capacitive sensor - does it get affected by magnets
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Hi
I have been having issues with the duet ir sensor, giving inconsistent readings. So I have switched to use a PINDA 2 probe.
My heated bed is a replica of the Prusa magnetic bed and it has magnets in the middle of the bed as well as along all four sides. So it's not possible to avoid them.
I think the magnets are affecting the sensor.
For example the lower left corner has three magnets and my print wouldn't stick. However everywhere else, isn't ideal but at least sticks to the bed. Also it reports the largest difference in height along the top edge of the bed which is where the magnets are.Curiously it doesn't seem to be affected in the middle of the bed but there are several magnets there.
I was wondering would a capacitive sensor be any better? Or a bltouch?
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The problem with all the capacitive sensors I have tested is they are very slow to respond. And slow is not what you want.
I have one printer with a BLTouch and it does not seem to be affected by the magnets in the bed.
I have another with a Inductive sensor and it is affected by the the magnets in the bed as you can see here.
I deal with this by cheating. I edit the height map file and locate those readings that are obviously quite different from the surrounding 8 readings and change them to "blend in" better with the surrounding readings. Is it perfect? No but it works.
I have one printer that uses a magnetic sheet that covers the whole bed. It does not seem to affect the Inductive sensor. Or if it does the affect is uniform over the whole bed.
In both cases I am happy using the Inductive sensor.
The BLTouch is good but the clicking can get annoying when you are creating a height map 21 x 21 setting ther BLTouch to acquire 2 consecutive readings. Nearly 900 clicks is truly annoying.
If you try an Inductive sensor get one with a high switching frequency - at least 1000Hz - but you can get them up to 7000Hz.
Frederick
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I think I will gve the bltouch a try. My logic is, it's the only onethat actually contacts the bed. Inductive and capacitive don't actually touch the bed.
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@ageis said in capacitive sensor - does it get affected by magnets:
I think I will gve the bltouch a try. My logic is, it's the only onethat actually contacts the bed. Inductive and capacitive don't actually touch the bed.
Which is a good thing to my way of thinking. They are much faster than the BLTouch since they are no parts that need to move.
Frederick
