IDX-PRO+VDI

[der_fisherman]

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.
Andy

[Koala]

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

Andy

Would LEDs work better in bright sun light?

[der_fisherman]

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

Andy

[sinclairuser]

if the right led's are used it should use less.

[der_fisherman]

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
Andy

[ampirate]

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/showthread.php?21584-VDI-by-7-Segment-LEDs-for-IDX-PRO&p=191262#post191262

[ampirate]

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/showthread.php?21584-VDI-by-7-Segment-LEDs-for-IDX-PRO&p=191262#post191262

[Qiaozhi]

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.

[Silver Dollar]

Wow thanks! That is very useful info!

[ampirate]

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
... etc

[Silver Dollar]

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....

[ampirate]

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.

[Silver Dollar]

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...

[golfnut]

Im saying dont beat yourselves up using umpteen decimal places, close is good.

With the IDX, I made the Tx 12kHx and the phase shifters for clocking the Disc and GEB channels worked well. I had the Rx tank about 8kHz.

As long as the Rx is about 75% of the Tx you will have some sensitivity. If you have staggering Air sens - it is likely the Rx taank is tuned too close to the Tx. And will be twitchy over land.

I think quiazhis coil cal app works well enough and is well regarded and proven so will give good first time results. People often make lots of versions and say oh that one was bad so I made another... There is no bad coils, its just how you phase them up and tune the phasing for ferrite reject, good sens, average null at preamp out.

If you have dry sand or clear earth low mineral, you can move the ~Rx tune colser to Tx and will give extra depth without the twitchy.

If you have meadow or wet minelaised clay you will benefit from having the Tx / Rx split up a bit more. Reduces sens a bit, but wont false about..

These are the trade offs I work to.

[Gwil]

For non-circular coils, find the area enclosed by the coil (one way is to draw it full size on graph paper and count the squares). Then calculate the size of the circular coil that encloses the same area, and find its inductance. I've found, from measurement, that gives good results.