BLV MGN Cube IR Sensor

The IR sensor is a really nice little toy, it is small, do not make any sound and is pretty cool ( at least to my eyes). If you got the full kit from Sealand, you have a small IR sensor.

Apparently a lot of people have some problem to set it up. To be honest, the change from the Firmware 2.x to 3.x made my life a bit difficult but I manage to find a way using the configurator. I end up with the following settings in my config.g

; Z-Probe
M558 P1 C"zprobe.in" H5 F120 T6000                 ; set Z probe type to unmodulated and the dive height + speeds
G31 P25 X-2 Y-16.4 Z10.4                        ; set Z probe trigger value, offset and trigger height
M557 X15:285 Y15:285 P5                            ; define mesh grid

Now this is where it gets interesting. The configurator is setting the detection limit to P25. In this excellent tutorial it shows that the value P500 should be use. If you leave the value P25, it will detect the bed from a really far away distance. It is really safe for a first run, but the accuracy is really poor. The P500 will detect the bed around 3mm away with a really good accuracy.

My kit was delivered with the 3mm heated bed and a metal plate covered with PEI. Unfortunately for me I got a plate with both side structured. I definitely prefer the smooth plates so I ordered a new one and waiting impatiently it arrives. However, on the structured plate I did not have any problem with detection, I only have a problem with collision !

The nozzle ( in fact the all hotend ) is just too long ! The sensor is mounted correctly on the printed part but the nozzle is 3.5 mm below the sensor. It should be normally around 1.5 to 2mm max below, to allow to have an offset. In my case, the nozzle is just crashing on the heated bed.

At first I through I had some problems with the sensor detection and I just check by putting the plate per hand under the sensor and it was working. After a few test, I realize that the hot end is too long.

So If you have a full BLV Cube from Sealand, check that you hot end is not too long. For the moment I am running manually the Z calibration. I may redesign the holder to get the extra 2 mm needed or I just simply glue the sensor with loctite !

I hope it will help you ! Leave a comment to tell me how you are doing with your sensor !

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