Desvejk Posted July 26, 2021 On the basis of a post I ordered the parts from AliExpress to make a Powered Up Extension Cable. I would like some advice. The photo shows my best efforts. When I plug in the light sensor - it lights up ( but I did not test beyond this) The train motor does not run. Without a crimping tool and rather basic soldering iron I was able to make a cable. I have tried to test the voltage and all seems OK, but I must admit I don’t really know what values I should be getting. I would also seek some advice on how to test the voltage values of the pins. I’ve used computer ribbon cable, is this OK? The extension cable that I made is about 100cm, it this too long? The size of the male plug from AliExpress had to be trimmed and reduced in size to fit into the LEGO HUB. I’m absolutely stumped. Any advice would be gratefully received. Share this post Link to post Share on other sites
JaBaCaDaBra Posted July 26, 2021 59 minutes ago, Desvejk said: I would also seek some advice on how to test the voltage values of the pins. Use a DMM to test the cable for continuity, any cheap meter will do. 1 hour ago, Desvejk said: computer ribbon cable, is this OK? Perfect, if it is previously used cable test for continuity 1 hour ago, Desvejk said: The extension cable that I made is about 100cm, it this too long? No problem at all, this is quite low frequency digital signal plus power Where did you get the female plug? Share this post Link to post Share on other sites
Desvejk Posted July 26, 2021 (edited) 1 hour ago, JaBaCaDaBra said: Use a DMM to test the cable for continuity, any cheap meter will do. Perfect, if it is previously used cable test for continuity No problem at all, this is quite low frequency digital signal plus power Where did you get the female plug? Thanks for your reply. I’ll try a continuity test. The female plug came from an AliExpress seller. the lot was listed as 10Pcs/lot Programming Series Robots Model Building Blocks Education Steam Connector Cabe Parts For WEDO 2.0 Motors Sensor Toys Thanks Des Edited July 26, 2021 by Desvejk Share this post Link to post Share on other sites
dr_spock Posted July 26, 2021 Also check that you didn't shorted any pins together with the solder since they are pretty close together. The train motor is ID'ed to PU hub by resistance (lack of). Check your 100cm of wire doesn't have a high resistance to throw off the detection. Share this post Link to post Share on other sites
Toastie Posted July 26, 2021 And then there is this "mirroring" thing ... (never) "learned" that the hard way with RS232 cables - and I am not talking about null-modem or whatever cables; just 1:1 extension cables. Is pin "1" (or whatever it is called) on the PUp plug wired to the corresponding pin "1" on the PUp socket so that this matches with pin "1" on another PUp plug? The plug pins are a mirror image of the socket pins - when looking onto the solder side. Yeah, sure, I know. You may be well aware of this (of course), it is just that >I< repeatedly screwed up on this. Sigh. Best Thorsten Share this post Link to post Share on other sites
Desvejk Posted July 27, 2021 (edited) 3 hours ago, Toastie said: And then there is this "mirroring" thing ... (never) "learned" that the hard way with RS232 cables - and I am not talking about null-modem or whatever cables; just 1:1 extension cables. Is pin "1" (or whatever it is called) on the PUp plug wired to the corresponding pin "1" on the PUp socket so that this matches with pin "1" on another PUp plug? The plug pins are a mirror image of the socket pins - when looking onto the solder side. Yeah, sure, I know. You may be well aware of this (of course), it is just that >I< repeatedly screwed up on this. Sigh. Best Thorsten Hello Thorsten Thanks for good advice. I’ve certainly done this before. 11 hours ago, dr_spock said: Also check that you didn't shorted any pins together with the solder since they are pretty close together. The train motor is ID'ed to PU hub by resistance (lack of). Check your 100cm of wire doesn't have a high resistance to throw off the detection. Thank you dr_spock, that’s another thing to check. Edited July 27, 2021 by Desvejk Quoting error Share this post Link to post Share on other sites
Desvejk Posted July 27, 2021 Thanks to those who have replied to this topic. After quite a few hours working with the resources and skill I have, I have found this task too difficult. My pinouts and continuity testing seems fine. When I plug a train motor into the hub using the extension cable the motor does not operate. I conclude that the connections are the problem, but I’m unsure of a solution. It’s a pity, especially given that LEGO does not sell an extension cable and the third party product is not cost effective for me to purchase from Europe. Has anyone else had success with producing a PoweredUp extension cable? Share this post Link to post Share on other sites
dr_spock Posted July 27, 2021 I had sucess making my own PU to PF adapter cables. One thing I ran into making my own connectors was the male and female plastic parts would fit but the electrical contacts weren't touching. They were off by a teensy bit. I had to modify my CAD design and/or re-bend some metal so there is electrical contact. Ah, good old RS232 cables. I had to make a null modem cable recently and couldn't remember which pins go where. My mind was null. Share this post Link to post Share on other sites
Toastie Posted July 27, 2021 2 hours ago, Desvejk said: Has anyone else had success with producing a PoweredUp extension cable? Never tried, just clipped off the plugs and used them elsewhere. However, no reason to give up here! And your skills are certainly up to the task, I am sure. So more questions to find the solution(s)! Do you have a multi-meter at hand, as @JaBaCaDaBra suggested using for testing? Do you have dumb PUp lights (LEDs) at hand? With regard to the light sensor: Do you get any reasonable readings from the sensor when using your extension cable (i.e. comparable readings from the hub with and without)? 1 hour ago, dr_spock said: Ah, good old RS232 cables. I had to make a null modem cable recently and couldn't remember which pins go where. My mind was null Heehee, welcome to the club! I made a custom RS232 cable to connect my XZ Spectrum to my laptop via RS232. In addition to the usual pin mess even with "standardized" DTE to DCE RS232 cables (or better: "who is who" cables, and yes, there are reasons to occasionally revert to that technology ), Sinclair defined their own pin names; they found it more intuitive to call RX TX and TX RX. Same with RTS and CTS. Best Thorsten Share this post Link to post Share on other sites
JaBaCaDaBra Posted July 28, 2021 15 hours ago, Toastie said: RS232 Regular solder of 2 on 3 and 3 on 2 I had a DEC PDP 11/25 once with VT100 terminals Share this post Link to post Share on other sites
Desvejk Posted July 28, 2021 Thanks dr_spock, my thinking is that pin alignment is very critical when using the hub and control functions. Share this post Link to post Share on other sites
Desvejk Posted July 28, 2021 Hello Thorsten I've tried connecting the light sensor to the extension cable that I made. While the sensor brick lights up there is no control when using the PoweredUP app or the controller. My conclusion is that the pins are not aligning. You can see the images here https://www.icloud.com/sharedalbum/#B0aG1CvrSGiZdCz Cheers Des Share this post Link to post Share on other sites
M_slug357 Posted July 28, 2021 @Desvejk What about dupont style connectors...? I was thinking that for extension& alteration purposes, these might be easier than trying to reverse engineer/3D print bits that match Lego's official hardware...? My basic thought process was (sans illustration) this: PuP batt box --> PuP male connector--> ((desired cable length)) --> female Dupont connector 1x6 --> male Dupont connector 1x6 --> ((desired cable length)) --> PuP lights/motors/etc Does this make sense? Share this post Link to post Share on other sites
Desvejk Posted July 29, 2021 11 hours ago, M_slug357 said: @Desvejk What about dupont style connectors...? I was thinking that for extension& alteration purposes, these might be easier than trying to reverse engineer/3D print bits that match Lego's official hardware...? My basic thought process was (sans illustration) this: PuP batt box --> PuP male connector--> ((desired cable length)) --> female Dupont connector 1x6 --> male Dupont connector 1x6 --> ((desired cable length)) --> PuP lights/motors/etc Does this make sense? M_slug357, I understand your suggestion and I do have Dupont connectors. You could be on to something here. My original thought was not to cut the LEGO cables. I'll give it some thought and maybe I can come up with a hybrid solution. The male parts from AliExpress seem to work with the pin alignment. Cheers Des Share this post Link to post Share on other sites
Toastie Posted July 29, 2021 2 hours ago, Desvejk said: I understand your suggestion and I do have Dupont connectors. Des, then I'd really go for that suggestion of @M_slug357! @dr_spock is also using this approach since long, as far as I recall. There were several posts here on EB where he demonstrated that; both for PUp and for PF. I myself have cut at least 10 PUp "cables" to use that approach. As I wasn't aware of the Ali Express stuff at that time (it was early stage PUp time, and as soon as the hubs were becoming cheap on BL, I wanted to connect 9V train motors to these hubs), I purchased a couple of the cheapest PUp device (the lights = LEDs), cut the wires and fitted then via Dupont connectors to the 9V motors. Works beautifully well. So I don't see any reason why that would not work with: (any) motor (cut wire and fit with Dupont male connector) -> Dupont female connector - cable - Dupont male connector -> Dupont female connector soldered onto PUp plug. Lots of soldering though. This way, you can also experiment with different lengths of the extension cable (blue above) or - when not required - connect the motor directly with the modified PUp plug wire. Also, when you use that direction (female side exposed when unconnected) the power source (hub) is not exposing its contacts - otherwise accidentally shortening them is always a "threat" When you take that route, you may want to consider using heat shrink tube to securely isolate the soldering pins of the Dupont connectors. A bit of work, but can only recommend. Worked/works flawlessly for me. Best Thorsten Share this post Link to post Share on other sites
Desvejk Posted July 29, 2021 4 hours ago, Toastie said: A bit of work, but can only recommend. Worked/works flawlessly for me. Best Thorsten Thank you Thorsten I may give this a try when I can buy some PU cables. The light accessory is difficult to buy from Lego Australia with stock supply hard to predict. This may change soon (hopefully). Cheers Des Share this post Link to post Share on other sites
dr_spock Posted July 29, 2021 Dupont connectors are quite handy for mixing and matching and testing stuff. I think I paid less than $20 CAD for a dupont crimper a couple years ago. Share this post Link to post Share on other sites
Toastie Posted July 29, 2021 Oh crap I simply could not figure out what "Dupont connectors" really are ... I thought any 2.55 mm pitch connectors are just that. So I was talking about the soldering effort ... but it appears as if Dupont connectors are crimped onto the wire, correct, @dr_spock? Is this reference a good one? https://www.instructables.com/Fitting-Dupont-Connectors/ Well, I stand correct then: I am using these: https://www.reichelt.de/de/en/precision-sockets-2-54-mm-1-x-13-straight-mpe-115-1-013-p187277.html?GROUPID=7435&START=0&OFFSET=16&SID=93864a34b28fc8084dd88cc0deedf68bff49fe84015d4da016504&LANGUAGE=EN&&r=1 Reason: Very small footprint. Downside: Needs soldering. Best Thorsten Share this post Link to post Share on other sites
