LEGO Powered Up Connector

Recently (years, not decades) LEGO introduced a new family of motors, sensors and control system – it was and is a bit confusing, but whether you think of LEGO WeDo, Control+, Powered Up, Spike Prime or the new Mindstorms 51515 it is all based around common backbone and, especially, a common connector – a 6-pole non-stackable plug.

Which, by sheer coincidence naturally, is completely incompatible with the old Power Functions connector from LEGO, who also claimed not to intend to manufacture an adapter cable because reasons.

Before someone jumps at me: I do understand WHY. And no, I don’t mean ‘to sell all motors again’. There is a technical reason not to make an adapter cable. You see, when the Power Functions system was designed, the main source of power was a dumb battery box. Even equipped with a cheaply made switch, a 6AA battery box can withstand all the power draw that stacked multiple motors can realistically take and it is the batteries that will fade before the box melts. With PoweredUp the world is a bit different. The basic box is a remote control receiver, so its outputs are electronically controlled. They have limited output power and for that reason it is necessary to limit the amount of power drains (motors) that can be connected to a channel. So they decided to limit it to one. I’d expect the lights to have a stackable plug though, as the LED lights take minimal power, but that’s a different story.

Okay, so what about that connector, or why am I writing this post?

The PoweredUp family has several very interesting motors with speed and position feedback, but at the same time it can power a simple motor like the old Power Functions M-Motor, with smooth power control even if without actual speed regulation. So it would be great to be able to just replace the PowerFunctions battery box with, say, Powered Up Technic Hub and gain smooth remote control of your existing creations, isn’t it? How about not needing to buy all motors over again? Sounds good? So why don’t we buy a few Powered Up connectors… wait, what, not available?

They are proprietary.

There has been some reverse-engineering going about and the most important findings can be read on the famous Philippe “Philo” Hurbain’s website, specifically here: https://www.philohome.com/wedo2reverse/connect.htm

What’s important for us is:

  1. The Powered Up system does not provide constant 9V output (so goodbye IR receivers and PF servos, you need the 9V supply!)
  2. The brick has direct motor output on pins 1 and 2 – we just need to connect the motor somehow
  3. To enable ‘dumb motor’ mode pin 3 (logic ground) needs to be connected directly to pin 6 and through 2.2kΩ resistor to pin 5 (‘WeDo 2.0 motor’)

Funny enough, even the dumb motors (like the WeDo 2.0 motor) have all 6 wires going to the motor and only there the identification wiring is done. In my case I opted to put all the components within the plug and lead out only the two power wires of the motor.

So I went ahead and designed a 3D-printable connector that is compatible with the Powered-Up sockets.

Rendered CAD design of the connector

The size is exactly that of a LEGO connector, with one limitation: the LEGO connector has a cutout to let a folded cable leave the connector upwards making the depth when plugged exactly 1 stud. Since this connector needs to be soldered (LEGOs is crimped), it needs a tiny bit more space inside, so I opted to provide two exits for the motor cable: straight out or at 90° angle, you choose which way to build it depending on your preference and integration concept.

To make this connector you will need a very well calibrated and accurate 3D printer. The tolerances are tight and if the dimensions are even a bit off you will not be able to get the contact pins in.

Connector straight from the 3D printer

This is how it looks like when printed. There’s a slot on the underside the purpose of which will be clear in a moment.

The electrical contacts are made out of pins pulled from a standard goldpin connector (0.6mm square pins). They are inserted from behind (from above in the picture) and need to be pushed in until they reach their stops. The ground pin does not have a stop, it should reach the front edge of the plug – ground shall make connection before other pins do.

Connector underside

Now the slot is there to put a drop of thin cyanoacrylate glue to secure pins in place. This is not a very strong fix, but will help pins from lifting. Don’t glue them just yet, as soldering will destroy the bond.

Populated plug – 90° cable exit

Now comes the hard part – and I do mean it’s really tricky to get it all soldered up. It’s tight. If you are not very proficient at it, it may be better to clip the back wall of the plug out.

From left to right: Motor A, Motor B, Ground, VCC (unused), ID1 (connected over 2.2kΩ to Ground), ID2 (connected directly to Ground). If you want your motor to act as if it was a train motor, connect ID1 to VCC directly, save the resistor.

Plug sealed with resin

Since the place is so scarce, I opted against some sort of a lid and instead sealed the plug with UV resin. This way there’s protection against shorts within the plug and the whole thing becomes more mechanically stable. And let’s face it: it’s easier to reprint the plug than to disassemble it without melting the plastic in the process.

Splicing it in

Whether you replace a PF connector on a motor or – like I did – cut a chinese clone extension cable in half to make an PUP-PF adapter, you need to use the two middle wires. The outer wires carry 9V constant power, which is not available with PoweredUp control bricks.

Wiring to keep Medium motor to spin the same way like WeDo motor does

If you splice this plug into an PF extension cable, best keep the polarity like in the photo above. This way a PF M-Motor will behave exactly like the WeDo 2.0 motor does (spin direction wise).

Voila. Now your WeDo / Technic / City hub will see your PF motor as a simple WeDo motor and you will be able to control it with your phone app or (City Hub) with a hand-held radio remote.

If you wish to try this yourself, just drop me a message.

This is how both writing options look like when plugged in
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73 Responses to LEGO Powered Up Connector

  1. Ildefonso Zanette says:

    Nice work! You should put the connector’s STL on thingverse.

    • Marek Lewandowski says:

      Thanks, but I don’t want to put it on Thingiverse…
      1/ There’s too much stuff lifted off Thingiverse and used for commercial reasons, I avoid posting there things that I put a lot of effort into making.
      2/ I’m not entirely clear about their terms and conditions of their right to use posted designs.
      3/ I’m not sure if LEGO has some protection on features of this plug. I did not copy their design features, my connector is designed from scratch to mate with their sockets, but still, there may be some geometry that they managed to protect and I don’t want trouble from posting my design files online.

  2. Hi dear, how are you doing? Loved to see this adapter.
    Will you publish it on thingverse?

    KR

    • Marek Lewandowski says:

      Hi, thank you,
      as I mentioned above, right now I don’t want to publish it, especially not on Thingiverse. But if there’s interest I can provide these either printed or share the design in a private channel.

  3. Yair says:

    This is great. We were looking for a way to print the connector. Can you share it with me please?

  4. Andrew Glina says:

    Looks really cool. I’d love a chance to give it a go myself.

  5. richard felder says:

    Hello – great looking plug – I’d like to give this a shot. Sounds like I need to post here to request the file? Thank you!

    • Marek Lewandowski says:

      Actually, should be enough to message me on euro bricks, but if you did i didn’t get a notification :^)
      You got mail

  6. Felix Storm says:

    Hi, I would also be interested in trying out the connector – would you send me the file(s)? Thanks! Felix

    • Felix Storm says:

      Thanks a lot for the design and for sending me the files! I already printed and soldered 2 of them and they work remarkably well. Using PETG even soldering (which I was concerned that it might be a problem due to the heat) worked without any issues. And my sons are very happy about the additional LED lights for their LEGO train and will even be more happy with the two N20 motors to come 😉
      If you see any chance to make the connectors available publicly then people would probably really love them, but I can definitely understand your concerns.

      A few technical notes:
      – I really like your idea to use standard pins for the metal parts!
      – LED lights: Connect ID1 through a 2k2 resistor to GND and leave ID2 unconnected. Power will be on pins 1 and 2 as for motors, but with a different ramp profile (i.e. they start with a lower voltage). Also, power will go up until the full battery voltage, so an appropriate resistor is needed for the LED(s). And even reversing seems to work, so e.g. for a train a red LED in the back and a white one in the front (connected with opposite polarity) should work.
      – For testing I made myself a fully connected cable with jumper pins at the end. I cut out the back of the connector with a knife and then soldered all pins to 6 open wires of a standard jumper/breadboard cable.
      – To seal up the soldering area and to fix the cables, I used UV activated super glue with also seems to work very well and really is dry in a matter of seconds.
      – Just in case anybody is interested in trying it out – there is a project on GitHub to emulate Lego sensors using an Arduino: https://github.com/ahmedjouirou/legopup_arduino

      • Marek Lewandowski says:

        Thank you very much for your feedback! Especially about PETG working too, that’s good news. Interesting observation on the LED thing, I have to try it out!

        Right now the connectors are available semi-publicly. Every single person who cared to write me a comment here, email or in any other way asked for the file – got it. Of them all I got any sort of feedback from all of two… And it really helps to know if a design is printable and usable for others!

  7. Michał says:

    Dzień dobry, jestem również zaineresowany wydrukowaniem takiej wtyczki. Czy podeśle mi Pan pliki. Z góry dziękuję.

  8. ked says:

    Great post. Thank you!
    Can you please share .stl?

  9. Tomasz says:

    May I also get one 🙂 Thank you in advance.

  10. Peter says:

    Great work! Can you please send me the design files?
    Thank you!

  11. Schredd says:

    Hi, nice work. Please send me the STL files. Thanks!

  12. Gennady says:

    Hi, Marek! It’s really cool work! Can you share STL-file with me please?

  13. Arty says:

    Hi, I request an electronic copy of the STL file(s) you designed for the printable PoweredUp connector. My e-mail is [cut for security] Thanks in advance.

  14. Michaël Perdaens says:

    Hi, Marek!
    Great idea, thanks for making this!

    Could you send me the stl file?

  15. Adam Majer says:

    Hi, could you send a STL file. Thanks you.

  16. Sergserg says:

    Hello, I really enjoyed your work! May I have stl files, please? I will try to make this) […email…]

  17. Mohamed chikhaoui says:

    Could you please share the stl file? Thank you in advance.

  18. Robbo says:

    Hi there, fantastic work! Thank you for making this and for being willing to share. I would love to give this a go on my SLA printer, if you’d be willing to share the file.

    Thank you again.

  19. Ryan says:

    Hi.
    Would it be possible to get a copy of this file please.
    And do you have the female end too?
    Thanks.

    • Marek Lewandowski says:

      check mail 😉
      My own end is definitely male only 😀
      a PoweredUp receptacle can be purchased online, so I didn’t care much to design a replacement. The issue is, the female part is the one with spring contacts, so it’s hard to jury-rig reliably.

  20. Aaro says:

    Wonderful diy project to try out. May I have file too?

  21. Benedikt says:

    Hi, I like the project and I want to do it myself. Could I have the stl file?

  22. Ivan Nikitsenka says:

    Hello,
    Could you please send me the STL file

    Great work ! Thank you!

  23. Jean Muls says:

    Nice work! May I have a copy of your .stl file? Grand merci.

  24. Sean says:

    Can I please request a copy of the file.
    Thanks in advance

  25. Hi, Marek nice work.
    very impressive Can I please request a copy of the file.
    Please can you send me the STL files
    Thanks in advance
    Regards from Bob
    Thank YOU

  26. Nikos says:

    Hi Marek,

    Awesome work and write up!

    Would you please share the STL file?
    My MK3S+ will be arriving in a few weeks and I cannot wait to print the PU connectors. What printer do you use for printing them?

    Cheers!
    Nikos

  27. WH says:

    Nice work. Can I please a copy of your project?

  28. FR0DO says:

    Very nice work and description Marek,

    Could you please share the model in a step format for further modification?

    Kind Regards
    Held Frodo

  29. Josef Bednář says:

    Hi Marek,

    Well done! I’m trying to find out some cable extender for my lego power up models and the only one, which I found is too expensive for such
    a piece of cable with two connectors.
    So I decided to print my own connectors and make my own extender. Could you please share your design with me. I will try to draw the female connector, build the extender and if it will be successful, I will then share my female connector with you.

    Many thanks in advance.

    Josef

  30. lee young says:

    very very nice work !

    can you share your stl file?…

    that connector design is too hard for me…

  31. Ryan Dennis says:

    This is great would love to try it out, thanks.

  32. Jason Jacobs says:

    Hello, can I please get the STL? Thanks

  33. Jason Jacobs says:

    Nice job! Can I please get the STL?

  34. TIRESIZEMATTERS says:

    Good work right here!
    I would love to try this STL file please. Have you also designed a female PUP socket as that would solve all my current hurdles:) Thanks!

  35. Aur Vasile says:

    Hi Marek,

    The connector look great and also the idea of using pins available in electronic components. Having a few PF1 elements and this being end of life, I would like to try to make an adapter like yours to drive PF1 motors with the BT Hub.
    Is it possible to share the SLT for the connector?

    Thank you!

  36. Cyrill Oppikofer says:

    Good Idea, I like how you used standard pins. Could you send me the model?

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