OctoPrint-JamSentry

This plugin provides support for JamSentry, a DIY sensor for detecting filament jam and runout conditions. No printer hardware or firmware changes are required to use the sensor. Original information on how the concept behind JamSentry came about can be found at: https://robogardens.com/?p=2220

Updated build information and instructions can be found in the wiki. STL files and the Arduino sketch can be found on the Printables website at the following URL: https://www.printables.com/model/223589

JamSentry is a compact device consisting of a microprocessor (ESP8266), a filament movement sensor, and a magnetometer. The magnetometer attaches to the side of the extruder motor and detects when the motor is driving. Basically, if the motor is driving and the filament isn't moving, then you have a jam or have run out of filament. On detection of this condition the JamSentry can:

1. Raise (or lower) a line to provide a hardware indication emulating a filament runout switch
2. Send a message to the G-Code sender (OctoPrint) alerting it to the situation (this plugin implements the receiver)
3. Send an alert of the condition (IFTTT is used)

The JamSentry is a WiFi device and is configured via a web interface.

Setup

Install via the bundled Plugin Manager or manually using this URL:

https://github.com/hotbutteredhtml/OctoPrint-JamSentry/archive/master.zip

Nothing special is required to install the plugin, but for it to work you need to setup the configuration parameters below.

Configuration

The JamSentry detects filament jams and runouts. When detected an alert is sent to the OctoPrint server on a given port. A password is also sent along to ensure that it is a legitimate JamSentry alert. To receive the alert properly, the following must be setup in the OctoPrint JamSentry plugin settings:

1. The address of the JamSentry (typically http://192.168.1.xxx). If the printer has multiple JamSentry units (one per extruder), then only one will be displayed. However the JamSentry plugin will still receive alerts from all units. The status can be displayed on a separate webpage.
2. The port to listen on. This defaults to 27100. You can change the default that JamSentry uses. The JamSentry plugin must be configured to listen on whatever port the JamSentry uses to send the alert.
3. Password. Since a jam detection will likely pause the print, you want to make sure it isn't a prankster. A password can be set in the JamSentry. If so, OctoPrint must have the same password set so that it can authenticate the message. The default password is "JamSentryPSWD".
4. Custom G-Code to send when a jam or filament runout is detected.
5. Whether or not to pause when a jam or filament runout is detected. If used, then G-Code for pause and resume should be set up in the G-Code Scripts in the OctoPrint settings. Note that pause should be avoided in OctoPrint versions 1.3.7 and 1.3.8 as it does not work reliably. If you don't supply any G-Code script for the pause and resume functions, then the printer will pause, but in place. So the hotend will gradually melt a little blob in place.

NOTE: Example Pause G-Code script:

; relative XYZE
G91
M83

; retract filament, move Z slightly upwards
G1 Z+5 E-5 F4500 

; absolute XYZE
M82
G90

; move to a safe rest position, adjust as necessary
G1 X0 Y0          

Example Resume G-Code script:

; relative extruder
M83

; prime nozzle
G1 E-5 F4500
G1 E5 F4500
G1 E5 F4500

; absolute E
M82

; absolute XYZ
G90

; reset E
G92 E{{ pause_position.e }}

; move back to pause position XYZ
G1 X{{ pause_position.x }} Y{{ pause_position.y }} Z{{ pause_position.z }} F4500

; reset to feed rate before pause
G1 {{ pause_position.f }}