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I thought we had lots of leeway and just had to have TX/RX in a rough set ratio but had a few coils
that nulled fine but only got 2 - 3" air sensitivity...
that nulled fine but only got 2 - 3" air sensitivity...
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Silver Dollar,
> I've been making lots of coils lately too. How did you calculate these for a D shape?
I created my new D Coil Shape half with a Wire,
then bent it into a Circle and measured the Diameter,
then used one Of the Coil Calc Pages to Calculate the Turns for Inductance
- to match the original 27cm D Coil Inductance.
Seemed obvious to me.Comment
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Well I can certainly measure the length of one winding accurately
but bending it into a circle and measuring that with any accuracy
seems a bit difficult. I had hoped the calculator would have a button
to choose "D" shape somehow....Comment
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Actually, you can do a simple calculation:
D_Coil_Half_Circumference = (D_Coil_Diameter + PI * C_Coil_Diam / 2)
D_Coil_as_Circle_Diam = (D_Coil_Half_Circumf / PI)
Then just use D_Coil_as_Circ_Diam , in a Coil Calculator to get Inductance.
So, it seems that the D Coil Half as a Full Circle Diameter is about :
D_Coil_Half_as_Circ_Diam = (0.82 * D_Coil_Full_Diam)
So:
27cm DD Coil Diam => 22cm Diam as Full Circle
13.5cm DD Diam => 11cm Diam
21cm DD Diam => 17cm Diam
41cm DD Diam => 33.5cm Diam
... etcComment
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Wow thanks! That is very useful info!Comment
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For a DD coil it's simpler to take the average of the two diameters (vertical and horizontal) and use that in the coil calculator. The results are fairly accurate.Comment
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I want to add this link to a new Thread for using 7-SEGMENT LED Modules for the IDE
- in place of the 16x4 LCD :
http://www.geotech1.com/forums/showt...262#post191262
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Sorry thats VDI not IDE :
I want to add this link to a new Thread for using 7-SEGMENT LED Modules for the VDI
- in place of the 16x4 LCD :
http://www.geotech1.com/forums/showt...262#post191262
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Surely the battery life will suffer badly with the LEDs instead of the LCD?
Have you calculated the aproximate difference in current draw....of course if there is no alternative LCD available, that must be accepted....
Regards
AndyComment
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if the right led's are used it should use less.Comment
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Current consumption Comparison of LEDs to LCDs
Hardly. A pretty standard 4 line by 20 character display takes only around 3ma without the back lighting and a max of 60ma with.
You can barely light one modern LED with 3ma.....a minimum of 5ma to my mind.....but could be much more with cheaper/normal LEDs.
Though generally 16-18ma should be considered normal for a single average red/green/yellow/blue LED.
So during the night time (do you treasure hunt often in the dark? I don't!!), you can save a little on the battery power over an LCD possibly. But only then
Look here for a LCD example:- https://www.sparkfun.com/datasheets/LCD/SerLCD_V2_5.PDF
So you can light 12 modern/expensive high brightness, low current LEDs at the same time with the 60ma (though that can be reduced on most LCD displays at will to less than 30ma and still read the LCD on a dark night!)....
I have to admit that if you search at night most of the time, then the LEDs MAY give you a slight edge on battery life, but otherwise not.
You should have a good look around and plenty of thought, before going further with your design.....
I hope this helps further.
regards
AndyComment
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The LCD (any of the ones I have used, even the cheap Chinese ones,) remain VERY easy to read even in bright sunlight, a minor adjustment of the contrast may be required, dead easy to do, one trimmer/pot!!
Tke any device with an LCD display outside and simply look at the display.....
LEDs though would need to be cranked up to maximum intensity = maximum current!!!! Not good.....
I hope this helps further.
AndyComment
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Simply put, no. They would need to be cranked up to around 20ma per LED......
regards
AndyComment
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IMHO the VDI is meaningless if it doesn't do something with the sound quality. In bright sunlight every display is completely useless.Comment
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