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Using moving-coil meters as PWM-controlled gauges

You should definitely take in account such device as moving-coil ammeter, widely known for more than 100 years as D'Arsonval galvanometer (which is a moving coil of wire rotated in radial magnetic field).

This meter is very commonly used in various instruments based on current measurement (ammeters, voltmeters, ohmmeters). You can get more information about it yourself.

Moving coil meters can be easily used in your cockpit simulator for many instruments: engine and fuel gauges, electric systems indicators, VOR and glide slope needles, and any others with suitable deflection range (moving-coil ammeters may have needle deflection from 90 to 200+ degrees).

Choosing a moving-coil meter

You can find some of the ammeters or voltmeters that can be used without any alteration, except the faceplate for your gauge and the needle (you can just glue your custom needle directly to the meter's needle).

You should pay attention to maximum deflection range - if this is an ammeter, it can be 1 ... 100 mA, if this is a voltmeter, the maximum measuring value should be 1 .. 5V. If you have the meters with these ranges you can use them without reworking:

Typically, an ammeter without any shunts inside may have full scale deflection at current of 0.1 to 1mA. If you have an ammeter, for example, with 5A range, you can use it too, but you need to open it and remove the shunt inside (generally, it is just a wire resistor).

It's an easy and convinient way to make some of the engine instruments, electric indcators, some fuel gauges and other instruments that have a limited needle rotation angle (moving-coil ammeters can have the scale varied from 90 to 200 degrees).

Before using your coil gauge you need to know its milliammeter characteristics and calibrate it using resisors/potentiometers.



Read here about connection options       >>>

Video - example of using an old ammeter as PWM gauge controlled by RPM dataref from ARDref plugin (I've used a single potentiometer to adjust the gauge range):


You can notice that the coil meter is moving very smoothly, without jerking and noise (zero noise) and it's very similar to the real gauge in comparison to servo-driven gauges.


PWM driver, TLC5947 breakout board pinots:


Linear bar graph displays (analog signal meters)

Along with digitally controlled LED bar displays (described here), you can use some of analog LED bar display modules with built-in drivers (like LM3914N) which are controlled by voltage and can be used with PWM outputs.










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