Connecting an inductive sensor to the Anet A8
I bought an Anet A8 over christmas. When I bought my printer from Gearbest, I also bought the inductive sensor that they sell.
It doesn't seem to work, and I think it might be broken. However, I have no idea how I can test if it is broken. This is what the wiring looks like and how it's connected to the board
I'm not sure if I need to modify the wiring in order to hook it up to the A8's motherboard. I have no idea what the pinout is on the A8's mobo, and it's not indicated either. Most guides deal with using RAMPS when it comes to installing such a sensor. I'd like to know how to connect this to my board, if possible.
The printer works fine otherwise, so I don't think the board is broken or anything. For now I've resumed using the normal endstop, but I would like to enable bed levelling by installing this sensor. (or a different one if necessary)
How do I get this working?
@SeanHoulihane I've managed to connect it using instructions I've found on Youtube after looking up stuff related to Tom's answer. I went for the voltage divider option.
Tom van der Zanden Correct answer6 years ago
I am not entirely familiar with the ANET A8 electronics, but it's very unlikely it's any different from how any other mainboard works, so any instructions that work for RAMPS should work for your board as well.
The sensor you linked to has an operating voltage range of "6V to 36V". However, the endstop connectors (on any mainboard I've come across) only provide 5V - not enough for the sensor to work. You could verify that this is also the case for your ANET board with a multimeter.
(Assuming the colour coding is standard) you'll need to connect the black wire to GND, the red wire to 12V, and the yellow wire through a diode to the signal pin of the endstop connector. The anode of the diode should connect to the signal pin and the cathode to the wire coming from the sensor.
The diode is required, because otherwise the 12V signal from the sensor will damage your electronics, which can only accept 5V. Any ordinary diode will do (for instance 1N4148). You should enable endstop pullups in your firmware when using this method (though if your board already has physical pullups this is not necessary but won't hurt either).
Note that if the sensor is inductive, it will also need an appropriate (metal) surface to trigger off. Unfortunately, it is not clear from the product description what type of sensor you have bought, and (amusingly) gearbest doesn't know either:
Hello, is this Sensor capazitiv or induktiv? Thank you verry much.
It is an auto leveling sensor for 3D printers
I believe its a non-standard mainboard from a firmware point of view, and people seem to be changing the firmware when they use this inductive sensor. I know when I switched to an opto sensor, I needed to invert the signal to the mainboard.
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Content dated before 7/24/2021 11:53 AM
Sean Houlihane 6 years ago
Those connections don't fill me with confidence, the wiring colours are unusual. Hard to tell unless you can track down the actual sensor datasheet (the vendor has likely just put this together speculatively from off the shelf parts)