Layout Pictures

LED Tail Fin Light Conversion!

Created 5/5/2010

Special Thanks to T.John!

ADDING or CONVERTING SCHUCO MONORAILS to LED's

1. You will need two pointed LED's for the tail fins and one large LED for the center light. To create the pointed LED's, start with two 3mm LED's, tie or tape the leads of the LED, and put it nose first into a motor tool or drill motor. Using a small file or sanding stick, turn down the ridge at the base of the LED. Turn the LED around and trun down the LED to a point, finishing it using 400 and 600 grit sand paper. Coat the LED with a clear coat. The large LED is a 5mm LED with the rim turned down just like the pointed LED's. If you wish to use a white LED for the headlight, a 5mm LED is prepared the same way the red LED has been done with the ridge turned down. I then lengthen the LED body with a little epoxy in a tape mold to make it the same length as the old lights.

2. To Power the LED's, we can go with a simple diode and resistor, or we can go complex using a voltage regulator.

SIMPLE: The resistor for the red LED using a standard HO power pack would be 720 ohms. If you are lucky enough to have a Schuco power pack (#150), you need to use 1200 ohms or 1.2K. The LED needs to be protected from a high reverse voltage, so a rectifier diode needs to be placed in the circuit. There are two ways of wiring the components: One, with all parts in a series; the other with the diode reversed in parallel with the LED. The series circuit allows you to use a singe diode for all three red LED's, but each needs it's own resistor.

COMPLEX: A more complex way is to use a LM317 voltage regulator to reduce the voltage to a constant voltage to power the LED's. You still need a rectifier diode and two resistors to set the voltage, and you still need individual ballast resistors to control the LED's. The advantage is that now the brightness does not vary once the input voltage is above that required for the regulator to work. It takes about 2.5 volts over head for the regulator to work, so to regulate 1.5 volts, you need the input to be above 4.0 volts. Adding a capacitor to the input will allow a steady input power while the power pickups skip on the track. The LM317 can take up to 40 volts at the input, and supply the programmed voltage out. If a capacitor is used, the voltage rating must exceed the actual voltage or it may fail.

The last resistor needs to be calculated for voltage and LED.

For example: 3.4 V out minus the forward voltage of a red LED 2.2 divided by .015 equals 80 ohms. The nearest standard resistor value will work fine.

The following are typical forward voltages of the various colors of LED's:

Original Red LED--1.7 volts

Red, Yellow, and Yellow Green--2.2 volts

Blue, True Green, Blue Green, all Whites, UV, and Purple are all 3.2 to 3.4 volts.

Doug's Note: That is the information I have. Let me know if any of you try this. I have not been brave enough to do so, so won't be any help if you need it. I have also talked to some model railroaders who put strobe lights on cars, etc. Wouldn't it be neat to have a strobe light on the top of the power unit? Also, adding capacitors to even the old style of lighting would be cool!! Maybe I will try that at some time, IF it is possible.

Back to Home Page

Back to KEEPING YOUR MONORAILS RUNNING page


	COMPLEX: A more complex way is to use a LM317 voltage regulator to reduce the voltage to a constant voltage to power the LED's. You still need a rectifier diode and two resistors to set the voltage, and you still need individual ballast resistors to control the LED's. The advantage is that now the brightness does not vary once the input voltage is above that required for the regulator to work. It takes about 2.5 volts over head for the regulator to work, so to regulate 1.5 volts, you need the input to be above 4.0 volts. Adding a capacitor to the input will allow a steady input power while the power pickups skip on the track. The LM317 can take up to 40 volts at the input, and supply the programmed voltage out. If a capacitor is used, the voltage rating must exceed the actual voltage or it may fail.


	The last resistor needs to be calculated for voltage and LED.


	Doug's Note: That is the information I have. Let me know if any of you try this. I have not been brave enough to do so, so won't be any help if you need it. I have also talked to some model railroaders who put strobe lights on cars, etc. Wouldn't it be neat to have a strobe light on the top of the power unit? Also, adding capacitors to even the old style of lighting would be cool!! Maybe I will try that at some time, IF it is possible.