duifkelego

9v and PU hybrid

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Posted (edited)

I had some free time to work on another idea.

I modded a PU system and some 9v wheel holders to power the PU unit off the 9v tracks.

A first proto , still got a long way before it's a reliable and easy to assemble solution.

see results below and the video on bricksafe

DSC_0130.JPG

https://www.bricksafe.com/files/duifkelego/9v and PU hybrid.mov

Edited by duifkelego

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Please, can you explain us the advantage of your system beside unlimited power supply? Keep in mind that LEGO abandoned the 9V system 10 years ago and rails become less available  and increasingly expensive with the time. Ok, if you have them ...

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@duifkelego please fix the extension of that link, I could see in a HEX editor that it was some movie file (QuickTime I think) and rename it so my movie player accepted it...

You'd better upload it to youtube and embed it.

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Posted (edited)
1 hour ago, Giottist said:

Please, can you explain us the advantage of your system beside unlimited power supply? Keep in mind that LEGO abandoned the 9V system 10 years ago and rails become less available  and increasingly expensive with the time. Ok, if you have them ...

I really don't like batteries for several reasons ( another discussion , don't want to preach)  Another advantage would be less spacy PU hubs which are easier to incorparate in engine designs.

I want to combine this with the 2 motors on 1 hub thing I did a while ago. Maybe I can run that experiment tomorow and see if the PU hub can run 2 motors with unlimited amp supply for longer periodes . I already know it can run 2 motors untill the batteries die ( in half an hour running :P  and dependent on the weight of the entire train...) For that I'm looking into boosting the PU hub PWM signal so I can draw 2 or 3 amps from it and run even more motors on it.

I'm also experimenting with track made from O-gauge rails for my own layout for circumventing the expensive original rails. these 2 would combine nicely in my head.

But there is still the thingie of having to push the button on the train to connect the hub and the remote , any ideas on that ?

29 minutes ago, JopieK said:

@duifkelego please fix the extension of that link, I could see in a HEX editor that it was some movie file (QuickTime I think) and rename it so my movie player accepted it...

You'd better upload it to youtube and embed it.

I added the .mov extension to the file name , is it working now ?

Edited by duifkelego

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Well now your link is not working anymore, but downloading it requires about 50 Mb not very friendly to others of course :)

B.t.w. on your idea: it would be advisable to add a Gold Cap capacitor. If your train would bump the microcontroller of the PU unit still gets juice :)

(Oops sorry about that something went wrong with your (double)post).

Works great now! At least on Safari :)

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On 5/11/2019 at 8:59 PM, Roadmonkeytj said:

Would love to see more detailed pictures of your pick ups

I too would be interested in detailed pictures! Did you make the wheels yourself?

Unfinished_Projects

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So I took it a step further today and built the setup into my extended 60197.

60197%20extended.jpg

The 2 motors on 1 channel project from this previous post was also called into service. 

To get a more detailed picture of what was happening to the electronics I also built in a voltage and current meter. This is connected to the power pickups directly before the power goes into the hub.

meter2.jpg

so the PU hub is drawing 0.05 amps from 8.8V when on but idle. When I set the motors to full power , the voltage went down to 7.1 to 7.6 volts and current went up to 0.7 amps. The voltage swing is mainly dependent on the train going through a curve.,

the voltage drop from 8.8V when idle to 7.6 is because there is some resistance in the electrical loop. This is probably somewhere in the pickups and willbe my next point of attention.

I've uploaded some more movie to my bricksafe but beware they are somewhat large files. Will be looking into a youtube channel for this.... I need some education on this video posting stuff.

 

22 hours ago, Unfinished_Projects said:

I too would be interested in detailed pictures! Did you make the wheels yourself?

Unfinished_Projects

Some wheels were cast in silver with the mold taken directly from the plastic wheels.  My girlfriend is a juwel smith so this was the fastest way :)

Some other wheels were printed in steel by shapeways from the 3d model I made. I want to develop a little further before i'm comfortable sharing more detailed pics as the wheels are not rolling as freely as I would like them to. Though I am flattered by the request. 

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7 hours ago, duifkelego said:

Some wheels were cast in silver with the mold taken directly from the plastic wheels.  My girlfriend is a juwel smith so this was the fastest way :)

This is a neat idea.  I have heard of plenty of people trying to machine wheels from stock, but you are the first I can recall doing it from a casting.  Do you worry about it tarnishing and losing conductivity?

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Actually I am worried about that. The ultimate goal is to have them machined or cast in alpaca / new silver. that's the material companies like Peco use for model rails and tarnishes very little.

I'm also building track with peco rail profiles so having the wheels in the same material as the rails will also minimise contact resistance between the 2. but I have to find the perfect wheel before I can draw a mold again. The exact size of the axle hole is giving some issues

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11 hours ago, duifkelego said:

Actually I am worried about that. The ultimate goal is to have them machined or cast in alpaca / new silver. that's the material companies like Peco use for model rails and tarnishes very little.

I'm also building track with peco rail profiles so having the wheels in the same material as the rails will also minimise contact resistance between the 2. but I have to find the perfect wheel before I can draw a mold again. The exact size of the axle hole is giving some issues

If running peco rails you will want to build a rail scrubber car ... Theres plenty of designs in scale railroad groups of just about any size (save for z maybe).  They are good looking rails but do need cleaned regularly

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Well, the conductivity issue as well as any voltage drops etc. become much less of a headache, when you use some sort of "buffer" between pickup and Hub. Capacitors will certainly do.

However, TLG provides us with an almost perfect - but expensive - solution: The rechargeable battery pack 8878 - now phased out. But: They are still available all over the net. The 8878 accepts any DC input voltage from 9  … 18 V. It delivers on its output solid 7.2 V.

Four of my 9V trains use a modified 9V train motor as pickup, feed that into 8878, that on powers a 2I/O Hub, which drives the 9V train motor. Let me know, if this is of interest to you. This would also work very well with your custom pickups.

Best wishes,
Thorsten  

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I've built many locomotives with super capacitor banks that can power the locomotive for about 45 seconds, recharge in about 10 seconds. Allows me to use non-power plastic track sections here and there as long as there is enough powered track sections to keep the caps topped up. 

27638739469_70ee877bf0_b.jpg

Edited by legoman666

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On 5/16/2019 at 9:36 AM, legoman666 said:

I've built many locomotives with super capacitor banks that can power the locomotive for about 45 seconds, recharge in about 10 seconds. Allows me to use non-power plastic track sections here and there as long as there is enough powered track sections to keep the caps topped up. 

27638739469_70ee877bf0_b.jpg

Do you have a link to more info on this? I know we talked about it in person but ive forgotten some of what you told me lol

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