I'm working on converting some passenger cars to LEDs. I've been running them on AC power and want to run them on DC power. I know that I can (and will use) GRJs LED board, but want to try rolling my own too. I found the following parts (I don't mind spending more $$ as I don't want to wait from orders from overseas to show up) I not worried about capacitors or pots to control the brightness in the cars. Let me know if this stuff will work and/or suggestions.
3. Choke
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If you scroll down through this thread, I believe you'll find all of your questions answered, including one or two you have not yet asked:
Are you running conventional or command control with your DC track voltage?
And are you planning on using the popular 12V LED strips?
If conventional DC, many DC engines creep along fine at less than 10V - but this is not enough voltage to light 12V LED strips with your other components installed.
If low voltage DC operation is important, there are also 5V LED strips...or you can modify a 12V LED strip by shorting out every 3rd LED. This makes it a 9V LED strip.
stan2004 posted:Are you running conventional or command control with your DC track voltage?
And are you planning on using the popular 12V LED strips?
If conventional DC, many DC engines creep along fine at less than 10V - but this is not enough voltage to light 12V LED strips with your other components installed.
If low voltage DC operation is important, there are also 5V LED strips...or you can modify a 12V LED strip by shorting out every 3rd LED. This makes it a 9V LED strip.
Currently I'm running command engines but want to have the flexibility to run both command and conventional (AC using legacy and DCS) Using the 12V LED strips.
Pingman posted:If you scroll down through this thread, I believe you'll find all of your questions answered, including one or two you have not yet asked:
Thank you.
One way to handle the traditional LED strips with three LED's and the resistor in the group is to simply short out the resistor, that also makes it a 9V strip, but preserves all the lights. This will allow the strip to light using my constant current regulator boards down to about 7 VAC on the tracks. That should cover most conventional operation.
gunrunnerjohn posted:One way to handle the traditional LED strips with three LED's and the resistor in the group is to simply short out the resistor, that also makes it a 9V strip, but preserves all the lights. This will allow the strip to light using my constant current regulator boards down to about 7 VAC on the tracks. That should cover most conventional operation.
Sweet. Forgive me for asking this but how do you short out a resistor?
The indicated spots are the resistors in the 3-LED groups. Using a 500F soldering iron, just "sweep" them off the pads by applying heat to the side, the ceramic base will conduct the heat to both pads and remove the resistor. Solder a small jumper across the pads, I use #30 solid wire-wrap wire for the task.
gunrunnerjohn posted:The indicated spots are the resistors in the 3-LED groups. Using a 500F soldering iron, just "sweep" them off the pads by applying heat to the side, the ceramic base will conduct the heat to both pads and remove the resistor. Solder a small jumper across the pads, I use #30 solid wire-wrap wire for the task.
Alright I'll try that.
Trainlover9943 posted:I'm working on converting some passenger cars to LEDs. I've been running them on AC power and want to run them on DC power.
Just to be clear, when you say DC power do you mean DC power on the track (like HO or G) or that you want to power the LEDs with DC power?
If you want to roll your own, here's the circuit I use on my PCB. It's tried-n-true, and being a constant current design, you can tinker with the number of LED's in the groups. If three don't light at a low enough voltage, short an LED in each group and leave groups of two, that will allow operation down to less than 5VAC on the tracks.
stan2004 posted:Trainlover9943 posted:I'm working on converting some passenger cars to LEDs. I've been running them on AC power and want to run them on DC power.
Just to be clear, when you say DC power do you mean DC power on the track (like HO or G) or that you want to power the LEDs with DC power?
DC power for the LEDs. AC for track power. My bad
Trainlover9943 posted:...I know that I can (and will use) GRJs LED board, but want to try rolling my own too. I found the following parts (I don't mind spending more $$ as I don't want to wait from orders from overseas to show up) I not worried about capacitors or pots to control the brightness in the cars. Let me know if this stuff will work and/or suggestions.
When you say roll-your-own, do you mean duplicating GRJ's circuit (which he posted above) or are you imagining other lighting features other than simply driving the 12V DC LED strip?
Point being the "Voltage Regulator" IC chip you refer to is actually being used as a Current regulator in GRJ's design. This may be tomato-tomahto to some, but when GRJ's board was in the design phase, there was some back-and-forth as to which way to go (Voltage mode vs. Current mode). Your IC chip can be configured either way. If you are only going to drive the 12V LED strip (modified as needed for reduced-voltage conventional operation) by all means use GRJ's board.
But if by roll-your-own you mean to provision for other electronic features in your passenger car, you may want to consider configuring the regulator IC chip in Voltage mode which costs you a 1-cent resistor. You might want to add, say, a blinking/flashing light module, or some small animation motor, or remote-controllability to turn lights on/off in sync with the engine's cab light, or you get the idea.
In my interpretation of history, after GRJ unleashed his board on the world, there was no need for anyone to re-invent the wheel. So when I see someone/anyone asking about rolling-their-own, I'm curious to know what they have up their sleeves!
stan2004 posted:Trainlover9943 posted:...I know that I can (and will use) GRJs LED board, but want to try rolling my own too. I found the following parts (I don't mind spending more $$ as I don't want to wait from orders from overseas to show up) I not worried about capacitors or pots to control the brightness in the cars. Let me know if this stuff will work and/or suggestions.
When you say roll-your-own, do you mean duplicating GRJ's circuit (which he posted above) or are you imagining other lighting features other than simply driving the 12V DC LED strip?
Point being the "Voltage Regulator" IC chip you refer to is actually being used as a Current regulator in GRJ's design. This may be tomato-tomahto to some, but when GRJ's board was in the design phase, there was some back-and-forth as to which way to go (Voltage mode vs. Current mode). Your IC chip can be configured either way. If you are only going to drive the 12V LED strip (modified as needed for reduced-voltage conventional operation) by all means use GRJ's board.
But if by roll-your-own you mean to provision for other electronic features in your passenger car, you may want to consider configuring the regulator IC chip in Voltage mode which costs you a 1-cent resistor. You might want to add, say, a blinking/flashing light module, or some small animation motor, or remote-controllability to turn lights on/off in sync with the engine's cab light, or you get the idea.
In my interpretation of history, after GRJ unleashed his board on the world, there was no need for anyone to re-invent the wheel. So when I see someone/anyone asking about rolling-their-own, I'm curious to know what they have up their sleeves!
Basically I want to just duplicate GRJs board. I'd love to do things like operating MARS lights in the back for observation cars and automatic control of headlights/tailights in subway cars but that's a project for a later time.
FWIW, I routinely add markers and rear facing lights with discrete LED's using the same power power source. If you used something like the www.ngineering.com MARS simulator, I'm pretty sure you could also use a proper balancing resistor to power it from the same power, I've just never had the need for a rear facing MARS light.
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