Removing slide shoes from operating cars (formerly: "Reed switch"

The tiny relays arrived today.  They ARE tiny!  Wish I'd known of them before.  Pic below, on laptop keyboard for comparison.

That's why I use them.  5 amps in a package that size is fairly impressive.

And 10 amps if you parallel the contacts.  For the benefit of other prospective users, the terminals do not appear to be labeled, so you must download the data sheet on the Digikey website. 

I'd think that the relay's pins are NOT on 0.1" (2.54mm) centers is a nuisance?  That is, if one chooses to mount it on 0.1" grid prototyping board...

Since I use the SMT versions for the most part, that's not an issue.  For one-off stuff with the DIP versions, I just stick them on the board dead-bug style and wire to them.

RJR posted:

And 10 amps if you parallel the contacts.  For the benefit of other prospective users, the terminals do not appear to be labeled, so you must download the data sheet on the Digikey website. 

Well, that's never a great idea, even a very small difference in closing or opening can put the entire load on one contact at a critical time.

One thing to note, the coil does have polarity, they won't work if you get it backwards.

Thanks for the alert.  That's unusual for a coil.

A lot of small relays are like that, I'm thinking it's either because of internal diode protection or perhaps the armature is magnetized as well to minimize the power required to pick the relay and they have to be in sync.  I know I've wired them up backwards and they don't work.

Well I finally got around to finishing an MTH ore dump car.  Attached is a video of it operating, and a still of the bottom.  As noted above, the bulb could be replaced with an IR emitter.

Also attached is a photo of a unit with the submini relays GRJ has recommended.  Relay not yet wired up.