Topcat1707821625 Posted January 18, 2023 Share Posted January 18, 2023 I don't see that locos causing radios to crackle is relevant to this subject. This is radio frequency interference that any inadequately suppressed motor will cause, but it will have no effect on a reed switch. Obviously a motor has a magnetic field, but as far as possible it is a closed circuit as leakage of the field makes the motor inefficient. I think a loco would have to be quite close to a reed switch to operate it.What the earth's magnetic field has to do with the matter I have no idea. Its strength is around 50 microteslas and will have not the slightest effect on a reed switch.By comparison permanent magnets will have strengths of hundreds of milliteslas and even over 1 Tesla for some neodymium magnets. Link to comment Share on other sites More sharing options...
What About The Bee Posted January 18, 2023 Share Posted January 18, 2023 Correct Topcat. The earth's magnetic field will not affect a reed switch.But if the Airfix locomotive affects the compass, we know that there is a magnetic field developed by that locomotive. Which, if strong enough, will change the state of a reed switch.BeeEdit to add: the east-west orientation is to make the magnetic field of the locomotive orthagonal to the earth's magnetic field. This will provide greatest sensitivity to a potential magnetic field of the loco. Link to comment Share on other sites More sharing options...
96RAF Posted January 18, 2023 Share Posted January 18, 2023 I thought we had sussed that it was JJs nearby old controller that was doing this. Link to comment Share on other sites More sharing options...
Potterton Posted January 18, 2023 Share Posted January 18, 2023 Yes 96RAF, I thought that as well.However.........I use a similar system to the Hornby Maglight, though mine is home made in that I bought a 5 metre strip of LEDs and cut off the required number for each application, (e.g. a full length coach or a six wheeler, etc), connected to a button cell battery and operated via a latching reed switch. I also use the same system to operate tail lamps and have noticed that these can be switched on or off by certain passing locomotives or by the guards van, (for example), passing certain "parked up" locomotives. The "worst offenders" as it were are the Tri-ang Hornby Blue Pullmans dating from the 1960's so I assume these units have stronger magnets in them than more modern stock. Surprisingly it doesn't happen when other locos manufactured around the same time pass within the same proximity. Link to comment Share on other sites More sharing options...
JJ73 Posted January 19, 2023 Share Posted January 19, 2023 @ TC - No probs - what you are doing sounds interesting!!! Glad my Video help you to decide not to use reed switches!!! 🤔@ BB :- Thank you for watching my video (again)!!! I didn't think about or thought that having the Maglight Carriages a certain way round would matter!!!@ Bee :- That sounds interesting aswell - I do have a compass some where - not sure where thou???@ Raf:- Yes I remember us saying something like that aswell!!!@ every one else :- Yes a few of my older Locos do have may be a strong magnet in them!!! 🤔🚂 Link to comment Share on other sites More sharing options...
What About The Bee Posted January 19, 2023 Share Posted January 19, 2023 Hi JJI would place the compass on the roof of the carriage, directly over the reed switch. The idea is really quite simple. A compass is sensitive to the tiny magnetic field of the earth. In the absence of other magnetic fields, the compass will point to the earth's magnetic north pole. So if another field is present and not aligned to the earth's pole, the compass needle will move.Where do you want to see if there is a magnetic field? At the switch! So put the compass there.You can easily isolate which component is generating that magnetic field by moving a component closer to and further away from your maglight, checking to see if the compass needle moves.BeeA compass is an incredibly inexpensive magnetometer. It won't tell you the field strength, but it absolutely will tell you if there is a magnetic field present, or not. Link to comment Share on other sites More sharing options...
Topcat1707821625 Posted January 19, 2023 Share Posted January 19, 2023 Some developments in my coach lighting system.As mentioned in a previous reply I am developing a coach lighting system that I hope will overcome most of the drawbacks of other systems. The control electronics and battery will be mounted in a brake composite coach and power will be distributed to lighting in the other coaches. I originally thought of using JST micro connectors to interconnect the coaches but decided that this it would be too fiddly to connect these between up to 6 coaches as well as connecting the normal couplings.I have just built the first two (fairly crude) prototypes of my magnetic coupling connectors, which couple the coaches both mechanically and electrically. They will withstand a force of up to 3.5 Newtons (350 gm) before the connection breaks, which is much higher than the tractive effort of any loco. The next steps is to fit them in two coaches with the rear one loaded heavily and see how they cope with starting forces. If all goes well I will then fit the couplings and coach lighting to several coaches. Link to comment Share on other sites More sharing options...
JJ73 Posted January 19, 2023 Share Posted January 19, 2023 Found it Bee!!!Here are some photos of the Compass on top of the Maglight Carriages!!! As you can see in both Photos...True north is pointing towards the bottom of the photo, but yet the needle is pointing near the West / South East position!!! Link to comment Share on other sites More sharing options...
M. Matthews Posted January 19, 2023 Share Posted January 19, 2023 I just picked up a couple of the longer strips for mk3 coaches to light up one of my DMU’s. It doesn’t seem nearly long enough to light the whole coach? Link to comment Share on other sites More sharing options...
What About The Bee Posted January 19, 2023 Share Posted January 19, 2023 JJNow what device did you energize to cause the needle to shift?Be careful to isolate the needle shift to just the one, as there may be more than one device nearby. As RAF stated, it may be your controller. Perhaps, as you show on the video, its the Airfix locomotive.If nothing is on, you have another magnetic source nearby, perhaps in the carriage itself. You now have the tool, excellent. Now find the culprit!Bee Link to comment Share on other sites More sharing options...
JJ73 Posted January 20, 2023 Share Posted January 20, 2023 Now then Bee...I have 2 Controllers I use :- The H & M Duette & the 2000 but was simply the Maglight Carriages what made the needle to shift, but in saying that as you can see in the photo below, I have found at least 5 yes 5 culprits!!! ( I may have more hiding amongst my many Locos!!!) 2 of my 0-6-0 Jinty's, 2 of my 2-6-0 GW Tank Locos & as displaying at the back 1 of my B17 (As long as they got a Strong Magnet & on the Same Track as the Maglight Carriage & the power is switched on) then they will turn on the Light on the Carriage - Case Closed!!! 😉🚂 Link to comment Share on other sites More sharing options...
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