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Remote Control for 4.5V. Would it Work?

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Just a thought I had,over the weekend I have got 5 X old blue motors from my mothers attic and after de-fluffing and cleaning have got them running albeit a bit squeaky. hen they have been sat in a box for the last 25 y or so doing nothing and were 20 years old or there about prior to going into the box.

I had an idea whilst thinking about rebuilding some of those very old trains. Is there any reason why a power functions IR unit would not work with them? OK, I know the connections totally different but I figured that would be easy to fix by cutting a PF extension cable in half and adding some 4.5V connectors to the naked wires.

I understand that 4.5V is only half of the PF 9V so I guess that they maybe slower, but figured that the seed control probably worked by varying the amount of power the motor gets anyway.

So has anyone tried this, does it work or is this idea way to simplistic and there is something else the PF IR unit needs that a 4.5V battery box just won't provide?

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You could do that, but convert the voltage to a max of 4.5V. Alternative: use an Arduino with motor shield. Very easy if you put the whole system at 5V. IR receiver + Arduino is very easy (my high school students also manage to do that).

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I understand that 4.5V is only half of the PF 9V so I guess that they maybe slower

Nope, it works the other way around. If you give a 4.5V motor a 9V supply it'll go double the speed. For a short period, until it burns out anyway...

but figured that the seed control probably worked by varying the amount of power the motor gets anyway

The amount of power yes but that is done by giving it the full 9V in shorter or longer pulses. Still wouldn't keep your 4.5V motor happy for long.

So has anyone tried this, does it work or is this idea way to simplistic and there is something else the PF IR unit needs that a 4.5V battery box just won't provide?

I'm not sure what the voltage is that the circuits in the IR receiver need. 4.5V might not be enough. It's safe to try anyway; you won't kill the 9V IR unit by giving it only 4.5V.

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I'm not sure what the voltage is that the circuits in the IR receiver need. 4.5V might not be enough. It's safe to try anyway; you won't kill the 9V IR unit by giving it only 4.5V.

There was a thread around here when PF was still fresh. The IR receiver runs happily with a range of voltages, incl. 4.5V.

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Of course since the logic in it is 5V or it might even be 3.3V. It should be even more efficient than with 9V (although the LiPo is 7.something volts).

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So before I attempt this and mess it up, can I ask (Not being an electrician.) I see that the PF cables have three wires, but obviously the old 4.5V system only has two. So which of the PF wires do I use, is there some kind of wiring diagram that is easy for people with limited understanding of such things to use? Do I have to connect the third wire to anything?

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They actually have four wires:

diagram.gif

Link: http://www.philohome.com/pf/pf.htm

Inner cables are for the turnouts, out cables for powering (so power from the battery goes through the outer cables, the motor cables are the inner two).

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They actually have four wires:

OK, I did not know that.

So if I am to run the two wires from the 4.5V battery box, which ones should I connect them up to when they get to the IR receiver? I assume the two marked as 9V. (Only it will be 4.5V in this case.) Then the two wires coming from the 4.5V motor will need to go to the 'Out' section of the IR receiver. I assume from your comment the ones annotated C1,2 and with the dotted line? Do these wires actually correspond to the layout of the wires on the cables, for example the two outside are the 9V and the two inners are the C1,2 or is that just wishful thinking?

Or is it just way to complicated and not worth the bother for someone who does not know what they are doing? Pity as it seemed like quite a good upgrade to the old 4.5V trains and would make them more compatible.

Edited by TheBrickster
Quote of entire post removed.

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Do these wires actually correspond to the layout of the wires on the cables, for example the two outside are the 9V and the two inners are the C1,2 or is that just wishful thinking?

Did you look at that link at all? If you had you would have found this picture:

pfcon.jpg

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Did you look at that link at all? If you had you would have found this picture:

Yes I did look at the link, however I imagine that in order to wire it up to an old fashioned 4.5V battery box and motor I would actually have to cut the wires?

The old blue motors and battery boxes use a very different plug system for connection.

I was thinking of using a PF extension cable (As it is relatively cheap.) so that it has the PF connectors at one end which will be able to connect to the IR Receiver using the proper connection bricks as in your diagram, but then the cut ends of the wires would have to go into the little plugs that fit the older style of motor / battery box.

So my question about the layout of the wires is not one of how they are at the PF connection brick end as I assume those would be right, but more one of how they are aligned in the actual length of wire. If I cut it, will the two outer wires be the 9V-0V and the middle two be the C1-C2 or is that not how it works?

Also, if I were to do this what would I do with the four ends not connected to anything, would this matter, should I just tape them off (To isolate them?) or do I need to do something else entirely with them?

I guess I could just try it, but I do not want to risk breaking the IR receiver. Like I said I am not electrically minded or trained, so this may seem a very simplistic idea to those of you in the know, but it seemed like a good idea to me. However it does seem that maybe it is much more complicated than I at first thought.

Edited by TheBrickster
Quote of entire post removed.

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OK, still none the wiser. I have tried to use a PF IR unti with an old 9v Battery Box as this only has two wires. Even though it works the PF motors fine without the IR unit in the middle, as soon as I add the IR unit nothing works even though I connected it with the official PF extension cable?

Anyway, after looking over the wiring diagrams again and getting a little confused i thought I would draw a picture of what I mean as I am not sure I got my message across. I have uploaded this to my flickr gallery in the hope that someone will be able to tell me which if either of my solutions will work? Or if not then how to go about this, but please in non electrical jargon terms.

Thanks.

Link to flickr; My link

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A 9v pp3 battery / cable will power a rf receiver: connect only the two outer cables (c0 and c1 are not connected). This can be an easy custom cable.

After the ir receiver connect pf motors: the receiver generates the correct control signals.

It may be that the c0 and c1 lines are also powered via the extension cable - I never checked.

If there is insufficient power for the ir receiver it might work, but not be able to generate the outputs onto c0 and c1

The power on those control lines are Pwm modulated and control the actual speeds of the motors

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There are people that have already made it. See at

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=426979

the only thing that change is the power supply that you can achieve by means of a non-lego battery box with four rechargeable batteries (i.e 4,8 V)

or an old battery box http://www.bricklink.com/catalogItem.asp?P=bb45c02 with which you can use the old 9v normal wire.

play well (leg godt)

Sergio Monai

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One more question then. On the old 4.5V battery box/motor, I am guessing that it does not matter which plugs you use for + or - V as all that happens if you change them is that the motor runs in the opposite direction.

I think that link on Bricklink pretty much says what I want to know otherwise, it is just that he has used an old 9V rather than 4.5V. I don't want to damage the cable on the IR unit so I will use an extension cable and cut that (As they are a lot cheaper.) and I have plenty of room in the tender on my engine to hide the wires.

Anyway, I did finish the engine last night so now am building the tender so I need to sort this out over the weekend if I am going to do it. It is a bit like James the Red Engine if anyone is wondering. Whilst not actually copied exactly I have my book open at turn of the century (1800-1900C) 4-4-0 passenger engines for inspiration. Will post pictures when done.

Thanks.

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One more question then. On the old 4.5V battery box/motor, I am guessing that it does not matter which plugs you use for + or - V as all that happens if you change them is that the motor runs in the opposite direction.

Since the IR receiver takes its power from the inputs as well as powering the motors it probably does matter which way you connect the 4.5V battery box. It should be pretty easy to follow from the top (positive) end of the batteries through the switch though, so you should be able to work it out. I'm not sure reverse polarity would be good for the IR receiver electronics. The positive end of the batteries should go to the 9V lead on the IR receiver.

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Ok thanks everyone for your help with this project, there were times when I felt like giving up. But tonight I have taken the PF IR unit by the horns and connected it up as per the diagram on Bricklink provided by yourselves.

The IR unit is neatly tucked away in the tender based around a black 4.5V battery box and I just have the power cable running to the motor from there. I am using an old black 4.5 V battery box and most of the cabling is hidden under the coal and water tank,

I have set it running it but not yet on track and it seams go pretty well, although I expect it may need rubber 'o' rings on two of the main drivers for grip when pulling stuff. I am using a 1976 black type III 4.5V motor with tecnic axle holders to run two of large western train wheels as divers on the 4-4-0 engine.

Over all I am rather pleased with the result and look of the train. I have a few tinkering greebles to add to the tender then i will get some photographs up.

So thanks again for your help.

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That's great! Nice to hear that it all works. Looking forward to your pictures now.

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That's great! Nice to hear that it all works. Looking forward to your pictures now.

Here is the thread with the photographs. I put it in a new one simply as it seemed more appropriate what with it being about the MOC itself rather than an electrical problem. But I guess they are related at least.

Thread about 4-4-0 steam train.

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I know this is old thread but I found out today that the 9v black connector will power the 4.5v without any conversion, and as the PF extension lead has both the PF connector and the old 9V connectors on them you can connect up the old 4.5V train engine to the power function IR receiver and battery box without any conversion. I don't think the increase voltage will bother the motor much it's still pretty low, I will be using it with my motor, but don't quote me on this do it at your own risk. Weren't the 4.5V motor reused in the 9V train anyway?

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Pretty sure you can't use the 9v cables on the 4.5v motors without modding. The connectors are entirely different.

There is a 9v Freestyle motor that looks very similar to the old 4.5v train motors, maybe that is what you are thinking of?

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18 hours ago, yakacm said:

I know this is old thread but I found out today that the 9v black connector will power the 4.5v without any conversion, and as the PF extension lead has both the PF connector and the old 9V connectors on them you can connect up the old 4.5V train engine to the power function IR receiver and battery box without any conversion. I don't think the increase voltage will bother the motor much it's still pretty low, I will be using it with my motor, but don't quote me on this do it at your own risk. Weren't the 4.5V motor reused in the 9V train anyway?

I'm afraid you have many things mixed up here...

4.5V train motors and old 12V train motors look the same, but we're talking before 1980. New 12V train motors looked different but still used the same connectors:

765c190.jpg?1

9V train motors have the same shape as the second generation 12V train motors but use the 2x2 plate connectors. IR train motors look the same and use the same connector. PF train motors are still the same shape but have a cable attached.

The PF extension lead will connect to 9V and IR train motors, but not 4.5V or 12V.

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Nope I have nothing mixed up, I am not talking hypothetical here I am talking about something I have in front of me working, if you don't want to believe me that's up to you my friend but I am not going to start and argument about it. I made my comment, not to ask if this would work but to tell anyone who was interested that it works, do with that piece of information what you will, end of.

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It will be easiest to show a photo so others can see what you have done to avoid cross talking.

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I know exactly what he means, it will work. I don't have pictures of the two together, but the underside of the left connector here:

https://shop.lego.com/en-GB/LEGO-Power-Functions-Extension-Wire-8886

Will connect directly to the studs on this motor here:

https://img.bricklink.com/ItemImage/PL/bb07pb01.png

Without any modification.

 

Edited by Heppeng

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