PrintSheriff
An Obico alternative for free local spaghetti detection
Researching Obico or The Spaghetti Detective for 3D print failure detection? If your priority is a webcam-based detector that runs on your existing OctoPrint host, PrintSheriff is an option to evaluate. Its machine learning inference runs locally, without a subscription or cloud prediction server.
This guide describes PrintSheriff, not a feature-by-feature review of Obico. PrintSheriff is an independent project and is not affiliated with or endorsed by Obico.
What free local inference means
The open-source OctoPrint plugin runs a MobileNet image classifier through TensorFlow Lite on your Raspberry Pi or x86 printer host. It scores webcam frames for visible spaghetti failures and checks a sliding window of recent scores before raising an alert. You do not need a separate inference computer, GPU, account, or subscription.
No inference-hour quota
The plugin runs on your own hardware, so detection does not stop when a metered allowance runs out.
Offline detection after setup
Install the plugin, runtime, and model first; after that the detector runs without a network connection.
No camera uploads by default
Optional image sharing for model improvement stays off unless you enable it.
Optional phone alerts
Configure ntfy to receive failure notifications; those need connectivity to your ntfy server.
Initial model downloads and updates connect to your configured model server. If you enable notifications with image attachments, those images are sent to your configured ntfy server. Local inference does not mean every optional feature is offline.
What you need for local 3D print failure detection
- An OctoPrint installation on a supported Raspberry Pi or x86 host with a compatible TensorFlow Lite runtime.
- A webcam aimed at the print and build plate, with the print centred in the image.
- The PrintSheriff plugin and downloaded model.
- Timelapse capture, or the plugin’s optional real-time capture mode, to provide frames during printing.
Start with the OctoPrint plugin setup and camera placement guide, then follow the installation and notification videos. Check the ML pipeline and Raspberry Pi inference measurements to understand the hardware trade-offs.
Is PrintSheriff the right alternative for you?
Consider it if you want free OctoPrint spaghetti detection, local processing, and optional ntfy alerts. Do not assume it replaces every feature of another monitoring platform: this page does not promise feature parity, migration tooling, or compatibility with an existing Obico installation. Review your remote-access, printer-management, and notification needs separately.
Know what the detector cannot guarantee
PrintSheriff targets visible spaghetti, not every kind of 3D printing defect. False positives and missed failures are possible. The model only sees a centre-square crop of the webcam frame, so camera placement and lighting matter. It is a monitoring aid, not a safety system or a substitute for safe printer operation.
Try spaghetti detection before installing
Use the online 3D print failure detection demo to score one of your print images. The demo uploads your image to the server and follows the storage policy shown there; it is separate from the local plugin. Developers who prefer hosted inference can use the 3D print failure detection API, with its own RapidAPI plans rather than the plugin’s unlimited local inference.
Run it on your own printer.
Free local detection for OctoPrint — no account, no subscription.