Problem with IR sensor

  • Hi
    I have connected the IR Sensor to the Z-probe connector next to the Panel Due….When powering with USB only the sensor flashes 4 times, as expected. But after that it always reads 220 independent of distance
    I checked the connectivity of the signal with an ohm meter and it shows that it is connected.....
    Since it blinked 4 times it is powered correctly. So I powered the Duet Wifi with 24V and now it always reads 0
    Can I do some more troubleshooting?

  • O and I have this config.c… it came from the reprap config
    ; Z-Probe
    M574 Z1 S2 ; Set endstops controlled by probe
    M558 P1 H5 F120 T6000 ; Set Z probe type to unmodulated and the dive height + speeds
    G31 P500 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
    M557 X15:285 Y15:285 S20 ; Define mesh grid

  • administrators

    Most likely you have connected the OUT pin of the sensor to the wrong pin on the Z probe connector (it should go to the IN pin), or there is a bad crimp connection in that wire.

  • I suspected that yes…since when I measure volt on out and gnd I measure 0.09V and the value drops to 37
    I did recrimp the out and it is connected to the in on the duet...........
    And I did measure ohm between the underside of the sensor to the underside of the connector on the duet and it is 0 ohm....

  • administrators

    I guess it's possible that the OUT pin of your sensor isn't properly soldered to the PCB, although it must have passed testing.

  • O and it triggers when I get close to the sensor(red led) so yes it must be something with the out signal. See photos for connections
    had to solder to the sensor, since I don't have enough space for the connector

  • solved….R4 on the sensor was badly soldered....soldered both sides and seems to give sensible data 0 when far from bed but always 985 when values in between. Duet detects it as z-stop.
    Shouldn't the values vary?

  • administrators

    I am glad you solved it. However, both R4 and R5 would have to be open circuit to give the original symptom. So please check R5 too.

  • Well , the LED worked so R5 is fine. Only out didn't work. But I checked and resoldered R5 and R4 under a microscope and it looks fine now…..C1 is supposed to be not mounted I suppose

  • administrators

    R5 doesn't affect the LED, it's R6 that does. R5 is the resistor next to L1. C1 is not mounted.

  • A indeed sorry… I'll check r5 too

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