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1231  Using Arduino / Project Guidance / Re: Help!! I need more decimal places in float. on: April 06, 2013, 01:20:55 am
M_PI is defined in math.h. Good as anything, I suppose.

Code:
root@here:~# grep M_PI /usr/include/math.h
# define M_PI 3.14159265358979323846 /* pi */
# define M_PI_2 1.57079632679489661923 /* pi/2 */
# define M_PI_4 0.78539816339744830962 /* pi/4 */
# define M_PIl 3.1415926535897932384626433832795029L  /* pi */
# define M_PI_2l 1.5707963267948966192313216916397514L  /* pi/2 */
# define M_PI_4l 0.7853981633974483096156608458198757L  /* pi/4 */

1232  Community / Bar Sport / Re: Where did you lose your packages? Who's lost packages as buyer/seller? on: April 05, 2013, 03:46:54 pm
...kudzu in the SE of the USA, the cane toad in Australia...

But those were deliberately introduced. Also the multiflora rose (Rosa multiflora) or asian beetle (Harmonia axyridis). So sometimes it takes a whole government full of lugnuts.

1233  Using Arduino / Microcontrollers / Re: ATmega8 with external crystal on: April 05, 2013, 02:21:08 pm
Have you seen http://www.engbedded.com/fusecalc/?
1234  Using Arduino / Motors, Mechanics, and Power / Re: Max amp load on LiPo battery on: April 05, 2013, 10:42:50 am
You have done something wrong there,  because LiPo batteries have a huge current capacity.
Or might be a bad battery / bad battery protection circuit.
1235  Using Arduino / Project Guidance / Re: LASERs on: April 01, 2013, 12:00:06 pm
I'd suggest paying the extra dollar or two (or less?) and finding a module with a focusing lens. It doesn't appear that this one has one. Without the lens it's a bit of a luck that gives you a nice dot or a wide blob.

http://dx.com/p/2-5mw-focusable-dot-laser-module-4-pack-3v-46390
1236  Using Arduino / Project Guidance / Re: WindReader/balloon following device on: April 01, 2013, 11:54:59 am
OpenCV will work on the Pi; I saw one example where someone did face tracking at 5 frames/second which should be OK. It's pretty involved stuff but if you're just trying to identify a single-color balloon it shouldn't be that hard. There's also reacTIVision which is kinda plug and play.
1237  Community / Bar Sport / Re: What is the most challanging device that you have successfully soldered? on: March 31, 2013, 12:38:58 am
Mine was an LGA-14 (analog accelerometer). Bought them for fun because they were very cheap. Second try I managed to get it soldered on a home-etched board but it started smoking after about 10 minutes because of (I assume) some leftover flux under it.
1238  Topics / Robotics / Re: HS 311 only turns to the left on: March 28, 2013, 06:26:38 pm
You didn't mention the resistances in your voltage divider, but I suspect that they are too high to supply enough current (160ma no load requirement) to the servos. The linear regulator is a much much better choice.
1239  Using Arduino / Sensors / Re: Quadrotor prj using Angular Rate Sensors (ENC Series) --- Murata on: March 28, 2013, 11:51:49 am
No, you're going to need a board with both an accelerometer and gyro. The accelerometer is there so, via force of gravity, you can always get a zero point reference as to which direction is "down". If you need a zero point reference for yaw then you would also need a magnetometer.

1240  Topics / Robotics / Re: New to Arduino. Have To Complete A Robotic Challenge. Need Help? on: March 28, 2013, 01:59:59 am
So what have you done so far with your arduino?
...and where you given a robot platform or are you building from scratch?
1241  Topics / Robotics / Re: Advice For my university embeddded project radio control dog with animatronics on: March 28, 2013, 01:56:26 am
You want a 2.4GHz system; anything in the MHz range is antiquated.

If you're just looking for a straight up recommendation I'd point to the Turnigy 9x. You can find lots of reviews on this with a little searching; it's quite popular.
1242  Topics / Robotics / Re: HS 311 only turns to the left on: March 28, 2013, 01:45:35 am
i was using an e-flite 7.4 volt lipo with a voltage divider down to 4.8 volts

"A voltage divider" as in two resistors? Please explain.
1243  Using Arduino / Motors, Mechanics, and Power / Re: Non-blocking DC Motor? on: March 28, 2013, 01:40:04 am
See the BlinkWithoutDelay tutorial.
1244  Using Arduino / Sensors / Re: Quadrotor prj using Angular Rate Sensors (ENC Series) --- Murata on: March 28, 2013, 01:38:38 am
This is referred to as "gyro drift". I'm going to skip an explanation because I'd assuredly explain it poorly, but some Google searching will explain why you're seeing what you're seeing.

Also, the "50Hz" response means it takes 1/50th of a second to respond to the angular rate change -- it's the time it takes for the analog output voltage to match the angular rate of rotation. Or as another example, your fingers respond to heat at about 5Hz -- it takes you about a fifth of a second to realize what you're touching is hot smiley-wink
1245  Community / Bar Sport / Re: Idiot spammers on: March 28, 2013, 01:13:10 am
like millionaire death row prisoners who cant use a computer but are willing to fund opportunities if you just write them

Names? Numbers!?
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