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121  Using Arduino / Sensors / Re: ADXL 335 Accelerometer for Leveling? on: December 06, 2012, 09:43:15 am
The calibration data should also taken after the sensor is mounted on the board or in the system.
122  Using Arduino / Sensors / Re: ADXL 335 Accelerometer for Leveling? on: December 04, 2012, 09:45:32 am
How have you verified 0.5° accuracy?  Have you calibrated the unit?


123  Using Arduino / Project Guidance / Re: 555 Timer in Arduino? on: November 30, 2012, 11:21:15 am
Using the Arduino to replace the 555 in a monostable mode would be a mistake unless you are going to use additional capabilities of the Arduino, extreme overkill.
124  Using Arduino / General Electronics / Entry Level Oscilloscopes from Tektronix on: November 30, 2012, 11:18:30 am
Tektronixhas come out with a new line of oscilloscopes aimed at the hobbyist and educational market here is the link

I recently needed to replace my old scope and I just a used Tek scope that has fewer features (no digital storage is one) and paid a little less for it than the new Tek 25MHz scope.  Although my scope is a 100 MHz I do not need more than 25 Mhz paying a little more I would have gotten a new scope with a  5 year guarantee.
125  Using Arduino / Sensors / Re: ADXL 335 Accelerometer for Leveling? on: November 29, 2012, 11:11:20 am

like Darkside40 I would like to hear from you to see if you used any filtering and what type you used.  Can you elaborate how you got 0.5° accuracy for the unwashed massses like myself.
126  Community / Gigs and Collaborations / Re: Wanted: Build desktop device that moves a camera at a precise speed [$$ for you] on: November 27, 2012, 11:16:56 am
I built a system that was supposed to take pictures using point and shoot cameras correlated in time to an easily detected event.  The system never met the time requirements, the images would sometimes be at the correct time but usually they were late by some non-deterministic time.  Troubleshooting in the lab with function generators and o-scopes showed the detection system and camera triggering pulse were all well behaved, the problem was in the point-and-shoot camera as it would take a while to make the exposure adjustments to make sure  that the picture looked good and this screwed my timing up.

Since then whenever I need to do similar I read for one of my Nikon DSLR as they do not have that delay, they can be told to take the image when the button is pressed.  Point-and-shoot cameras may have evolved such that they ojn be told to just take the image at the time you want it or the beautification fast enough so the time delay is not seen.  On that point you probably want to quantify how tight you want the spec take a picture for 1/10 of a second so when the acceptance test rolls around you do not get into an argument about close enough.
127  Using Arduino / Microcontrollers / Re: New kid on the block on: November 27, 2012, 10:53:40 am
It is easy to get into a contest of "Mine is bigger/better than yours!" and that depends on what you want to do and what biases, skills, etc. that you bring to the project.  The great thing is we are able to have  "Mine is bigger/better than yours!" contests because there are many options on the market, this is great because it allows people a better shot at finding something they work with and enjoy doing it.

Options is GOOD
128  Community / Products and Services / Re: What should our store carry? on: November 26, 2012, 07:57:45 pm
If you have a way to broadcast the Arduino stuff to the folks at Lockheed Sunnyvale you may get some strong interest from some of the guys their for their kids, and maybe a workshop or two aimed at all ages.

Oust some thoughts.
129  Using Arduino / Project Guidance / Re: Integrating a timer in a photoresistor sun-tracking system. on: November 19, 2012, 04:16:20 pm
Whenever I see someone using a tracking system based on sensors I always wonder why use a tracking device based on a sensor instead of just using the very precise available routine that will give you the location of the sun for your location based upon the time and location.  Maybe it is an exercise in sensors and a two dimensional optimization but who use it for a permanent application.

Maybe I am missing something and if I am wrong can someone explain the error in my thoughts.
130  Using Arduino / Sensors / Re: Animal detecting Sensors for Arduino? on: November 19, 2012, 10:09:45 am
There are image processing algorithms that can discriminate between bi- quadra-ped animals that would work for detecting animals within the field of view.  Processing video streams is not within the capabilities of pre DUE Arduinos and DUE may need some kinks worked out of it as many first issue systems do.
131  Community / Gigs and Collaborations / Re: Looking for someone to write code for dslr video autofocus/ remote focus - NYC. on: November 11, 2012, 05:30:36 pm
Yes it should have read impossible.
132  Community / Gigs and Collaborations / Re: Looking for someone to write code for dslr video autofocus/ remote focus - NYC. on: November 11, 2012, 10:26:40 am
Do you intend to use the sonar unit to measure the distance between the object and the focal plane of the camera and set the focus based simply on distance or are you thinking of using image processing techniques to determine when the image is in focus?  Both methods are possible, but the latter is practicably possible with the Arduino due to processing power, memory and bus, to name a few.  Reading the sonar and adjusting the foucus using a simple look up table is within the capabilities of Arduino.

Using image processing techniques to perform the autofocus is possible with the processor on the Due, I am not certain that the Due hardware/software is stable enough to engage that large a project on.
133  Using Arduino / Sensors / Re: FREESCALE MPL3115A2 PRESSURE SENSOR on: November 09, 2012, 10:17:04 am
Without a schematic and your modified source we are going to have difficulty helping you.
134  Using Arduino / Project Guidance / Re: Project - Arduino to know the difference between 2 objects on: November 09, 2012, 10:05:44 am
If I was looking to do this in volume I would try to find a material that was opaque in the visible yet transparent in the IR and another material that was opaque in the IR and transparent in the visible and arrange matching photodiodes/transistors.  When the objects were brought in they would block the photodiode from its inband light and you could read the values on the PD's to determine what was in front of it.

I say in volume as it may be expensive to set up a run initially for the "water" and "food" objects.
135  Using Arduino / Project Guidance / Re: GPS accurate to cm's? on: November 08, 2012, 04:45:48 pm
You might want to do a SLOC count as a rough metric of whether the processor has enough memory to handle the size of the executable.  I do not have the time to do this and if I were to build a system like this I would port it to a processor that has enough power to do near real time updates.
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