View Full Version : Reed switches


Mike(^RacerX^)
11-11-2006, 01:45 AM
Ive given up on trying to get my LapTimer 2000 software to work with the light sensors.I already tried dead striips,and that ended up being about 10 hours of my life that I'll never get back.

I want to give the magnetic reed switches a go.I heard a lot of good about them.

I remember someone gave me a part number for them a year or so ago,but I lost the info in my HD changeover.

Swamper Gene,I think it was you that gave me the info???

At any rate,if someone out there could ponit me in a direction to the reed switches,Id be greatful.

Also,any thoughts or tips or experience with them would be appreciated as well.

Mike

Hornet
11-11-2006, 02:40 AM
Mike i've been using "Miniatronics Corp" magnetic reed switches "N" scale,they're a 5/8" long normally open reed,model # 32-N58-05.
I get them at my local train/hobby store,any good hobby shop into trains should have them in stock,they come in a package of 5,and they also come with a neo magnet,either a round flat neo magnet,or a bar neo magnet,i usually get the packages with the bar neo mag's.
I mount them facing up,and i just glue them to the bottom of the track,have flush mounted them,but they seem to be sensitive enough not to need to be flush mounted,my current track has them glued to the bottom of the track,and they still count T-Jets no problem.
I glue 2 to each lane,i glue one to one inside rail,and the other i offset by about 1/2" and glue to the inside of the other rail,i'm not sure you need to do them like that,but that's the way i've done them on the last couple of tracks i've built,i think i'm anal though, :thumbsup: :p

Hornet
11-11-2006, 11:50 AM
Mike :follow Gene's advice on using a nail head,glued between the reed switches,i'm hoping Gene still has his picture showing how he does the nail trick.

wheelszk
11-12-2006, 10:36 AM
Mike :follow Gene's advice on using a nail head,glued between the reed switches,i'm hoping Gene still has his picture showing how he does the nail trick.

Mike, Gene is away this weekend, will make sure he sees this. :wave:

Mike(^RacerX^)
11-12-2006, 01:12 PM
Rick,that Miniatronics Corp has some pretty good stuff on their website:

http://www.miniatronics.com/Merchant2/merchant.mvc

To ask an incredibly stupid question,in all of my years of tinkering with things electronic,Ive never encountered reed switches.
Am I correct in assuming that the magnets from the car running over the switch is what closes it and triggers the lap counter??????

Wheelszk,thanks for relaying the message to Gene.He comes up with some incredibly clever solutions tosome of these little slot car problems that come along.

Mike

Hornet
11-12-2006, 02:40 PM
That's exactly what they do Mike.
If you look at them closely,you can see 2 small flat bars inside the glass,and when the magnets pass over them,they close the switch.
That's the first time i've looked at Minitronics web site,boy they do have some nice stuff, although punching in the switch numbers didn't look to promising,i sure hope they're still making or getting the switches.
I got nothing but respect for Gene,some of his oddball ideas/tips work great.
Just kidding about the oddball ideas Gene :wave: :wave:
Rick

noddaz
11-12-2006, 04:02 PM
I have come up with one minor problem with reed switches...
My G3 sometimes trips more than one lane when passing over them.
I would have to assume that other powerful magnet cars form Wizzard & Slottech may do the same.
It is one thing to watch out for.
Or maybe some one has a fix for that...?
Scott

Hornet
11-12-2006, 09:34 PM
Where and how have you got them placed Scott.
I run nothing but R/O cars and the odd drop in neo car,and where i have mine placed on the inside of the rails,i've never had a problem with another car in another lane tripping them.
Alot of guys end up with them slanted a bit,and that could contribute to the tripping problem if they were facing towards another lane on a slight angle.
I learned the hard way,to make sure they run dead parrallel with the lane and make sure they face upwards vertically.
I used to have the odd problem with a crashed car sliding past them and tripping them,but after implementing Gene's idea of the nail head/washer,that seems to have cured most of that problem
And handle them very carefully as they are fragile little buggers :(
Rick

SwamperGene
11-12-2006, 10:00 PM
LOL Rick. :p

Yes, this is my official overly-sensitive reed switch fix. The reeds you guys are talking about are the one's, they are sensitive enough to "see" a bone-stock T-Jet even when mounted underneath plastic track. Of course, the problem is that stronger magnet cars will trigger adjacent lanes. Well, this trick nailed it, literally. I hot-glue the reeds to the bottom of the track surface between the inboard slot and rail of each lane, flat surface of reeds parallel to track surface. Then, I grind the head off a ten-penny nail and glue it to the bottom of the track surface, centered between the lanes and on-center with the reed's contact points. Looks sorta like this (read on below the pic):

http://i12.tinypic.com/4m34p6x.gif

This is really a very simple and effective trick...the nail acts as a flux collector, absorbing any stray lines a passing car may give. I've run a full polymer T1 on every lane without a single false lap. This setup, used on my 4-lane Tomy track, has seen 10's of thousands of laps without a hitch. I have each lane's reed in the same position on the track sections, so I can have a true start-finish line that is centered over the reeds and works equally well in both directions. This brings up a tip...trim the legs of the reeds down to about a half-inch or so, they are magnetic and can trigger the reed before the car actually crosses it. Also, to make things easy solder your wires to the reeds before mounting them, then for port safety cut one wire 3" or so from the reed and solder in a 100-ohm series resistor. When done gluing the components to the track, I hot-glue the whole mess up to where the wires will drop through the table...crude but it makes a nice wire restraint. Done correctly, everything will be neatly packed in and when the wires are passed through the table the track will still sit flush.

Hope that helps ya, Mike (and Scott)!

SwamperGene
11-12-2006, 10:04 PM
Yeah Rick brings up one other point, they are very fragile...I've had them break just removing them from the tape used to package them. Before I even start messin' with them, I put a drop of hot-glue on each tip of the bulb where the wire goes through.

Hornet
11-12-2006, 10:50 PM
The longer i know you Gene,the more you amaze you :thumbsup:
For such a simple idea,it sure works,i did it to another track,and the results have been the same as at my track,a noticable drop in miss counted laps with the higher end poly and neo cars.

SwamperGene
11-12-2006, 11:05 PM
I'm amazingly simple! :lol:

BRS Hobbies
11-13-2006, 01:00 AM
Gene,

Great idea! Are you using the same reed switches that Hornet mentioned earlier in this post?

Best regards,
Brian

Mike(^RacerX^)
11-13-2006, 02:27 AM
Guys,thanks for the EXCELLENT input on the reed switches.

This will save me a lot of time and headaches for sure.

Rick and Gene,its really nice to see you guys posting over here.Now I dont have any reason to go anywhere except here on good old HT. :wave:


Mike

SwamperGene
11-13-2006, 10:05 AM
Hi Brian,

I use the "HO" reeds, same company though.


Mike....always glad to help out. :)


One more tip for the reeds....on another board there was talk of homespun magnet matching methods. You can use reeds to make one, too. Simply tape or glue a reed switch to a fixed point on a ruler, then attach the leads of an audible continuity tester to the reed. Slide the magnets slowly up the ruler until the meter beeps, noting the distance from the reed. Crude but probably as effective as washers or BB's!

Hornet
11-13-2006, 11:06 AM
Actually Gene,if you get some thin washers and a fairly long bolt,it's amazing how close you can get a set of magnets.
I use 2 bolts,one has a flat surface for doing traction magnets,and the other one i ground with a curve to match the inside of the motor magnets.
A few years back i sent a bunch of magnets out to be zapped and guass'd,by a reputable HO magnet guy,when i got them back,i matched them to guass numbers,man i couldn't get anywhere near the laptimes i'd been getting,to make a long story short,i ended up going through the whole pile and matching them with my old bolt and washer set-up,and my results were quite a bit differant then what a guass meter had given,but after matching them that way again,i was back to the old laptimes.
I actually think a bolt and washers clamped onto the whole magnet is probably more accurate then the guys doing guass'ing by freehand,you can't accurately guass a magnet unless your results are absolutely repeatable.
In the 30+ years i've been doing this hobby,i've come to the conclusion ,that you need to know basically the whole strength of the usable part of the magnet,with motor magnets that's the inside face of the magnet,and with traction magnets it's the whole face of the bottom of them.
A guass meter only can give pinpoint measurements,and with the way magnets are mixed and zapped,you can have some really strong pinpoint measurements,but the whole usable strength can be off quite a bit from another magnet
To do magnet matching properly in my opinion using a guass meter,you need a jig of some sort
But this is a topic for another thread ,and these are only my opinions:tongue:

Mike(^RacerX^)
11-14-2006, 12:27 PM
Again,thank for all of the info guys.

Rick,I use the washer method to match magnets on account of you.

It works great!!!!!! And it makes a BIG dif when you are building andtuning a car.

Id start a "magnet" thread somewhere here,but Imnot sure where to do it!!

Mike

Hornet
11-14-2006, 02:02 PM
Thanks Mike :thumbsup:
I actually have to give credit to Bob Lincoln of WizzardHO for that idea,years ago he clued me into this way of checking magnets.