I'm actually about to try that this week when parts arrive on my Godzilla. Hoping to use the magnet, bridge coil, and mecha moter as triggers.

My experiment includes high voltage diodes, voltage step down, and an octocoupler that switches on/off a separate power source for the LEDs. If all goes to plan the node system will be safe and sound.

What game are you going for and what have you learned? We should collaborate and be cautious because keeping the game safe is priority when using higher voltage. From what I hear Spike 2 is sensasitive

I suspect the task is much easier that it appears at first. (See reply from John_I below for the one resistor solution)

That seems way easier.

(Deleted in favor of John's solution below)

Actually you need just one current limiting resistor and not a voltage divider. Assuming a standard LED socket #44 bulb running at 5v and more importantly 20mA (0.020 amps).

So the old formula you might remember from high school is V=IR. (I = current, V is voltage and R is resistance)

V=IR -----> R = V/I

R = 48 / 0.02
R = 2400 ohms or 2.4 K ohms

So you just need to put a resistor of something like 2.4 Kohms in series with the LED assuming it is a standard 5 volt LED.

If you plug the numbers in right here it comes out very similar:
https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor

One last note. Use a big resistor. This resistor will be pulling a full watt of power so need a 2 watt resistor!! There are probably better ways to do this by using a trigger with a 5v output. The resistor is a brute force method.

If you wanted to be able to do a fancy light shows based on the magnet, you could use a reed switch located on the underside of the magnet as an input to a Arduino or other similar micro controller. Then, your LED light show would be independent of the power to the magnet and could continue after the magnet finishes pulsing.

https://www.explainthatstuff.com/howreedswitcheswork.html

This Reed switch has me fascinated. Is there one you used that worked well in a pinball game that you can link us to? How close do you have to mount it to the magnet?

In the case of using the moter could this 48v to 12v step down work? I think I still want to use a separate power supply with an octocoupler. Especially if I'm using multi LED strips and want to do no harm to the node system.

Some advantage to using the below products as apposed to 2watt resisters?

ebay.com link: Power Converter Regulator DC 24V 36V 48V Step Down to DC 12V 120W 10A Waterproof

Or this one

ebay.com link: Buck Converter Step Down Power Module 200W 15A DC DC 8 60V TO 1 36V

Look in the Grogu thread. There is a circuit that does exactly what you are asking for and triggers off of a rollover switch. Grogu looks terrible in the ones that trigger on lights. During multiball he keeps triggering over and over and looks spastic. Not to mention moving during attract mode. Better off not moving at all than that mess.

Here is a board that basically does what you are looking for and even has timers and cool programmable features.

https://www.amazon.com/DROK-Controller-Delay-off-0-01s-9999mins-Switching/dp/B07DFT2WDS/ref=sr_1_1_sspa

Actually, the 5V taken by the LED should be subtracted from the coil voltage 48V (although it does not make a big difference here), so R=(48V-5V)/0.02A = 2150 ohm. A 2.2k resistor would be fine, with power capacity of 1W or 2W. (48V-5V)x0.02A = 0.86W but since the LED is not on for long time, probably 1W is OK.

Reed switches are fairly sensitive. You would want to mount it on the backside of the magnet up against the central core. The orientation of the switch is important. If it is oriented with the leafs parallel to the magnetic field it probably won’t work. (You want the magnet to pull the leafs together.) I haven’t tried one in this application but I think it’s very likely that it would work. The nice thing about using it here or is it isolates Your LED from the magnet voltage. LEDs are low current. You might be able to simply use the Reed as a simple switch to turn the LED on when the magnet is active. But, the true power is in using the switch to trigger a micro controller so you can do something really fancy with your light show. You could also use a hall switch. But this is a tiny bit more complicated.

https://maker.pro/arduino/tutorial/how-to-use-a-hall-effect-sensor-with-arduino