Overview

One box — readable right on site

Decoding, display and logging all happen inside the box, so checking an engine RPM never takes a round trip to the cloud. Plug in a monitor and it is a dashboard; enable the tunnel only when you need remote access.

27Decoded parameters
3 sGauge refresh interval
15 MbpsKernel-mode tunnel, measured
1.3Typical load average (quad-core)
0Cloud dependencies

Applications

Five deployments, one box

The first three scenarios run the same decoding core — the only difference is which bus you tap. Switching protocol is one button press, and the gauge layout follows automatically, so nobody on site has to configure a screen.

Vessel navigation monitoring

NMEA 2000

Tap the ship's N2K backbone and bring speed, heading, depth and engine RPM onto a single screen. GPS runs on its own serial port, so satellite data is unaffected by bus load.

  • Speed over ground and through water, course over ground and heading (compass gauge, continuous through north)
  • Depth alarm: the whole gauge turns red and pulses slowly below the configured limit
  • Engine RPM, battery voltage, charge/discharge current, latitude and longitude
  • Can be forwarded into Signal K for full instruments and charts on a phone
10 parameters measured · SOG 4.47 kn · COG 47.97° · Depth 9.8 m
1150 rpm · Battery 12.4 V

Heavy equipment & engine monitoring

J1939

The diagnostic language shared by diesel engines, construction machinery and generator sets. Coolant temperature, oil pressure, fuel and engine hours at a glance — fit for fleet management and preventive maintenance.

  • Engine RPM, coolant and fuel temperature, boost pressure
  • Low oil pressure or high coolant temperature switches to a warning color immediately
  • Fuel level and live consumption, enough to estimate remaining runtime
  • Cumulative engine hours as the basis for service scheduling
11 parameters measured · 975 rpm · Coolant 80 °C · Oil press. 260 kPa
10.85 L/h · Hours 1234.5 · Battery 24.8 V

Agricultural operation monitoring

J1939 / ISOBUS

A tractor's engine side is identical to heavy equipment; plus the extra parameters that only agricultural work uses. When the system detects a PTO signal it switches to the agricultural layout by itself — no manual selection.

  • PTO shaft speed and oil temperature — the key figure during implement work, so it is promoted to the primary gauge
  • Wheel speed and ground speed measured separately — the difference is slip
  • Slip ratio: the share of tractive effort wasted digging into soil; warns above 15 %
  • Engine hours and fuel consumption, aligned with operating-hour management
15 parameters measured · PTO 828 rpm · Slip 1.13 %
Wheel 8.86 / Ground 8.76 km/h · Hours 1234.5

Network egress node

VPN / obfuscation

At sea or at cross-border sites where network access is restricted, traffic from the vessel or the job site leaves through a tunnel that is hard to fingerprint. If the tunnel drops, blocking is enforced by routing topology — it never falls back to plaintext.

  • AmneziaWG kernel-mode tunnel with tunable packet signature (Jc / S1 / S2 / H1–H4)
  • Hysteria 2 with salamander obfuscation, suited to high-latency links
  • One-touch network modes: direct / full VPN / hotspot / router
  • Fail-closed guaranteed by routing topology, not by firewall rules alone
Kernel-mode tunnel 15 Mbps (userspace implementation: 8.4 Mbps)
Zero packet leakage measured when the tunnel drops

On-site operations terminal

HDMI / Web

Plug in a monitor and you have a dashboard — no laptop needed. When you need hands-on access, open a browser on your phone for a full terminal instead of hunting for a serial cable.

  • Boots straight into a full-screen dashboard — no login, no mouse required to operate
  • Switch which page the monitor shows from your phone's side menu
  • The web terminal supports multiple independent tabs
  • Plug in a USB NIC and it obtains an address and adjusts priority automatically
Display output 1280 × 720 @ 60 Hz · GPU-accelerated compositing
The panel itself has zero third-party dependencies — Python standard library only

Instrumentation

How the engine gauges are designed

Dials are drawn as vectors with no front-end framework, so they update smoothly even on a low-power processor. The design goal is "readable without memorizing numbers" — the information is encoded in shape and color.

0 1.5k 3k 1950 rpm Threshold bands Limits drawn on the dial — no numbers to memorize Scale numbers Range marks; estimate from needle position Peak marker Highest value seen in this period Needle and value arc Colour follows the thresholds automatically Trend line Direction over roughly the last minute Center reading Tabular figures — no horizontal jitter
Gauge anatomy diagram (not a device screenshot). The real screen shows 8–11 dials depending on the scenario, with the primary gauge at twice the area.
82 Normal · green 98 Caution · amber 109 Danger · red, pulsing
The same coolant-temperature gauge in three states. In danger the whole dial pulses slowly, so it registers in peripheral vision.

Threshold bands

Warning limits are drawn on the outer ring of the dial. You do not have to remember that "oil pressure below 150 is dangerous" — the needle entering the amber band tells you. Direction follows the meaning of the field: the red band sits at the low end for oil pressure, at the high end for coolant temperature.

Peak marker

A thin line on the dial marks the highest value seen during this period. How far the engine revved, how hot the coolant got — useful to look back on afterwards, and a standard feature on real engine instruments.

Trend line

Below the primary gauge, roughly the last minute is plotted. What matters is direction: is RPM climbing or steady, is coolant temperature creeping up — more telling than any single instantaneous value.

Clear hierarchy

The first item in each scenario is the primary gauge and takes twice the area: speed for vessels, engine RPM for heavy equipment, PTO speed for tractors — so a glance lands on what matters most first.

Compass for angles

Course and heading do not use an arc gauge. 0° and 360° are the same direction, so an arc needle snaps back to the start at due north and looks like a fault; a compass goes round continuously.

Range follows the scenario

Battery voltage is 10–15 V on a vessel (12 V system) and 20–30 V on heavy equipment (24 V system). Sharing one range would pin the needle to the edge forever, which conveys nothing.

Data Path

How a signal becomes a screen

Decoding finishes inside the box — no cloud round trip. The same decoded data feeds three destinations at once: local gauges, the Signal K ecosystem, and remote transport that is only enabled when you need it.

Sources CAN bus J1939 · NMEA 2000 GPS receiver NMEA 0183 · 9600 4G / WiFi / Ethernet Uplink Decoding core PGN decoder Raw SocketCAN reads Unit scaling · validity Stale after 15 s Outputs Local gauges HDMI full screen · phone Signal K (optional) KIP · charts · external apps Encrypted tunnel Remote monitoring (optional)
About Signal K: Signal K is the marine industry's standard data model and natively supports NMEA 2000 only. The box adds a bridging layer that converts decoded J1939 data into SI units before feeding it in (engine RPM → Hz, temperature → K, pressure → Pa), so heavy-equipment and tractor data can also enter the Signal K ecosystem for KIP, charts or third-party apps. It is, however, the most resource-hungry service on the box: it does not start at boot by default — turn it on from the panel when you need it.

Specification

Hardware & interfaces

ItemSpecificationNotes
Processori.MX6Q · quad-core · 792 MHzARM Cortex-A9
Memory1 GB~25 % in typical use
Storage3.6 GB eMMCSystem image ~2.2 GB
CAN1 port250 / 500 kbit/s, loopback self-test supported
GPSDedicated serial portNMEA 0183 · 9600 8N1
Display outputHDMI 720p60GPU-accelerated compositing
WirelessWiFi + BluetoothShared single antenna
ExpansionUSB · mPCIeAdd a NIC or 4G module

Resource use & thermals

The enclosure is sealed metal with passive cooling, which makes it worth laying out what each service costs. Measured values below — the difference comes mainly from whether Signal K is running.

ConfigurationLoad averageEnclosure temp.Detail
Local gauges (default)1.369.7 °CCAN decoding + dials + HDMI output
Signal K enabled2.978.3 °COnly needed for KIP / charts
Throttle threshold—95 °CCores begin clocking down
Protective shutdown—100 °C—

Feature status

FeatureStatusDetail
J1939 engine parameter decodingVERIFIEDConversions checked item by item under loopback
NMEA 2000 navigation parametersVERIFIEDAs above
PTO speed and oil temperatureVERIFIEDPGN 65091, per J1939-71
Wheel / ground speed and slipON-MACHINE CHECKISO 11783-7; byte layout to be confirmed on a real machine
Local gauges and dialsVERIFIEDIncluding bands, peak, trend and automatic layout
J1939 → Signal K bridgeVERIFIED11 parameters, SI conversion correct
Encrypted tunnelVERIFIEDHandshake succeeds, egress address changes
Display output & remote switchingVERIFIEDBoots into the dashboard automatically
Live bus connectionFIELD PENDINGVerified so far with loopback and simulated frames
Hotspot / router modeHW PENDINGRequires an external AP-capable NIC
About the verification method: the present figures were verified in loopback mode with spec-compliant simulated frames. That proves the decoding chain and unit conversions are correct, but it does not prove the byte positions are right on every machine model. Items marked for on-machine checking are defined in ISO 11783-7 and should be verified first when a real machine is available.

Ready

The signal is on site. So is the answer.

One box owns telemetry, display and connectivity: decoding stays on site, gauges do not depend on the network, and the tunnel comes up only when you need it — understanding what your equipment is doing without reaching for the cloud.

  • J1939 decoding
  • NMEA 2000 decoding
  • ISOBUS PTO
  • Local gauges
  • Signal K bridge
  • Anti-DPI tunnel

FAQ

CAN bus telemetry — common questions

What fleet operators, boat owners and OEM engineers usually ask about J1939, NMEA 2000 and Signal K.

Which J1939 and NMEA 2000 parameters does it decode?

27 parameters across J1939, NMEA 2000 and ISOBUS PTO: engine RPM, coolant and fuel temperature, oil pressure, boost pressure, fuel level and consumption, engine hours, battery voltage, plus speed, heading, depth and position on the marine side. Decoding and unit conversions are verified in loopback with spec-compliant frames; connection to a live vehicle bus is still pending field verification.

Can J1939 heavy-equipment data feed into Signal K?

Yes. Signal K natively accepts NMEA 2000 only, so the box adds a bridging layer that converts decoded J1939 data to SI units (rpm → Hz, °C → K, kPa → Pa) before feeding it in — 11 parameters verified so far. Because Signal K is the most resource-hungry service on the box, it stays off at boot and is enabled from the panel when needed.

Does engine monitoring work offline, without the cloud?

Yes. Decoding, gauges and logging all run inside the box — unplug the network and the HDMI dashboard and phone-browser gauges keep updating. Remote access through the encrypted tunnel is optional and only enabled when you need it, which suits vessels at sea and machinery on remote sites.