Filament Runout Sensor for EZR Struder Ender 3

Filament Runout Sensor for EZR Struder Ender 3

OVERVIEW:

This filament runout sensor + bracket is designed for an Ender 3 (Pro) with direct drive EZR Struder, used with TPU or any other filament. The sensor costs less than $5 from AliExpress, including a cable. (Note: I bought two sensors (with cables) so I could cut and solder the two cables together to make a long cable.) https://www.aliexpress.com/item/33028816768.html?spm=a2g0o.productlist.0.0.6fcc744bNX9yD3&algo_pvid=9438d87f-1666-454f-b92e-f0eefa71a679&algo_expid=9438d87f-1666-454f-b92e-f0eefa71a679-1&btsid=0b0a555f16109894313648923e845d&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

REQUIREMENTS:

Some soldering may be required to lengthen or shorten the cable to fit your printer. Also, some soldering is required to modify the switch inside the runout sensor.
The firmware must be modified. It is recommended that you save a copy of each firmware version in case you need to revert to a previous version of the firmware.

SWITCH MODIFICATION:

Pry open the sensor housing as follows. Insert needle nose pliers into the long slot on the end of the sensor, and pull the pliers handles apart to separate the halves of the housing. On the circuit board, the three pins at the bottom of the switch are COM (Common), NO (Normally Open), and NC (Normally Closed). Cut the middle (NO) pin close to the switch body. Bend the NO pin away from the switch body. Solder a jumper wire from the NO pin to the NC pin. https://photos.app.goo.gl/5FJjWY1ThLaMc5T46

PRINT BRACKET:

Print the bracket. I used PETG, 20% infill and support. PLA should work fine.

CONNECT WIRES TO THE PRINTER CIRCUIT BOARD

The cable has three wires for: CTRL, GND, +5V. The +5V wire powers the LED in the sensor. The CTRL and GND wires sense when the filament sensor switch is CLOSED (no filament present) and OPEN (filament present). This video will help you decide which pin to use for the CTRL wire. https://www.youtube.com/watch?v=UL_DzCfwSjg&ab_channel=DorkyTim

FIRMWARE UPDATE

This video goes over the basics of modifying firmware. https://www.youtube.com/watch?v=GQlAN88ebNM&ab_channel=FusionSource-3DPrinting
This also helps with modifying firmware for a filament runout sensor. https://www.youtube.com/watch?v=5Jt-Qc67FDo&ab_channel=Crosslink
This is a good one. https://www.youtube.com/watch?v=6023oBYmXW4&ab_channel=Crosslink

BRACKET DURING PRINT

Here is a short video. https://photos.app.goo.gl/mH81YrJ4YQAgx8tk8