There’s no negative here, unless you’re calling ground (-). It’s referenced on the silkscreen as gnd, so that’s what I’m referring to it as.
I’m thinking this is your basic triggering circuit, where the NO switch may require a series resistance, not sure right now
The +24 remains disconnected, it’s not required. The 3V3 pullup is internally provided by the toolhead.
I have all the stuff to test this, I’ll do so in a bit and update. Will post a video of the result if it works. Requires a lot of crimping of a new JST2.0 connector, so give me like an hour lmfao
I’m confused by your use of NPN and PNP - they both can be used here equivalently.
Only difference is if the base sources or sinks the signaling current, which is outside of the scope of the 3v3 signal line interface. Purely up to the circuit design external to that, and you could choose to implement it either way.
NPN would trigger with a pullup base resistor, PNP would pull down with a base resistor.
However none of those are required if you’re using a mechanical switch, which I think you indicated above? Don’t use a transistor at all, and just hook the switch up directly to the signal line.
it mattered to me what we were running through the contact, voltage or ground, and typical PNP sensors will provide voltage and NPN sensors will provide ground
you can always do some extra tinkering to convert it one way or the other, but i was not sure if we needed to apply voltage to the pin or ground to the pin is basically what it boiled down to.
If i tie ground into a limit switch on my product, it wont register the input. it will only register if i tie + into the limit switch.
I have not done it to the snapmaker toolhead, no. I was trying to figure out what should be used for it at work we manufacture security products and the controllers work opposite.
I did some googling and I see that NPN and PNP are industry terms - sorry I haven’t come across that, I thought you were referring to raw transistors. I see there are typical applications for sensors, and that this inductive sensor likely conforms to those 2 common uses, moreso the NPN.
I believe its quite typical for there to be a very minimal current draw on any of these prox sensors (or photo electric sensors or ultrasonic sensors), it doesnt require much for the controller to see theres a diference as long as its the correct type of output
Something with a variable output rather then ON or OFF would need something larger to scale against
In the past, I made this microswitch holder that you could move around under the nozzle and have it hit it. Not ideal, but was a stepping stone. This pic is after I broke the switch off lol.
Then later I would just cover the plate with foil and do this. God bless deltas and their ability to move so friggin fast. https://photos.app.goo.gl/9uWvxJrFKYMbKmfRA. I think this was taken in slow motion, video may or may not work properly.
Usually could probe a 10x10 grid in under 2 minutes.
Anyways, that was over 4 years ago.
This was how fast it usually ran: https://photos.app.goo.gl/Qi5kh4wuH2CoNjrN8. It’s running the 7 point delta calibration pattern without taking measurements just as a test.
I just mention these as ways of getting probing on glass that appear to be compatible with the snapmaker - all you have to do is close a circuit to trigger the probe, see below:
So with this Snapmaker, it appears the probe input signal circuit is pulled up with a 47Kohm resistor from the 3.3V source, drawing only 0.071mA through a short to ground. The probe also draws 0.071mA in normal operation when triggered, so I’m quite confident there is no pulldown resistor provided in the factory inductive probe.
To trigger the sensor you can just put a normal open switch between the IO line and ground. Here I have exactly that and am triggering a G30 probe manually.
When the switch closes the machine detects that as a trigger (which pulls the voltage on the pin to ground).
Pretty simple, crimped up a new JST2.0 connector, and the switch goes from Green (IO) to Black (Ground). It leaves the picture to take a current measurement, it was always 0mA untriggered, 71mA triggered.
If I was going to use a limit switch I would use the semi-automatic allen key personally, from that fifix thread. I think that speaks to me the most. Also would give new life to my drawer of allen keys LOL
Less so me than him, but thanks for the compliment anyhow hehe
That is a lot of you have going on your bed there, very cool to see so much on there at once, looks like that glass does wonders for the flatness as expected.
@MooseJuice
Yes its crazy, very less problems since i use this stupid little piece of a window.
@Streupfeffer
Think it played around with the things about an hour, told cura not to keep parts away from eatch other and did it manually. But more was not possible
I have tried, but it can not put things together as i did, I printed things in things when there was enough space in it. tomorrow i post a photo of the hole print. But now good night I will go to sleep.
at work we manufacture security products and the controllers work opposite.
