Circuit for Loco Lamps/Smoke Generator - Advice Needed

[A.R.]

Hi all, 

 

I know there are many an electrical whiz on this wonderful forum and therefore I am looking for a little help if I may. I am looking to install loco lamps and a smoke generator in an 8F. I use DC and I would be very greatful if someone could check my circuit diagram below!

 

I am aiming for the following setup:

• To be able to switch all lights and smoke generator on and off (for this I am using a small radio transmiter and reciever)
• To be able to switch the lights between (front/white, rear/red) and (front/red, rear/white) via a magnetic reed switch. 

 

I look forward to hearing your thoughts and any help/advice would be warmly recieved!

 

Kindest regards, 

 

Alex R

[John ks]

Having  LEDs  in series that are different colours (IE one white & one red ) can result in the brightness's being unequal

Adjusting the resistor value to get one LED at a pleasing brightness may result in the other LED being to bright or to dull

 

If you connect the LEDs (with series resistor ) in parallel (as shown in the altered drawing) then you can adjust the resistor value the get the best brightness for each LED

 

 

Regarding the reed Sw & Latching relay

As far as I know Reed switches are only closed when in a magnetic field

 

If the relay latches with a pulse from the reed sw & unlatches with a second pulse then you should be OK

 

If the latching relay doesn't work as described above then how do you unlatch the relay?

 

John

 

 

 

[cliff park]

It is possible to make a reed relay latching, but a bit of a faff. If you  (carefully) position a small magnet close to the reed, but not close enough to operate it, then when another magnet comes along it will close and stay closed when the operating magnet has gone, held there by the weak field of the bias magnet. It then needs a magnet of the opposite polarity to release it. This principle can also be used to selectively operate the reed since a magnet of the wrong polarity will not operate the reed against the bias magnet, so for instance some locos will operate it, some will not, some will release it, some will not. Note that generally speaking magnets need to be in parallel with reed and bias magnets in parallel, but at a distance. Another possibility is for the bias magnet to be an electromagnet. Either a weak coil wrapped around the reed, or a separate coil with iron core (eg a nail) alongside  the reed. The advantage of this for the bias is that it can be turned off to release the reed by some other switch, a manual push button, another relay, or similar.

It is also possible to make a normally closed relay this way. The bias magnet or coil holds the reed(s)  closed and when a magnet of the opposite polarity is presented it will release until the operating magnet is taken away when it will operate again. Some juggling with strengths and proximity will be needed.

[A.R.]

Good afternoon, 

 

Thank you for all your help and advice, it is really appreciated and goes to show what a great place this forum is! I have taken your thoughts on board and done a bit more research (McKinley Railway do a very similar thing with tail lights in their breakvans so thanks to them for a very helpful video on that!). I have come up with the following which I think solves the issues John raised re. resistors and relays. 

 

I thank you in advance for any feedback/advice! 

 

Kindest regards, 

 

Alex R