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Offline DaleSchultz  
#101 Posted : 03 June 2019 21:30:31(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
that could be a good explanation.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline kiwiAlan  
#102 Posted : 04 June 2019 00:02:47(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,460
Location: ENGLAND, Didcot
Originally Posted by: Minok Go to Quoted Post

As the capacitor buffer is feeding input to the voltage regulator, is it the case that as the capacitor discharges to a certain point, the voltage regulator no longer can provide its requested output and shuts off the load effectively, thus not further discharging the capacitor, so when the power comes on again, the capacitor still has a some charge in it and thus needs much less current to top its charge off?


That would be my suspicion as well. I think if you measure the voltage across the capacitor at the point where it drops from 9mA to 0mA you will find the capacitor voltage is equal to the LED voltage at normal (or possibly slightly reduced) brightness. So once the LEDs stop conducting the capacitor is loosing minimal charge.

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Offline DaleSchultz  
#103 Posted : 04 June 2019 21:37:20(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
so, now I am turning my attention to very small plugs.

Ideally I want something that will allow them to be daisy chained so that the next coach, pickup, and flicker module can be plugged together as needed.
as small and flat as possible.

Something like this:

plug.png

I am thinking it is best to run wires along the underside of each coach and run the wires to almost the middle of the next coach. Essentially creating a bus for teh power along the underside of the train. Anti-flicker modules and LED lights are then added as needed.

tiono has suggested the search "mini steckerset 2 polig" on Ebay but I looked on ebay.com and ebay.de and did not find them.
The Roco 40345 is an actual coupler and not what I am looking for either. Many of my old tin plate coaches do not even have NEM pockets.

Even the small JST plugs do not seem to daisy chain, so I may have to go for a 6 pole socket into which I insert 3 plugs, and connect the positive and negatives of teh 6 pole socket together....

or small solder pads on a small board.... perhaps with room for the pickup shoe diode....




Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#104 Posted : 04 June 2019 22:12:12(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
I may need to make them out of header pins - like this:

https://tonystrains.com/...73-2-pin-micro-connector
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline dominator  
#105 Posted : 04 June 2019 23:10:25(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
How do you hope to allow for flexibility, especially with those tin plate carriages because they swing a long way sideways when changing direction. [ mind you, I do run M track ].
I also have a lot of analogue locos, and would like to be able to run something like this on either digital or analogue. One of my 280 trannys puts out 29 volt AC in the reversing pulse, and when converted through a bridge rectifier, steps up to nearly 50 volts. I presume then it would be better to have a master coach set up for digital and another set up for analogue.

Dereck
Northland. NZ REMEMBER 0228 for ä
Offline DaleSchultz  
#106 Posted : 04 June 2019 23:10:28(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Since I expect these installations to be pretty permanent, perhaps soldering onto a small board would actually be the simplest:

Imagine a tiny circuit single sided board like this:

board.png
(R1 and D1 to be positioned vertically next to C1)

This board can be used as follows:

1. Populated with C1, R1 and D1 as anti-flicker module, rightmost three pairs of solder pads cut off, supply wires soldered to remaining pair.

2. Populated with C1, R1 and D1 as anti-flicker module, rightmost two pairs of solder pads cut off, LED module soldered to one pair and supply wires soldered to remaining pair.

3. Unpopulated onnector board glued to underside of coach, allowing wires to be soldered on to pads from adjacent coach, previous coach, flicker module, LED module

4. Connector board glued to underside of coach, pickup shoe soldered to C1 positive, and D1 in place. Next coach, anti-flicker, and LED modules connected to solder pads.

In other words, a single multi-purpose board that can be cut down as needed. It would be very flexible in use. If there is lots of space, as in a baggage car, use one to handle the flicker and a nexus for all the connections. If space is limited, use just for the flicker module in the bathroom, and run wires from it and the LEDs to the underside to connect with each other, and power, etc.

I think such a board could be made for about 33c each if I order 100 from https://jlcpcb.com

(PCB thickness 0.6, matt black, one sided, lead OK)

Thoughts?
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#107 Posted : 04 June 2019 23:16:50(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Originally Posted by: dominator Go to Quoted Post
How do you hope to allow for flexibility, especially with those tin plate carriages because they swing a long way sideways when changing direction.

I think that small multi-strand wires will be flexible enough and can be made to look like brake hoses running past the couplers.

Originally Posted by: dominator Go to Quoted Post
I also have a lot of analogue locos, and would like to be able to run something like this on either digital or analogue. One of my 280 trannys puts out 29 volt AC in the reversing pulse, and when converted through a bridge rectifier, steps up to nearly 50 volts. I presume then it would be better to have a master coach set up for digital and another set up for analogue.

Dereck

yes, that reverse pulse would probably destroy the little regulator, so for analog use a bigger regulator or some other voltage limiting device would be needed in addition to the diode. If that can be done then all the rest can stay the same, but the lights will go out when the train slows down and the voltage drops below about 10 V

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline kiwiAlan  
#108 Posted : 04 June 2019 23:21:55(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,460
Location: ENGLAND, Didcot
Originally Posted by: DaleSchultz Go to Quoted Post

Even the small JST plugs do not seem to daisy chain, so I may have to go for a 6 pole socket into which I insert 3 plugs, and connect the positive and negatives of teh 6 pole socket together....

or small solder pads on a small board.... perhaps with room for the pickup shoe diode....


The only connectors I have come across that will stack the way you seem to be suggesting are the ones used for piggyback PCBs like Arduino/Raspberry Pi/etc shields where multiple PCBs can be stacked. But these connectors will be far too large for what you want.

Offline DaleSchultz  
#109 Posted : 04 June 2019 23:24:54(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
yes, that I what I meant by header pins. Since then, I am now thinking that a small connector board that can have wires soldered onto small pads will in fact be easier.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#110 Posted : 04 June 2019 23:37:09(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
an additional idea:

If I make the end of the board the same with as the regulator, I could place the solder pads so that the two boards can be soldered together. That would allow the regulator to be on the underside too, making brightness adjustments very easy, and providing increase flexibility in the placement of the LED strip in the roof.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline tiono  
#111 Posted : 05 June 2019 04:00:27(UTC)
tiono

United States   
Joined: 09/02/2010(UTC)
Posts: 224
Originally Posted by: DaleSchultz Go to Quoted Post

tiono has suggested the search "mini steckerset 2 polig" on Ebay but I looked on ebay.com and ebay.de and did not find them.


https://www.ebay.de/itm/Mini-Steckerset-2-polig-connector-set-grid-Steckverbinder-2pin-pcb-Stiftleiste/372665688683?hash=item56c49b226b:m:mh_Y0M4HL2m8tcd7cMvsCOg

The problem with pin-connector is; must put something to tighten (maybe adhesive tape?), otherwise the connector will loose after sometime due to coach movement.

Originally Posted by: DaleSchultz Go to Quoted Post

That would allow the regulator to be on the underside too, making brightness adjustments very easy, and providing increase flexibility in the placement of the LED strip in the roof.


I presume you want to put the regulator underside, at the middle of the coach. If your coach is 33cm (full length 1:87 scale), then the regulator may hit turn-out lantern and causing derailment.

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Offline dominator  
#112 Posted : 05 June 2019 04:34:10(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
https://www.ebay.com/itm...:mnUyeGcHk-gMPDk4JWVyz7A

These wont come apart easily. In fact, you might have to relieve the tags that lock these together.
Dereck
Northland. NZ REMEMBER 0228 for ä
Offline tiono  
#113 Posted : 05 June 2019 05:07:49(UTC)
tiono

United States   
Joined: 09/02/2010(UTC)
Posts: 224
Originally Posted by: dominator Go to Quoted Post
https://www.ebay.com/itm/Sale-Mini-Micro-JST-XH-2-5-2-Pin-Connector-plug-with-Wires-Cables-10-100Pcs-New/162642641779?hash=item25de41c373:m:mnUyeGcHk-gMPDk4JWVyz7A

These wont come apart easily. In fact, you might have to relieve the tags that lock these together.
Dereck


But it is probably too big; 2.5mm pitch, total width around 7mm. As compared to micro pin connector, which is just around 2mm width and 1mm pitch.
I am looking for 2 pin 1mm pitch connector
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Offline dominator  
#114 Posted : 05 June 2019 08:41:45(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
I just measured the maximum offset of two 24mm tin plate coaches in the middle of an "S" on 5100 m track. It is 23mm. In that case how long do the flexible leads need to be between the coaches? The distance apart of the coaches is virtually the same. This question is related to joining a series of coaches together electrically with at least two wires between all coaches. I have an idea of how to overcome the problem but would like to see others answers before stating mine.
Dereck.
Northland. NZ REMEMBER 0228 for ä
Offline mario54i  
#115 Posted : 05 June 2019 09:50:36(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Originally Posted by: dominator Go to Quoted Post
https://www.ebay.com/itm/Sale-Mini-Micro-JST-XH-2-5-2-Pin-Connector-plug-with-Wires-Cables-10-100Pcs-New/162642641779?hash=item25de41c373:m:mnUyeGcHk-gMPDk4JWVyz7A

These wont come apart easily. In fact, you might have to relieve the tags that lock these together.
Dereck


I have connectors like these, but smaller, 1.25 mm pitch, bought from Amazon
JST 1.25 mm connectors

They are small but wire is a bit too stiff for our application. The ones from Ledbaron are more flexible.

Regards

Offline DaleSchultz  
#116 Posted : 05 June 2019 15:18:59(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
my normal approach will be to place the regulator in the roof. But if there is enough place on the underside without it fouling things, then it could go on the underside too.
The size of the JST connectors and having to add our own wires that are flexible enough is what is making me think of going to permanent connections. That of course makes maintaining the rake of coaches more difficult for sure, but also not insolvable.

I have installed Eagle software for drawing a circuit board and am learning how to use it in order to draw a proper circuit board.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#117 Posted : 06 June 2019 19:21:31(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
I measured the inrush and stable current draw at various input voltages.

The lines on this graph shows the inrush in blue and stable draw in mA.
The two circles represent the inrush and stable draw when using the digital track current (going through a single diode, so about 17.3V half wave)

drawgraph.png

On the workbench I cannot see the light output changing until I get below 4mA where it drops off rapidly. That is not to say that two coaches running at different levels wont look different from across the room though. I suspect they will look different.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
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Offline DaleSchultz  
#118 Posted : 06 June 2019 19:24:46(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
and here is my current state of my attempt to draw a circuit board in Eagle.

Eagleboard.png

I will be away for a week so I wont be able to do much on this for a while...
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
thanks 1 user liked this useful post by DaleSchultz
Offline Minok  
#119 Posted : 06 June 2019 19:58:17(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 2,019
Location: Washington, Pacific Northwest
Nice. It would be interesting to add a line to the graph with its own axis that depicts for the various voltages how many milliseconds of light is produced when you pull the carriage from the power supply.

That would allow you to dial in the voltage on the performance that actually maters most: bridging a power drop out on a moving carriage.
Toys of tin and wood rule!
---
My Layout Thread on marklin-users.net: InterCity 1-3-4
My YouTube Channel: https://www.youtube.com/user/Minok1217/
Offline DaleSchultz  
#120 Posted : 06 June 2019 20:20:44(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
indeed, but how would I measure that? And how long are the power drops on my layout? And how often...?

Certainly the coach with 470uF capacitor and 430 Ohm resistor seems solid on my layout so far.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline mario54i  
#121 Posted : 06 June 2019 22:16:26(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Originally Posted by: DaleSchultz Go to Quoted Post
and here is my current state of my attempt to draw a circuit board in Eagle.

Eagleboard.png

I will be away for a week so I wont be able to do much on this for a while...


Good start

after a while you will get something like this



regards

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Offline DaleSchultz  
#122 Posted : 06 June 2019 23:36:03(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
well, the idea is one that is very cheap and also very efficient.
Having surface mount components manufactured on the board cheap? I know it would allow us to get rid of the resistors on the typical LED strips, but not much else that I can see.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline dominator  
#123 Posted : 07 June 2019 00:00:49(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
While waiting for various new bits to arrive, I have been playing around with the physical side. Mainly with the 24 mm coaches. The connectors I mentioned above are not too big, and if the leads are placed in the bogies above the axles, and feed along one side of the couplings, then the movement is not too great, especially when the wires feed up through the floor, are bent towards the end of the coach. The wires are not so obvious either. I used a pair of 5 wire couplings which i had, to do the experiment. I haven't looked at coaches with the close couplers yet as i think that would be a bit different.

Some time ago I worked out how to fit LED's into an analogue loco using micro a bridge rectifier and micro CCR.[ they were so tiny you could get 15-20 of them onto your little finger nail and nearly needed a microscope to read the polarity]. It worked, with the exception of a reversing switch for the lights. I have to fiddle around using a mechanical mechanism working off the reverse switch and that is not an easily reproduced in the tiny space available on that 3080 Loco.

The other thing I have been pondering, is if two pickup shoes were used on the master carriage, would that reduce the flicker effect.

Dereck
Northland. NZ REMEMBER 0228 for ä
Offline Minok  
#124 Posted : 07 June 2019 00:47:07(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 2,019
Location: Washington, Pacific Northwest
Originally Posted by: DaleSchultz Go to Quoted Post
indeed, but how would I measure that? And how long are the power drops on my layout? And how often...?

Certainly the coach with 470uF capacitor and 430 Ohm resistor seems solid on my layout so far.


To capture that data would indeed be arduous and require building a test rig if you wanted to be precise and get a large amount of data.

A photo sensor reading then brightness of the led lighting is captured via a analog-digital capture card. Then you also have a timing circuit (well a computer clock) and a relay that is computer controlled ( many methods from serial to usb/arduino et al). You also need the voltage to be computer controlled . Then you write software to test: set the voltage, let the cap fullly charge, cut power (record time) and record brightness of led with time stamps. Presumably you can see in the data when the brightness gets below a threshold of your choosing. For each of the voltage levels (manually set it programmatically set) you can then capture a “time till it’s not bright enough anymore “.
Toys of tin and wood rule!
---
My Layout Thread on marklin-users.net: InterCity 1-3-4
My YouTube Channel: https://www.youtube.com/user/Minok1217/
Offline DaleSchultz  
#125 Posted : 07 June 2019 00:49:01(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
well yes, perhaps I should have added the word "practically" :-)

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
thanks 1 user liked this useful post by DaleSchultz
Offline DaleSchultz  
#126 Posted : 07 June 2019 00:51:17(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
multiple pickup shoes would work yes, but if you are running a train across boosters then this would short circuit the boosters.

can you take some pics of your wiring? I have not yet done that part.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
thanks 1 user liked this useful post by DaleSchultz
Offline dominator  
#127 Posted : 08 June 2019 06:20:15(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
Hope you mean these.
DSC01641.JPG
DSC01642.JPG
DSC01643.JPG

I haven't worked out how to fasten the wires to the bogies yet but I don't think that will be difficult.
I did have a look at some of the later close coupled, 8 wheeler couches but think I will leave them alone at this stage. I couldn't get the body off the frame without putting too much force on the middle area so left them alone. I'll stick with the older metal ones for now.

DSC01646.JPG
DSC01644.JPG
My design for securing pickup shoes to the bogies. Solid fixing and reliable.
DSC01645.JPG

Dereck
Northland. NZ REMEMBER 0228 for ä
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Offline DaleSchultz  
#128 Posted : 08 June 2019 19:23:43(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Thanks for the pics.
I am hoping to use smaller wires, and I only need two.
Can the plug be seen from the side when on track?

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline dominator  
#129 Posted : 09 June 2019 00:35:34(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
If the connector is secured between the wheels it wont be seen. Also, those wires don't stand out unless you get really close [The carriages are quite close together.] so I would suggest running both wires on the same side. Just make sure you leave enough for when they are "stretched " to their utmost. I would even allow a little movement in the wires in the next bogie and after they come through the hole in the carriage, bend them towards the end of the carriage and allow them to be free. Those wires aren't too big, and if you are concerned about flexibility, you will see that there is not a lot of movement when set up properly.. If you buy the same ones I am getting, they come with the wires attached. Save unnecessary work. I used those 4 wires as an example as I didn't have a 2 wire set. Making a couple of little brackets to hold the wires in each bogie might be tricky Dereck
Northland. NZ REMEMBER 0228 for ä
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Offline DaleSchultz  
#130 Posted : 07 July 2019 20:40:34(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
quick update:

I had an electronics friend visit for the weekend and I showed him the project. I had to start with explaining what DCC power is like and what the requirements were, but we soon got to testing my circuit and as simpler one.

The main takeaway, so far, is that the DC-DC converter is using about 15mA.
The strip of 12 LEDs arranged in 4 sets of triplets is using 1mA at 7.5 V

The DC-DC converter does a very good job at maintaining the brightness of the LEDs during short power losses as it maintains the 7.5V output very well, (but is its using 93% of the power).

We did come up with a circuit with almost no significant inrush current, (without the DC-DC converter), but the LEDs dim noticeably during power interruptions, so out next step is to look for a small modern voltage regulator that supplies 7.5 to 8V at very low output currents (< 10mA). This would allow a bunch of coaches to be powered with a single pickup shoe, and one anti-flicker module.

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline tiono  
#131 Posted : 08 July 2019 03:56:32(UTC)
tiono

United States   
Joined: 09/02/2010(UTC)
Posts: 224
Originally Posted by: DaleSchultz Go to Quoted Post

The main takeaway, so far, is that the DC-DC converter is using about 15mA.
The strip of 12 LEDs arranged in 4 sets of triplets is using 1mA at 7.5 V



Are you using MP2307 chip ?
The datasheet said; maximum idle current is 1.5mA (not 15mA) without load. Probably your measurement was incorrect.

If your LED consume only 1mA at 7.5V, may be a linear current regulator will be a better option.
Example of 1mA current regulator diode is: 1N5299UR or 1N5298UR
This is a small CCR (the same size as 1A diode), max voltage is 100V, max dissipation is 0.5W

Assuming the voltage after rectifier is 18V, the LED need 7.5V, then the CCR will drop 10.5V and dissipating 0.01W
Total power consumption, including the LED, will be = 18 * 0.001 = 0.0018 watt
Of course this is assuming your measurement is correct that the LED consume only 1mA.

Offline DaleSchultz  
#132 Posted : 08 July 2019 15:42:44(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Originally Posted by: tiono Go to Quoted Post

Are you using MP2307 chip ?

yes
Originally Posted by: tiono Go to Quoted Post


The datasheet said; maximum idle current is 1.5mA (not 15mA) without load.


We measured it under load, and the circuit drew 16mA. Then we measured the same length LED strip with the same voltage and it drew 1mA, so we concluded that the MP2307 was drawing 15mA

Originally Posted by: tiono Go to Quoted Post
Probably your measurement was incorrect.


I will do some more measurements, when my replacement multimeter fuse arrives tomorrow. (I forgot I had it in Ammeter mode and tried to read a voltage, which blew the 440mA 1KV fuse!)

Originally Posted by: tiono Go to Quoted Post


If your LED consume only 1mA at 7.5V, may be a linear current regulator will be a better option.
Example of 1mA current regulator diode is: 1N5299UR or 1N5298UR
This is a small CCR (the same size as 1A diode), max voltage is 100V, max dissipation is 0.5W

Assuming the voltage after rectifier is 18V, the LED need 7.5V, then the CCR will drop 10.5V and dissipating 0.01W
Total power consumption, including the LED, will be = 18 * 0.001 = 0.0018 watt
Of course this is assuming your measurement is correct that the LED consume only 1mA.



I will double check, yes, the digital current after full bridge rectifier is 17.5 V, so we only need to drop 10 Volts.
I will look at those components - very much appreciated!

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#133 Posted : 08 July 2019 19:37:30(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
just measured the current of the 12 LED strip at 7.5 V: 0.5mA

I will measure it again with the DC-DC converter again soon.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline 5HorizonsRR  
#134 Posted : 08 July 2019 20:54:04(UTC)
5HorizonsRR

United States   
Joined: 05/12/2004(UTC)
Posts: 2,837
Location: NY, NY
Hi Dale! I've been slammed with work the past few months, so I am just discovering this thread. A few notes:

- I went pretty far down this road and my problems tended to vary. I gave up at the connectors (for no good reason). The Micro JST ones are actually still pretty big. Those ones on german ebay are NICE, but a bit pricier.

- If you have some boards done, I'd likely sign up for 100+ if it helps the order! I'd love a solution like this at a cost less than the commercial outfits charge.. Then just run a pickup shoe, the led strings, and car-to-car connections myself...
FS + SBB Era 2-5 and Vintage Marklin
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Offline DaleSchultz  
#135 Posted : 08 July 2019 21:02:31(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Hi John, yes, if I can make solder pads it will greatly simplify making permanent connections. It does mean however, that one needs a method of servicing say, 5 or 6 coaches at a time, I am thinking of a section of track that can be lifted out and carried to the workbench, and rolled over (on foam) to get at the underside.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#136 Posted : 08 July 2019 21:16:23(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
Originally Posted by: tiono Go to Quoted Post

If your LED consume only 1mA at 7.5V, may be a linear current regulator will be a better option.
Example of 1mA current regulator diode is: 1N5299UR or 1N5298UR
This is a small CCR (the same size as 1A diode), max voltage is 100V, max dissipation is 0.5W


These things look rather expensive!

The low price of the DC-DC converter, coupled with its ability to maintain output voltage as the input voltage drops off makes the 15mA it may use not look so bad. Since it can handle a fairly large amount of current too, it may be practical to place it, and the capacitors, in a baggage car, and just run two wires along the train to power the LED strips.

Baggage cars provide lots of room for additional capacitors too!
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline tiono  
#137 Posted : 09 July 2019 03:38:00(UTC)
tiono

United States   
Joined: 09/02/2010(UTC)
Posts: 224
Originally Posted by: 5HorizonsRR Go to Quoted Post
The Micro JST ones are actually still pretty big. Those ones on german ebay are NICE, but a bit pricier.


You may want to get the JST ACH series, photo below, compare the size to Marklin's close coupler:
Although slightly larger than the one from german ebay, but this ACH series has locking mechanism, so it will not loose during operation.




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Offline dominator  
#138 Posted : 09 July 2019 08:56:35(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
The JST are very good. I have the 1.25 variety. You can get 20 sets for a very low price on E bay but you have to wait for them. In the situation like this, I found they were too hard to pull apart so I have eased the locking tabs on them. I don't even think they need those tabs. Certainly a hell of a lot cheaper the the others listed above. I also have 50 or so CCR's [ Current Controlling Regulators ] which will handle 50v easily yet they are so small you could get 12 of them easily on your little finger nail. Cant remember what they drop the output down to right now. I have bridge rectifiers which are nearly as small. all bought with the idea of putting LED's in a small analogue engine. Work well on the bread board. they would enable the control system on the primary carriage to be mounted easily under the carriage. Dont forget, you can wind those wires around a very small diameter rod and make them more flexible for working around the bogies. Like a telephone lead.
Dereck
Northland. NZ REMEMBER 0228 for ä
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Offline DaleSchultz  
#139 Posted : 09 July 2019 13:17:20(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
nice idea with making a small coil!
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline Minok  
#140 Posted : 10 July 2019 01:36:25(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 2,019
Location: Washington, Pacific Northwest
Originally Posted by: dominator Go to Quoted Post

I also have 50 or so CCR's [ Current Controlling Regulators ] which will handle 50v easily yet they are so small you could get 12 of them easily on your little finger nail.


Nice. Just remember though, its not the 50V input possibility, but the current/power it needs to send out that are the limiting factors, as the more current and voltage one needs to regulate, the more heat dissipation there is a need for, and tiny packages by themselves if only air-cooled don't do so well there.
Toys of tin and wood rule!
---
My Layout Thread on marklin-users.net: InterCity 1-3-4
My YouTube Channel: https://www.youtube.com/user/Minok1217/
Offline dominator  
#141 Posted : 10 July 2019 02:10:29(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
Yes , I agree with that. They [ CCR's ] were bought for putting inside a small loco with no room to spare, and to only work 6 LED's.
Dereck
Northland. NZ REMEMBER 0228 for ä
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Offline mario54i  
#142 Posted : 10 July 2019 09:47:46(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Originally Posted by: dominator Go to Quoted Post
I also have 50 or so CCR's [ Current Controlling Regulators ] which will handle 50v easily yet they are so small you could get 12 of them easily on your little finger nail.


Could you please give more information about these CCRs, e.g. part number ?
thanks

Offline dominator  
#143 Posted : 10 July 2019 11:48:27(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 747
Location: Kerikeri
I got mine from Digikey. Looks like they have 100's on their stock list. I don't know what to recommend though. this is the site we see in NZ but I think it might be an American company. Watch their freight charges though.

https://www.digikey.co.n...ion-management/734?k=ccr
Northland. NZ REMEMBER 0228 for ä
Offline mario54i  
#144 Posted : 10 July 2019 12:47:01(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Thanks
once known the part number, I found them also from Mouser, RS and Farnell that ship worldwide

Offline DaleSchultz  
#145 Posted : 10 July 2019 17:09:32(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
my friend has pointed out to me that the DC-DC converter current draw was measured when it was under very light load (the 1mA draw of the LED strip) and is thus at a small fraction of its capacity. He suggests that if the DC-Dc converter was handling all the strips in the train, it would be much more efficient. If that is the case then I think the optimal approach would be:

In baggage compartment:
Pickup-shoe -> full wave rectifier -> Capacitor+inrush resistor+bypass -> DC-DC converter
then, two wires from that running to all the other coaches that need lighting

Each coach:
2 wires -> LED strip - 2 wires

Certainly a 15mA overhead over (say) 5 or 6 coaches is negligible.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline mario54i  
#146 Posted : 10 July 2019 19:28:30(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Your DC-DC converter looks strange. I have one similar based on the MP1584 IC (bought from Amazon) and input current without load is less than 1 mA.
Offline DaleSchultz  
#147 Posted : 10 July 2019 19:36:14(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
now that my meter fuse has arrived, I will also measure a second one, and at different loads.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline mario54i  
#148 Posted : 10 July 2019 20:32:49(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 182
Location: Torino,
Originally Posted by: DaleSchultz Go to Quoted Post
now that my meter fuse has arrived, I will also measure a second one, and at different loads.


You should get something like this. Maybe not the same stepdown but likely similar



regards

Offline DaleSchultz  
#149 Posted : 10 July 2019 21:34:24(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
perhaps we are not talking about the same thing...
your graph is input mA vs output mA and looks logical.

I am talking about the actual consumption of the DC-DC converter, not its input current and I am not sure if that is the same thing. As I see it, if I connect the DC-DC converter to a power supply, its available current is only limited by the power supply. If that supply could only supply say 10mA at 12V, the DC-DC converter could put out 12mA and 8 Volts.

I am measuring the total current drawn by the DC-DC converter and its load of 1mA. Input current available is many Amps.

Power supply -> Ammeter -> DC-DC converter -> LED load -> return to Power supply.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline DaleSchultz  
#150 Posted : 11 July 2019 04:43:00(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,073
so, tonight I did a bunch of very careful measurements...

The test results

First I tested the current draw of a single strip of 12 LEDs at 7.5 Volts DC: 0.47mA

Then using a power supply set to produce 17.5 Volts DC:

Using my micro DC-DC converter (output set to 7.5V) connected to a cap and 12 LEDs: 16.7ma to 17mA
I added an additional 12 LEDs to the circuit: 17mA (it went from 16.3mA to 17mA)

I then tested a second micro DC-DC converter after setting its output to 7.5 V
No load: 38mA - yes, more than double the other DC-DC converter #1
If I added 12 LEDs it drew 41mA
It started getting very hot!

I then tested a third micro DC-DC converter after setting its output to 7.5 V
No load: 31mA - also almost double the other DC-DC converter #1
If I added 12 LEDs it drew 43mA
It also started getting very hot!

I then dug out my packet of buck converters that are much bigger than the micro one and also set its output to 7.5 V
No load: 7.44mA
If I added 12 LEDs it drew ~7.6mA
with 24 LEDs 7.83mA
with 36 LEDs 8.07mA

I also tested the current between the buck converter and the LED strip and I measured 0.58mA as the LED draw.

Here is what the two types of converters look like:

IMG_20190710_215033.jpg


My thoughts

I think the micro DC-DC converters I bought are crappy.
1. They vary from item to item in how much current they draw, 16mA, 38mA and 31mA
2. The two that draw higher mA get very hot. I would not want to install them in a train.

The LED strips of 12 LEDs are really not consuming more than 1mA (0.47mA to 0.58mA) at 7.5 V

The bigger buck converter has a much better overhead of just 7.44mA

Adding additional load to a single converter only adds the additional draw of the load, without seeming to effect the overhead of the converter.

Questions

Have others had such an experience with the micro converters? Did I just get some bad ones ?

I was really happy with their small size.








Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
thanks 1 user liked this useful post by DaleSchultz
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