How To Make More Automated Flaggers

They Are Unique and NOT Commerically Available

Model railroaders have nothing on us slotters when it comes to details and automation. Rube Goldberg was our first venture into automated flaggers. Here's two new variations, all operational at YMR. They are much simpler, with fewer moving parts.


"Lukinder Mirros", YMR's push button operated Blue Flagger.

Lukinder is manually operated via a push button located near the race coordinator's station and SPTS computer console. When you push the button, power is supplied to a 12 volt motor under the table which spins the blue flag in his hand. This is the simplest automated flagger you can build. A variable resistor is built into the circuit to allow you to regulate the current which controls the RPM (revolutions per minute) of the motor and the speed of the flag waving.




"Tex Watkins", YMR's computer controlled Chief Flagger.
He takes his commands from SPTS
and will be waving his flag as you round the last corner
to cross the finish line and win your race.

Click Here for Mechanical Diagram of Flaggers

The Motor

You need a 12 volt motor to drive the flag. You are probably thinking that you have a spare slot car motor somewhere. The problem with slot car motors is that they are designed to operate at very high RPM so it causes the flag to twirl too fast. The best motor is a slow RPM motor. A great place to find these motors is in old broken VCR's. These motors are used to drive the mechanisms in the VCR that turn the tape. They operate just like slot car motors but at slower speeds.

The Bushings

Friction will severly hamper operation. To eliminate (most) friction, drill the hole thru the table for the piano wire and press fit a small brass tube (available at all hobby stores). The inner diameter of this brass bushing should be several times the diameter of the piano wire. The next bushing needed is for the flagger's wrist. I cut a small length of the same brass tube, put three or four wraps of single strand copper wire around it, then twisted the ends of wire around each other to form a "handle". Once soldered, snip off the excess length and epoxy the "handle" into the flagger's waving arm (see below). The two bushings should line up (of course) so that the paino wire turns freely.

The Track Figure

Next, scrounge up one of your 1/32nd scale plastic track figures. The rigid styrene type are preferable to the plastic soldiers as they flex less. Cut off the waving hand (ouch!) and drill a hole down the figure's arm with a very small drill bit. You can then epoxy the brass bushing "handle" that you made above, ensuring that the bushing lines up perpendicular to the table surface. The piano wire drive shaft is going to come straight up thru the table and thru the bushing. Once the brass wrist bushing is painted flesh colour, you'll never know its not an original part. The wire wraps around the bushing even look like fingers for those of you that are not bifocal challenged. During final installation, the track figure should be firmly secured to the table top, once everything is aligned.

Mounting the Motor

The motor has to be securely mounted under the table. The motors I used were cylindrical, so I just drilled a hole in a piece of scrap plexiglass the same size as the diameter of the motor, and epoxied the motor to the plexiglass. Two screws hold the plexiglass to a small block of wood glued under the table. If you drill the holes in the plexiglass several sizes too large and use a washer for the screws, you should have lots of play that you can use to align the motor shaft with the hole in the table.

The Drive Shaft

It's just thin piano wire, available at all hobby stores. It's also useful for lining up the bushings and the motor. I used a small piece of plastic tubing, half pressed over the armature of the motor. This left half of the plastic tubing open so the wire just sits inside it. By doubling over the end of the paino wire, you can make a nice (non permanent) friction fit.

The Flag

For a chequered flag, I made one up on the computer, printed it, and glued it around the piano wire. For soid colour flags, I used a piece of masking tape, folded around the wire, and painted with my regular model paints. Cut off all the excess wire when installed, except for about 1/4 inch at the top. I use pliers and fold this short length back down, so that it helps give mechancial grip to the flag.

The Variable Resistor

This simply controls the amount of 12 volt current that goes to the motor. This controls the speed and allows you to slow down or speed up the motion of the flagger. Your slot car controller is a variable resistor, also referred to as a Potentiometer. You will have to experiment with a few as they need to be mated to the motor that you scavenged. Radio Shack has bundles of assorted potentiometers or "trimmers". The VCR that you took apart to get the motors will have several in it too, that's where I got mine (Talk about being a real cheapskate!!).

The Wiring

There are two methods of wiring, depending on the control method you use.

For the simplest Push Button Controlled method, refer to the Mechanical Diagram above. It's about as simple as it gets. Take the power from an accessory supply, not the main slot car power supply, You don't want to affect the performance of your race cars when you "Hit the Button".

For the more complex Computer Controlled method, you need to refer to a separate wiring diagram. (It's a little scary if you cut too many classes at high school... but easily do-able if you follow the SPTS instructions). The computer supplies a 5 volt signal via the LPT Port to a transistor which activates the 12 volt circuit for the motor. There are several diodes to protect your precious computer port from short circuits. Naturally, you will need a computer program to send the right signals to your flagger at the right time. You can spend months developing your own, or you can install our Simple PhotoCell Timing System. The wiring diagram is also included in the SPTS Installation Instructions.

Click Here for Computer Controlled Wiring Diagram

How Does "Tex" Know When to Wave His Flag?

He doesn't just wave when you finish the race, he knows that you are on your last lap and thru a highly complex set of Einsteinian calculations, he predicts your arrival and starts waving vigorously when you are about two corners from the finish line, regardless of the length of your track. "Tex" wants you to get the full rush of victory and he stops only when you cross the line. "Tex " just knows.

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