When preparing for a print job I re-levelled the bed and all seemed OK, then the sun came out and the next auto-home was low, so I shielded the printer and the next home was nearer. I then turned the lights off in the printer and the home level changed again but almost recovered when the lights were turned on again. The differences were not very big but around 0.1mm in the worst case, so will have a real effect on the first layer performance. It seems that any source of light is going to have some small effect on the sensor so I am going to try shielding the sensor with tape and try a strip of tape on the bed in the home area to see if the effect is repeatable. I'll update later. I was wondering if anyone has fitted the inductive sensor yet and has any results. I know that @Alex9779 has one to fit but I may have missed the reports.
@mike01hu i am running the inductive for a while now... and you didn't miss a report, I didn't write one yet...
No I think I switched to the side of the other major 3D print gurus, keeping my knowledge, findings and solutions secret... Getting the most out of open source...
Heh don't you dare I'm still annoyed I have a great toolbox solution for the space around the BB but I can't use it effectively because "someone" won't release the blooming source files, so I can't reconfigure it to fit my tools. Going to be easier to start again rather than trying to hack at the STL's, which is a shame as it's a nice design.
That doesn't sound right at all. The sensor is carefully designed so that it is unaffected by ambient light right up to the point at which the phototransistor saturates. Bring sunlight can saturate the sensor if it reflects off the glass directly into the phototransistor, but ordinary room lighting doesn't affect it. There are some notes about bed surface in the generic usage instructions at https://miscsolutions.wordpress.com/mini-height-sensor-board/.
I'm using the red PEI coated aluminium bed but there was no doubt about the effect of the light. The error is small and I live with it by checking the Z offset required after a home.
My IR sensor behaved erratically too (glass bed). I removed and reattached it lots of times and finally it stays mostly consistent. I suspect the reason may be the mounting bracket, If I screw it tight it will slightly misalign and not be parallel to the bed anymore. After looking more closely to the bracket I saw small groves from the two screws which reinforced the misalignment. I always wanted to make a better IC mount with either enough space for washers or one which is not adjustable to avoid this source of error altogether.
