Vane Displays

What is a vane display?

A vane display is a type of seven-segment display that uses physical segments that rotate on an axis to show numbers. These segments, called vanes, rotate into view to turn on, or out of view to turn off.

Beneath the vanes, there are electromagnetic coils that rotate permanent magnets to move the vanes as necessary. When powered by a pulse of current, usually at 12 volts DC in either direction, the electromagnetic field on the powered coil changes polarity, thus rotating the selected vane. No power is needed to retain the displayed number, meaning this is a very eco-friendly display type.

What sizes of vane display are available?

Vane displays come in a variety of sizes. These come in 1.5", 4", 6", 9", 12", 18", and 24" sizes, meaning you'd have a size for any application, be it a toll booth, a sports scoreboard, or a simple wall clock.

How can these be mounted in a case?

There are different ways to mount a vane display depending on its size. Staver made suggestions on their old website from 2000 to mount as suggested in the following quotes below...

For the 1.5" size 152L:

This model should not be handled by the coils or damage to the high resistance wire can occur. PCB holes should be no less than 0.05" in diameter and arranged so negligible pressure is placed on the coil terminals when they are inserted into the printed circuit board. After soldering, carefully inspect the metal outer mask to ensure that it has not slipped out of position.

For the 4" size 402L and 6" size 602L:

Mount on threaded PCB standoffs. Insert standoffs into a guide rail mounted in the case.

For the 9" size 900L, 12" size 1200L, and 18" size economy-grade 1820L:

These displays are constructed on a plastic base plate. Plastic materials have about ten times the thermal expansion rate of metals. The difference between summer and winter temperatures for outdoor installations can cause significant changes in the dimensions between mounting holes. At the maximum working temperature limits of -40°F to +170°F, the 900L vertical mounting distance, nominally 8", can change 0.08", and model 1200L can change 0.11" between the two temperature extremes.

If these displays are rigidly mounted, the back plates will warp. To compensate for thermal expansion, these models are manufactured with large mounting holes and shipped with special loose fitting mounting bushings that are inserted into the holes on the back plate. These mounting fittings must be used.

For the 18" size 1810L and 24" size 2410L:

Mount case in sign with rubber washers. Because of the aluminum construction, these models can be mounted more rigidly.

How would I get one of these to run?

Staver recommends using the CD4543 CMOS decoder to send data to the display through a series-connected pair of Darlington arrays. Depending on the size of the display, you would need the ULN2004 for displays under 18" height or paired ULN2067B arrays for 18" or 24" height.

Diodes are a necessity for driving these displays. They will prevent backfeeding current and also catch flyback voltage from the coils when the pulse current is released. Use 1N4004 diodes for displays under 18" or 1N5401 diodes for 18" or 24" size. Be sure to point the cathodes away from the coils, and also toward the positive supply on the Darlington transistors on the pulse drivers.

For the common pulse drivers, we will need a small signal NPN transistor and a PNP Darlington power transistor chained together for each driver. The NPN can be a 2N5172, BC109, or any NPN you wish to use. Place a 10k resistor at the base. The collector of this transistor goes out to a 1k resistor in series with the base of the PNP Darlington, which will either be a TIP115 for smaller displays than 18" or a TIP127 for 18" or 24" size displays.

The pulse signal should be set to a minimum of a set amount of time per model. See the table below...

Model Number	Pulse Length
152L	30ms
402L	50ms
602L	90ms
900L	150ms
1200L	200ms
1810L	300ms
1820L	350ms
2410L	400ms

Connect the entire circuit to 15 volts DC, and connect the orange lines of the display to the set signals and red lines to the reset signals. The set signals are between the Darlington stages, and the reset signals are after the second stage. Then send a pulse signal through all of the 10k resistors, and BCD into the decoders. The display should flip to show the desired number.

Source of citation: Staver Company, Application Notes. Archived October 26, 2000.