Need some help with an Airspeed Indicator

[Guest ksimmelink]

I am currently working on a new panel for the VFW-614 with all gauges representative of the operational planes when they flew.I am currently working on the Airspeed Gauge and I have everything working fine except the Mach meter. The VFW-614 had a rotating Mach dial which was exposed in a window on the left side of the gauge and a set of fixed pointers. I have tried to treat the dial as a needle and have tried to point the dial so that the correct mach number appears lined up with the pointers. So far I have been unable to do this. It may be that I don't understand how the mach number is formated. Anyone have any tips or suggestions?Kim Simmelink(Project Freeware, ret.)

[Guest Patrick_Waugh]

Kim,> The VFW-614 had a rotating Mach dial which was exposed in a window> on the left side of the gauge and a set of fixed pointers.This is the first "difference" that can mess you up. Normally, all "needles" have a 3 o'clock zero position, and rotate clockwise as they increase. If your "needle" is different (and here it is), then you will have to still work "as-if" the zero point is 3 o'clock, in terms of your non-linearity, but where your "needle" (or numbers) are painted, will be different (ie, in their correct positions). If your "needle" moves backwards, then your non-Linearity table will have to be reversed.> I have tried to treat the dial as a needle and have tried to> point the dial so that the correct mach number appears lined> up with the pointers.This is one method, and generally the preferred one, but you can also use a MAKE_MOVING, with a mask.>So far I have been unable to do this.So far, you have discovered how NOT to do it. =)> It may be that I don't understand how the mach number is> formated. Anyone have any tips or suggestions?One tip would be to ALWAYS tell us are you trying to make a C gauge, or an XML gauge, and to post any relevant code you are trying. We get tired of having to ask people. Never assume that your reader will know you and already know this.And, tell us what you tried, and in what way it failed to do what you wished.Good luck.

[Guest ksimmelink]

Thanks >One tip would be to ALWAYS tell us are you trying to make a C gauge, or an XML gauge, and to post any relevant code you are trying. We get tired of having to ask people. Never assume that your reader will know you and already know this.This is the first "difference" that can mess you up. Normally, all "needles" have a 3 o'clock zero position, and rotate clockwise as they increase. If your "needle" is different (and here it is), then you will have to still work "as-if" the zero point is 3 o'clock, in terms of your non-linearity, but where your "needle" (or numbers) are painted, will be different (ie, in their correct positions). If your "needle" moves backwards, then your non-Linearity table will have to be reversed.This is one method, and generally the preferred one, but you can also use a MAKE_MOVING, with a mask.So far, you have discovered how NOT to do it. =)

[n4gix 4,947]

>This is the first time I am asking for help, so thanks for the>tips.You still haven't said whether you're using XML or C code... ;)>Ok, there is one mistake, I was trying to line up the "needle">with the pointer, instead of lineing up the "0" setting with>the 3 o'clock position. You do bring up a good point in that>this scale has to rotate counter-clockwise as opposed to the>normal clockwise. So you are saying the non linearity table>has to be reversed (Highest setting to lowest??)That is precisely correct! ;)The "key" to deciding what type of element to use is based on movement:1. if the all movement is around a central axis, use a needle object2. if all movement is linear (up/down, side-to-side), use a shifted object

[Guest ksimmelink]

>You still haven't said whether you're using XML or C code... ;)The "key" to deciding what type of element to use is based on movement:1. if the all movement is around a central axis, use a needle object2. if all movement is linear (up/down, side-to-side), use a shifted object - - - (A:AIRSPEED MACH, mach) - - This has the corrected values for the scale figuring the "needle" is facing to the 3 o'clock position. But from what I have been told here I need to invert the Nonlinearity values (starting at the 1 values then work down to the 0 value) to get the scale to rotate counter clockwise?Also using the "Blackbox" utiltiy I read about in this forum, it would appear that the values that come from the (A:AIRSPEED MACH, mach)variable are actual mach numbers, so the values on the nonlinearity table should work?Thanks to all for the help so far!Kim Simmelink(Project Freeware, ret?)

[Guest ksimmelink]

Well, thanks to all the help I received, the mach gauge now starts out at the right point, and rotates in the correct direction. But the scale doesn't seem right, as it reads much higher than it should.Using the blackbox program (which read correctly)the string is displaying the following variable:%((A:AIRSPEED MACH,mach))%!10.2f!%(' A:AIRSPEED MACH')%!-36s!On my gauge it doesn't seem to respond until the blackbox and the default 737 gauge I have installed for testing read about .30mach. Then it starts moving much too rapidly until I get the following results:bb reading - .31 my gauge - .2bb reading - .33 my gauge - .3bb reading - .35 my gauge - .4bb reading - .36 my gauge - .5bb reading - .38 my gauge - .6bb reading - .39 my gauge - .7etc. on off the scale. I guess my question is does the %!10.2f!% after the variable in Blackboxes entry do some kind of conversion of the numbers?(A:AIRSPEED MACH, mach)