the integration |
| RS-485 | 3 ports, one bus each | USB adapter | USB adapter per device | DIY adapters |
| CAN and VE.Direct | 1 × CAN, 2 × VE.Direct | 2 × VE.Can, 3 × VE.Direct | USB adapter per device | DIY |
| Temperature probes | 1-Wire probes on one cable | 4 inputsVictron sensors | BMS-reported only | DIY with ESPHome |
| Tank level | 4–20 mA input | 4 resistive inputs4–20 mA through the GX Tank 140 add-on | Not stated | DIY |
| Generator start | Two-wire startOn its own generator board | Built-in relayState of charge, voltage, load and quiet hours | Not stated | DIY relay and automation |
| Decides with no internet | Yes | Yes | Monitoring yesOffline rules not stated | Yes |
| Open and available | ||||
| Open source | Firmware and board files | PartlyParts of Venus OS; no hardware files | No | Software yesHardware varies |
| Availability | In active development, not for sale yet | Shipping | Shipping | Shipping |
Checked on 17 September 2026 against Victron’s Cerbo GX datasheet, GX manual and developer wiki; SolarAssistant’s documentation and supported-inverter list; the Raspberry Pi 4 product brief; Home Assistant Green’s specifications and support pages; and the datasheets of the Controller’s parts. The Cerbo’s boot time comes from Victron’s community forum, not an official figure. The Origin89 column comes from the revision A design files; temperature figures are part ratings, the idle draw and the generator watchdog timing are bench readings and other values are not yet measured. Corrections welcome at hello@origin89.com.
Sample siteCottage
Controller onlineBattery bank12.62 V8 s ago
RS-485 1
RS-485 1
Solar charging18.4 A8 s ago
RS-485 1
RS-485 1
Fridge, middle shelf3.8 °C41 s ago
1-Wire
1-Wire
Outdoor air−4.2 °C14 min ago
1-Wire
1-Wire
Propane tankNo reading since 06:10TNK
Generator rule Starts below 11.9 V, runs at least 45 min, never between 22:00 and 07:00.
Your site, wherever you are.
The Offgrid app shows what the Controller reads and what it decided, each value with the time it was taken. When the site is offline, you see the last reading and its age, never a number that only looks fresh.
- Stale looks staleA reading past its interval is marked, and a missing one says so.
- Requests go through the rulesAsk for the generator from the app; the Controller’s rules decide whether it runs.
- History stays on the siteThe Controller keeps the event log and syncs it when there’s a connection.
- Several locationsPlanned: one account for every Controller you look after, grouped by site.
The app is in development. Screens and readings here are samples.
Why did the generator start at 5:40?
The charge controller reported the battery bank at 11.84 V at 05:38. That’s under your 11.9 V start rule, so the Controller asked the generator box to run.
The outdoor probe hasn’t reported for 14 minutes, so I left it out.
RS-485 1 · 11.84 V · 05:38Rule · start below 11.9 V1-Wire · outdoor · 14 min old
Is the fridge okay?
Yes. The middle shelf read 3.8 °C 41 seconds ago, and it has stayed between 3 and 5 °C since last night.
Buddy explains what changed.
Ask in plain words. Buddy answers from the site’s own readings and rules, says where each number came from and how old it is, and leaves out what it can’t trust.
Buddy only advises. It can’t start, stop or switch anything. Only the Controller’s rules act on equipment.
Technical specifications
From the revision A design files, exported 9 September 2026. Values marked in amber wait on bench measurement.
On the benchBoard revision A · updated 17 September 2026
- Idle draw11 mA radio off, 38 mA with Wi-Fi and Bluetooth, at 13.1 V
- Generator watchdog timing4.34 to 4.46 s after the last kick
- 1-Wire probes per busPlus the longest outdoor run (pending)
- Start-battery accuracySNS calibration against a meter (pending)
- Wi-Fi range in the enclosureThrough the closed cover (pending)
- RS-485 with three busesAll three ports talking at once (pending)
Processors
- Controller
- STM32G0B1RET6, Arm Cortex-M0+, 512 KB flash in two banks
- Radio
- ESP32-C6-WROOM-1-N8, RISC-V
- Link
- UART with hardware flow control
- Radio power
- Switched by the controller
Field buses
- RS-485
- 3 ports, MAX13487E, SM712 surge clamp, 120 Ω termination on a jumper, 560 Ω fail-safe bias
- CAN
- 1 port, TJA1051T/3, PESD1CAN clamp, 120 Ω on a jumper
- VE.Direct
- 2 ports, JST PH 4-pin
- Terminals
- Pluggable screw, 3.5 mm pitch
Sensing
- 1-Wire
- 3.3 V probe supply through a 100 mA resettable fuse, ESD clamp
- Probes per bus
- Pending bench test
- SNS
- Start-battery voltage, about 36 V full scale by design
- TNK
- 4–20 mA, 150 Ω sense
- SEL
- Panel selector input
Power
- Input
- 12 V DC, straight from the battery bank
- Protection
- SMBJ18A clamp, 2 A resettable fuse, reverse polarity
- Regulators
- 2 × TPS54331 bucks, 5 V and 3.3 V
- Idle, radio on
- 38 mA at 13.1 V, about 0.5 W, Wi-Fi and Bluetooth on
- Idle, radio off
- 11 mA at 13.1 V, about 0.14 W, ESP32 rail switched off
- Source
- First bench readings, board revision A
Generator board
- Contact
- Two G5V-2 relays in series, gold-clad contacts
- Watchdog
- Hardware timer, opens 4.3 s after the kicks stop, measured
- Output
- Dry contact, 30 V DC max, 2 A fuse, SMBJ30CA clamp
- Link
- JST VH 5-pin to the Controller
- Status
- Interlock proven on the bench, 17 September 2026
Wireless
- Wi-Fi
- 2.4 GHz Wi-Fi 6
- Bluetooth
- Bluetooth LE, for setup
- Antenna
- On the module, under the cover
- Range in the enclosure
- Pending bench test
Storage and time
- State
- FM24W256 FRAM, 256 kbit
- Event log
- W25Q128JV NOR flash, 128 Mbit
- Clock
- 32.768 kHz crystal, ±20 ppm, backup cell input
Board
- Size
- 100 × 125 mm
- Stack
- 4 layers, 1.6 mm FR-4, solid ground plane under every pair
- Finish
- ENIG, green mask, white silkscreen
- Revision
- A, fabricated, bench measurements in progress
Enclosure
- Face
- 132 × 157 mm, 40 mm off the wall
- With ears
- 160 × 157 mm
- Indicator
- One status light
- Build
- Printed around the finished board
Software and files
- Firmware
- Rust, one image per processor
- Protocol
- KM43, shared by both processors
- Hardware
- Board projects, Gerbers, BOM and enclosure CAD in origin89hq/hardware
Notes from the bench.
Bench results and progress on the Controller, posted as we go.
Board A on the bench: the first four days
Two unattended nights on the first Controller board: one bad reply in 58 169 Modbus polls, a working Wi-Fi link, and the tests still to run.
Why the generator start has its own board
The Controller's main board never closes the generator's start contact itself. A second board with two relays, a hardware watchdog and no firmware does, and only while the controller keeps asking. It now holds and drops on the bench, 4.3 s after the last kick.
Why we started Origin89
An off-grid cabin at km 43 in Québec, solar gear and a generator from different makers, and no monitoring that worked with all of it.
Be first on the wall.
We’ll write when bench results are in and again when boards can be reserved. Nothing else.
We’ll email you a link to confirm your address.