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Vehicle Displays

  1. Sep 4, 2013 #1

    What exactly are the things in vehicles that display different attributes of the vehicle called? Like for example in a car you have a display that tells you how fast you are going, the temperature of the engine etc.. I have to design one for a project. I suppose I can design a digital one but I think a mechanical one would be easier and cost less. I'm trying to build a low cost one. My plan is to figure out what exactly these things are called, research them, and then go from there. Like I'm not talking about the name of a specific display, like a speedometer, just what is the general thing called that has a glass cover over it, and needle that moves along something with marks on it that people can view to get information. It's a meter of some sort but what kind of meter. I need design one catered one for attributes of a airplane.


    For any help.
  2. jcsd
  3. Sep 4, 2013 #2


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    I think the general name for systems that covert information in one form to another form is "transducer".

    By "information" in this case I mean things like rotational speed, converted to a different scale on a meter or to a digital display, etc.
  4. Sep 4, 2013 #3


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    For an aircraft, you have the instrument panel that contains various instruments. Historically, you would have analog instruments for things like airspeed, altitude, engine information, a turn coordinator, etc.

    For most modern aircraft you'll generally have a "glass display", basically a digital flat panel display giving flight information. One of the more important parts of the display is the primary flight reference, displaying attitude, angle-of-attack, sideslip angle, airspeed, altitude, and other useful information giving the vehicle state. Since a lot of aircraft have fly-by-wire systems or can otherwise get needed information digitally (e.g. through the use of transducers) there's not much to argue against using digital displays. Digital instrument panels also offer more flexibility and can be used as multi-function displays (e.g. see F-35).

    One thing that you should also consider is human factors. The whole purpose of an aircraft display is to communicate information to the pilot, so you want to make sure that using your display is easy for humans. MIL-STD-1787F is the US military standard for human factors. The FAA has an Advisory Circular for human factors, but I can't remember the number. There's also a NASA standard for spacecraft human factors.
  5. Sep 5, 2013 #4


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    I think jhae gave the best generic term -- instruments.

    The advantage of mechanical instruments is that they can be easily seen in bright sunlight, and also in dim light or the dark as long as you backlight them.

    Digital instruments can be more precise, as in a digital speedometer being able to give you your speed to tenths of a kph or mph. With most digital displays, you will need to sense the ambient light level, and adjust the brightness of the display to maintain good visibility.

    What sort of instrument are you thinking of building? There are some fun new ones, like backup obstruction warning instruments, or blind spot warning instruments. You could get adventurous and use Google Glass to design a Heads-Up-Display (HUD).... :smile:
  6. Sep 6, 2013 #5


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    Each individual seperate display is also called a guage or indicator.
  7. Nov 11, 2013 #6
    The ones you are thinking of with the needles are air core gauges, or just "air cores". Wikipedia has an article about them, and calls them a type of rotary actuator.
    Do you mean low cost for (theoretical) mass production, or low cost for your project? Many people use standard servos for hobbyist instrument clusters as they are easy to get hold of and easy to control from a microcontroller.
    If you are good at software then I'd say it would be easier to make a digital instrument cluster, certainly the electronics/mechanics will be much simpler if you are allowed to run it off a laptop or something.
  8. Nov 11, 2013 #7


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    Now you can get digital gauges which simulate Analog gauges for various popular car models:

    http://www.dakotadigital.com/index.cfm/page/ptype=results/Category_ID=636/home_id=-1/mode=cat/cat636.htm [Broken]

    Pressure gauges are sometimes based on a mechanism known as the Bourdon tube:


    Electrical gauges can use the well-known d'Arsonval mechanism:


    In automobiles, engine oil pressure and temperature measurements are converted to an electrical signal, where the output voltage is proportional to the actual oil pressure or coolant temp. The device on the engine which does this conversion is referred to as a 'sender'.
    Last edited by a moderator: May 6, 2017
  9. Nov 14, 2013 #8


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    If anyone reads the Human Factors MIL Standard quoted by jhae2.718 above you'll notice that digital readouts are NOT the primary indicators used in aircraft. True, they give the exact quantity in question, but I guarantee you, in the heat of battle, a bar graph or analog indicator's relative position gives a pilot far more rapid "quick look" ability than reading a number. Engine temperature, or percent of full power can be glimpsed in milliseconds and, at the same time, the pilot can learn if they are within safe limits. Digital readouts of the same data are usually added in addition to the "Analog" types.
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