3D printer: live demo
degraded Pulse 59820323 · 2026-11-13T22:41:36Z · Monitoring only
A networked 3D printer. Its firmware owns heating, motion and thermal-runaway protection; HEART on the print server notices, explains and tells a person. HEART runs on the printer's host computer (a Raspberry Pi with OctoPrint or Klipper, or the printer's own Linux board), never in the firmware.
Next in its story: system.main-function-degraded in about 20 minutes.
What HEART Hub receives
Only the public Pulse and public alerts: the status and fault codes. Nothing else ever leaves the device.
| Status | degraded | public | |
| Printer | idle | public |
What stays on the device
The owner or clinic sees these locally with a key. They are never reported.
| Hotend | -38 Cel | internal | |
| Bed | 24 Cel | internal | |
| Stepper driver | 48.9 Cel | internal | |
| Job progress | 0 % | internal | |
| Filament left | 986 g | internal | |
| Wi-Fi | up | internal | |
| Job | none | private |
Alerts in the last hour
| Fault code | Severity | Status | Raised (UTC) | What HEART says |
|---|---|---|---|---|
sensors.out-of-rangeA reading is outside what is physically possible. | error | open | 22:41:05 | The hotend temperature reading is impossible. The hotend reads -38 Cel, which is impossible in this room: an open or shorted thermistor. The firmware will not heat until it reads sensibly. Check the thermistor connector. |
system.main-function-lostThe system cannot do its main job. Every HEART MUST be able to detect this. | critical | resolved 22:36:00 | 22:34:05 | The firmware has shut the heaters down. The printer's firmware cut the heaters by itself (thermal runaway: the reading fell while heating). The job was aborted. HEART only reports this: check the hotend before resetting the printer. |
system.main-function-lostThe system cannot do its main job. Every HEART MUST be able to detect this. | error | resolved 22:29:00 | 22:27:05 | Filament has run out: the print is paused. The run-out sensor stopped the print and the firmware parked the head, keeping the nozzle hot. Load a new spool and resume the job at the printer. |
actuators.position-mismatchIt ended up somewhere other than where it was told to go. | error | resolved 22:23:00 | 22:22:05 | A layer shift was detected. The X stepper driver reported stalls with current spikes: the head likely skipped steps. Check the print, the belts and pulleys. |
connectivity.link-lostA network link is down. | warning | resolved 22:19:00 | 22:16:05 | The printer's Wi-Fi link is down. Reports cannot be sent until the link is back. The printer keeps printing and its firmware keeps protecting it. |
sensors.stuckA reading has not changed when it should have. | error | resolved 22:13:30 | 22:12:05 | The bed temperature reading has stopped changing. The bed reading has sat at exactly 60.00 Cel for 30 s. A live thermistor always jitters a little. The firmware still sees a temperature at target, so it will not notice. Check the bed thermistor and its cable. |
performance.too-hotThe device is overheating and may slow itself down. | warning | resolved 22:10:00 | 22:08:05 | A stepper driver is too hot. The stepper driver heatsink is above 80 Cel. Its fan may have stopped. Hot drivers cut their current and can skip steps. |
system.main-function-degradedThe main job works, but less well than normal. | warning | resolved 22:05:18 | 22:02:05 | The hotend is heating far more slowly than normal. Heating for over 120 s and the hotend is far below its 210 Cel target (normally about 80 s). A weak heater cartridge, a loose connection or a missing silicone sock. |
sensors.out-of-rangeA reading is outside what is physically possible. | error | resolved 21:42:00 | 21:41:05 | The hotend temperature reading is impossible. The hotend reads -38 Cel, which is impossible in this room: an open or shorted thermistor. The firmware will not heat until it reads sensibly. Check the thermistor connector. |
Now do it for your own device and monitor it here: https://heartcortex.ai/monitor. Start from a template, follow the HEART specifications, then register your device with its claim code.
What is inside: the code, how it works, and the specifications it follows · All demo devices
A demonstration that replays a one-hour story. Refreshes every 10 seconds.