This is where I got my formulae

from the site

Local, flat earth approximation
If you stay in the vicinity of a given fixed point (lat0,lon0), it may be a good enough approximation to consider the earth as "flat", and use a North, East, Down rectangular coordinate system with origin at the fixed point. If we call the changes in latitude and longitude dlat=lat-lat0, dlon=lon-lon0 (Here treating North and East as positive!), then

       distance_North=R1*dlat
       distance_East=R2*cos(lat0)*dlon

R1 and R2 are called the meridional radius of curvature and the radius of curvature in the prime vertical, respectively.

      R1=a(1-e^2)/(1-e^2*(sin(lat0))^2)^(3/2)
      R2=a/sqrt(1-e^2*(sin(lat0))^2)

a is the equatorial radius of the earth (=6378.137000km for WGS84), and e^2=f*(2-f) with the flattening f=1/298.257223563 for WGS84.

In the spherical model used elsewhere in the Formulary, R1=R2=R, the earth's radius. (using R=1 we get distances in radians, using R=60*180/pi distances are in nm.)

In the flat earth approximation, distances and bearings are given by the usual plane trigonometry formulae, i.e:

    distance = sqrt(distance_North^2 + distance_East^2)
    bearing to (lat,lon) = mod(atan2(distance_East, distance_North), 2*pi)
                        (= mod(atan2(cos(lat0)*dlon, dlat), 2*pi) in the spherical case)

These approximations fail in the vicinity of either pole and at large distances. The fractional errors are of order (distance/R)^2.

I took the Micromega examples and changed the great circle method to the one above.

Try this site

http://williams.best.vwh.net/

I'm using a Micromega FPU V3 with my GPS/Arduino, so none of my code will do you any good here.

Here is the link to the aviation formulae

http://williams.best.vwh.net/avform.htm

The big danger is static.
We were shown a video in high school where the demonstrator ran toluene through a horizontal glass tube, where the toluene ran out into a bucket he placed an earthed copper electrode near the stream.
Within a few minutes of the toluene flowing it went up as the charge jumped to the electrode.

As I said before, static is the danger.

A leaking fitting, at high pressure would get colder, it was static electricity that sparked.

Ok, you got Pythagoras down, it's time to grab a math teacher @school, tell them what you are doing, ask for some help.

It will be better for you in the long run, trust me.

Over short distances I've found the round off error from the Arduino's floating point libraries to be a problem.
Using simple trig over short distances, like around the block, seems to be more accurate.

SPI doesn't use an address, it uses CS.

Try having a 4 bit address bus between Arduinos, decode it with a 1 of 4, like a 74139 or 74155, you can make one from 7400 quad NAND gates.

Funny, a lot of people say that!

But hey!

I'm still here, still bilaterally symmetrical, 50 this year, I can still walk 50-60km in a day.

This is a tough one..

Maybe the second time I was electrocuted? Paramedic must have done a dance on my chest and one finger nail pretty much blown off.

Third time I was electrocuted, it was a big old lab strobe, sore chest again, but the lump on the back of my head where I hit the wall hurt.

Or having 350 V8 crash down on my hand when the "good quality" chain block broke, fire rescue took an hour to get me out of that engine bay.

The bovine that messed me up last year was pretty bad, 3 broken ribs, concussion, my normal 40 minute walk took about 6 hours.

And let's not forget the second time I was on fire!
When the Doc says "it's just superficial burns" it doesn't mean it aint gunna hurt for weeks...

Did someone allude to passing a kidney stone?
Been there, wasn't as bad as some boyz make it to be!


Fun times...

I am lovin' this "hydrogen hysteria"!

MUST show this thread to the guys that launch the radiosonde balloons at the weather bureau!

If you're not careful with black powder it can happen, mmm, fond memories of going to school with no eyebrows, eyelashes and frizzy hair!

Just so we know, CodingBadly, how did you loose your eyebrows with hydrogen?

For a "near space" project hydrogen is fine.
Here in Australia the Bureau of Meteorology release 2 weather balloons a day.
They fill them with hydrogen, because it's cheaper.
When you fill your balloon you need to do it fairly slowly, static is a BAD thing.

The Hindenburg gave hydrogen a bad rep!

I've filled quite a few balloons with hydrogen, all the times I've set myself on fire it was doing way dumber stuff.

You can make hydrogen from electrolysis or chemical reactions, like zinc in hydrochloric acid.
Most folks don't realise all the helium we have is all the helium we have!
It's why the USA could only fill the Los Agngeles OR the Akron, but never both!
There is quite a bit of controversy about the use of helium right now.
The USA has a stockpile, some scientists are cautioning that we are running out.

For MIG welding ARGSHIELD is way cheaper than helium, it's not as good, but you really only need helium if you are MIG welding aluminium.

Right now I'm going through all the rigmarole of getting CASA approval for a near space balloon.
The pricks are making me jump through more hoops than a dog and pony show!

When/if I finally get approval my balloon is going to be filled with hydrogen.
BOC gasses will sell you a cylinder full, it's no big deal.

The basic safety precautions are

- fill the balloon slowly
- don't wear synthetics
- don't smoke (hardest bit for me!)

Basically it's just a case of THINKING!

I got one of these
http://coridium.us/

In 8 days!!!

It's seems pretty cool so far.

Ok!
After more reading it looks like when I assigned pins I just happened to hit on a combination that didn't work!

<insert face palm>

anyway this board I put together with 3 '328's on it works well, using the easy transfer library with serial and now I2C, was a worthwhile experiment.

So far I've found that -

Servo library "disables" pulseIn and analogWrite
analogWrite "disables" tone

Are there any others?

My fix for the above is to use a separate '368 to control 2 servo's, another to control my 2 motor shields and one more to control 4 HC-SR04 ultrasonic range finders, all connected via serial to a Mega using the easy transfer library.
I may go to using I2C coz I've run out of serial ports.

Is there a better way?

I broke down and bought a lamp/magnifier that has 36 white LED's rather than a weird circular flouro tube.
It seems whiter than my last illuminated magnifier, maybe a tad brighter as well.

Certainly runs cooler than a flouro one!

Beginning to realise I need glasses!

Re: superconducting semiconductor.

http://en.wikipedia.org/wiki/Josephson_effect

It works a bit like a FET or valve.

Cray stopped research ages ago, but they principle has been applied in making standard voltage cells, SQID's and single electron transistors.

The frequency of the "gate" current vs the voltage across the junction is very linear.
Building an amplifier where the gain is controlled by gate frequency rather than voltage or current sounds really tricky.

Re: Toothache
Try clove oil or cinnamon stick, both are good topical anesthetics.

Re: rude/nasty comments about smoking weed
(insert comment the moderator won't like, something about erectile dysfunction, procreating with animals/one's self, general shortsightedness, believing everything the government says)

:-)