Refrigerator Sound, Battery Operated by a Switch with Piezo Buzzer or...

I can’t help you as far as the buzzer or what battery or voltage requirements. I have been working on my caboose fleet. Really don’t care for lighted interiors. Just want the lit Tomar lanterns. I could get them to work without flickering with track power.   What I wanted was a way to easily shut them off when not in service. I’m trying out battery power. I bought a circuit board from Polulu.

I wired it voltage IN and Out with battery power and adjusted the output to match my lights. The A&B can be run to a magnetic reed switch that you can secure inside the cars rooftop. I just use a paint stirring stick with a couple of small magnets glued to it. One pass over the car turns it on. Another pass turns it off. Seems to work really well. I read about this many years ago. Didn’t know anything about electronics so I just passed. Got interested in the idea again when I read up on Rapidos passenger cars with their magic wand lighting. The Polulu  board info. I found on a Forum thread about converting locos to battery power.

@Dave_C posted:

I can’t help you as far as the buzzer or what battery or voltage requirements. I have been working on my caboose fleet. Really don’t care for lighted interiors. Just want the lit Tomar lanterns. I could get them to work without flickering with track power.   What I wanted was a way to easily shut them off when not in service. I’m trying out battery power. I bought a circuit board from Polulu.

If they're powered with track power, why worry about the switch?

@EastonO posted:

Many, and I mean many years ago, I read a model train article about how to build a simple electrical circuit using a piezo buzzer operated by a battery and the switch on the bottom of a refrigerator car for a refrigerator sound. There was a different size battery and different size buzzer depending on gauge. So, I'm looking for that article or, a circuit to build or buy that fits in an O refrigerator car, battery or track powered. Researched this and haven't found anything.

If you want a continuous sound track, a simple sound board will give you a realistic reefer sound.  You can power it from track voltage and do the whole job for a few bucks.

John, the trucks I’m using on one of them are mean’t for 2 rail. I replaced the wheelsets but there’s really not room for a pickup roller. Figured I’d try battery power. It’s just a matter of how long the battery lasts. When they aren’t in service I prefer the lights off.
The switch I’m using could also be used with track power. I find the magnet passing over is easier to use than fishing for a toggle or slide switch.

I agree with the magnet, I use a reed switch on some of my very small motorized vehicles for the PGM/RUN switch.  I have a tiny magnet stuck to the bottom of the vehicle so I always have something to energize the switch if I need to program the unit.

The red circle is the reed switch inside the cab, the arrow points to the magnet stuck to a screw head.