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Member since May 2020 • Last active May 2020
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  • in Electronics
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    That's correct, it's a battery pack, for 3 AAA bateries.
    The idea is to eventually power the curcuit from MK connector where I measured I have +9V.
    On the video I'm only making a test taking advantage of the fact that in Unifon I have access to same cables so I don't need to take the stairs ;)

  • in Electronics
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    Successful test :)

    Now off to coding part (controlling this via BLE from mobile device).

    Thank you @Robin and @allObjects :)

  • in Electronics
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    It's taking shape.....

  • in Electronics
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    Thank you @allObjects and @Robin for time you put into this :)

    So indeed, all this time I thought that unlocking action is triggered by grounding MK. Analyzes of @allObjects shows that it should be KE. So I double-checked and you're right :) I was grounding KE and put wrong info in one of the first posts in this thread. To my defense this generator is installed in a place that is hard to get to, so I was relying on small mirror to read the labels.

    In any case, it's definitely KE that is getting grounded.

    I also did a bunch of measurements:

    Is the voltmeter an analog needle type or a digital LCD type? Black ground and Red positive probes?

    It's a digital LCD type, with black and red probes.

    1. The voltage drop on on R18 by measuring between MK and MASA. The voltage drop is 9.6V.
    2. The VAC between X1-1 and X1-2 (the black cables from the coil) and it's 13VAC.
    3. The drop between MU and MASA is 14V.
    4. The drop between KE and MASA is only 0.6V (this is what I need to pull-down to ground).

    Does this information change anything in values of resistor or transistor type I should use ?

    Today I got pulled into work and did not manage to do the shopping. Hopefully tomorrow I will go buy the missing parts :)

    Thank you both for all your awesome help:)

  • in Electronics
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    Hey Robin,

    Thank you for your suggestion on how to test it without endangering MDBT42Q.
    I will try to do some shopping for parts tomorrow and give it a try in the evening.

    Do you have access to a voltmeter?

    I do and I was trying to confirm your deduction of what the voltage drop on R18 is. Unfortunately to no avail. I have a trouble identifying this resistor. Unfortunately the labels are just below of them and are not readable. I was trying to recognize it by the color code, but also there doesn't seem to be any that has brown-gray-brown.

    If you could pull the circuit out I could inspect the connection on the bottom side, however this is out of question - as I'm not sure I would put it back together :)

    Do you have an idea which resistor would it be on the photograph without the wires?

    it between X2-6 ground and X2-1 the 11V supply

    Just to confirm, the X2-1 will be the black slot with label "1" on top - the one on the bottom of the picture to the right of the slots labeled "EZ". I'm I right?

    Thank you Robin :) Have a good night!

  • in Electronics
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    Gush, didn't add attachments. Fixing it.

  • in Electronics
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    Good morning Robin :)

    Ok so it's a little bit hard to make a photo of what I'm shorting in the box, because it's a huge tangle of cables and I can't seem to take a good photo of.

    Instead I used the photo with all cables removed and added schematic of how I think I should connect. Please find it attached. I also marked where the electric lock is connected to (EZ label). However I would prefer not to interact with this part. The cables I want to short imitate human pushing the button on the Unifon to open door. The intercom generator controls the time the lock is unlocked. Even if I short it only for a fraction of second the door is unlocked for like ~5 seconds. That's a behavior I like and I want to keep when I trigger opening from Espruino :)

    Also I'm attaching the photo of the Unifon internals that helped me figure out what I should be shorting. It's much clearer. On that photo I was shorting inputs labels 10 and 9. This is what allowed me to figure out the colors of cables that I should be shorting downstairs.

    What is your mains voltage in your country?

    I'm in Poland and the AC standards is 230 V / 50 Hz. Despite my googling effort I can't find what the standard for DC are. I begin to think there is no standard and engineers just make it up as they go:)

  • in Electronics
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    Hi Robin,

    One of my favorite learning videos is the exploding LED, around 03:08

    You should check out ElectroBoom youtube channel. It's run by Iranian electric technician living in Canada, who is constantly getting shocked or have stuff catch fire. I find it very entertaining :)

    Any chance you could provide images of the exposed intercom wiring and how the shorting of pins is done?

    I was trying to make the best photo of the wiring I could get, but really it's quite messy, so not easy to make something out.

    So I googled around for this intercom model and actually internet came through:) I'm attaching:

    1. Photo of this board with all cable removed.
    2. Schematics of correct connections.
    3. The schematics of the generator.
      4.The photo of the actual wiring. It's cluttered and messy.

    Unlocking action is triggered by shorting the black and brown cables.
    On picture without wires these are labelled MASA (this is polish for ground, black cable) and MK (brown cable).

    I figured this part out by inspecting how unifon in my home is wired. Also I shorted these two clips with a cable and it opens the lock. I measured there is 0.6V between these wires.

    Thank you again for helping me with this :)

  • in Electronics
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    Thank you Robin.

    I'm in CEST (GMT+2) so I'm calling it a night for tonight.
    I will continue tomorrow, or more likely on Monday, since it seems I need to find a brick&mortar shop that sells transistors.

    I really appreciate you help.