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31  Using Arduino / Project Guidance / Re: Arduino servo control for large number of servos on: August 06, 2014, 05:28:34 am
It's a pita just to install opencv, and I'm not the only one who is confounded by it.

What platform are you trying to install it on?
32  Using Arduino / Project Guidance / Re: getting data from html to arduino on: August 06, 2014, 05:24:54 am
I need to get data from the webserver html to the arduino, and this data is an input in the html

Is the Arduino acting as a web server, or is the web server some other machine?
33  Using Arduino / Project Guidance / Re: Quadcopter: Question about PID. on: August 06, 2014, 05:21:55 am
I haven't found any.

Then you can't have looked very hard, because DIY UAVs are extremely popular at the moment and there are plenty of open source autopilots about for them. What search terms have you tried?
34  Using Arduino / Project Guidance / Re: Robot? on: August 06, 2014, 05:18:52 am
Very very very very new to Arduino

If I ... decided to produce a saleable product

Put that thought out of your head. You're nowhere near selling an Arduino-based product, and by the time you ever got to the position of having something fit to sell then the cost of a few standard Arduino components bought along the way would be irrelevant. Just buy what you need to solve the problems you want to solve.
35  Using Arduino / Project Guidance / Re: Robot arm project guidance wanted (transistors) on: August 06, 2014, 05:13:17 am
I just bought a set of jumper wires, a 4 pin connector, an AD-01 breadboard, I've done a little experimenting and I am still not sure how to use them, I will post more information shortly but I can really do with advice on how to use these transistors.

In my opinion you're wasting your time (and ours) unless you find out what voltage and current you're trying to control. You need to get a meter and measure the characteristics of the circuit you're trying to interface to. Without that information we have no way of knowing whether you need transistors, or whether the ones you have got would be suitable. It's been said before, but worth repeating: if the circuit needs less than 40mA and 5V to operate then the Arduino could drive that directly.

You need to understand the electrical characteristics of the circuit you're interfacing with before you can design the circuit to interface to it. This is fundamental.
36  Using Arduino / Project Guidance / Re: High accuracy servo, various component selection on: August 05, 2014, 11:49:39 am
Is the servo going to be driving your table directly? How big/heavy is this thing and what sort of loads will it have on it? I'm struggling to visualise the mechanical side, and without understanding that it's hard to advise how to drive it.
37  Using Arduino / Programming Questions / Re: Problem with using accelstepper library on: August 05, 2014, 07:20:18 am
I know how to make it move but I dont know how to make it stop. it just keeps going on and on, can someone help me make it stop?

Instead of telling the stepper to move by a given offset by move() , tell it to move to a specified position by moveTo(). Then it will stop itself.
38  Using Arduino / Project Guidance / Re: Having Arduino and Gobetwino wait for eachother to continue on: August 05, 2014, 07:10:36 am
Is the length of time taken per measurement reasonably consistent and predictable? I'm wondering whether you could just take measurements on a timed basis. If so, that would make things a lot simpler.

Otherwise, does the result of the measurement appear in the spreadsheet, and is it important to you that it is available there? If so your best option would be to modify the template to include a VB fragment that wrote to the Arduino COM port when each measurement was complete, but if you don't need to stick to the Excel approach it might be possible to find out how the spreadsheet communicates with the sensor (I guess it's probably using a virtual serial port) and write your own client that can get / save the data as required and control the Arduino too.
39  Using Arduino / Project Guidance / Re: Quadcopter: Question about PID. on: August 05, 2014, 06:48:32 am
I have a doubt with PID control

If you are intending to write your own controller, I recommend that you don't. It's extremely difficult to do, and will likely take years of effort with numerous failures along the way. There are various open source controllers you can use. Simply taking somebody else's controller and making it work in your project will be challenging for a novice.
40  Using Arduino / Project Guidance / Re: Measuring distance with RF on: August 05, 2014, 06:45:36 am
Averaging over 256 ping's would increase this value down to ~1 m or so.

Only if you have the appropriate amount of random noise in your measurements.
41  Using Arduino / Project Guidance / Re: I need to create a tensioning system for a prosthetic device. on: August 05, 2014, 06:42:30 am
I am looking to create a way to control a small motor in a device that is worn under clothing.

Start by picking the motor/servo that you want to control. A servo will be much easier to control than a DC motor since it contains all the related driver electronics and gives you direct positional control (or direct speed control, with modification).
42  Using Arduino / Project Guidance / Re: Arduino servo control for large number of servos on: August 05, 2014, 06:39:18 am
For question 1, I suggest you create an application using OpenCV on a computer. There are various language bindings for OpenCV and C++ is supported, so that would be a sensible choice IMO. To convert an incoming video stream to gray scale and read the brightness of each pixel will take a couple of dozen lines of code.

For question 2, I suggest you send the pixel data over the USB serial connection to the Arduino. You will need to choose a message format for the data. Given the quantity and rate that you're sending I suggest using a binary format such as one byte per pixel giving the corresponding servo position, with some start-of-message and end-of-message markers. Arduino code to read a stream of servo positions and adjust each servo to its new position would be relatively simple. If you want the Arduino to apply any extra logic, such as interpolating or smoothing the position values, then you need to work out how much memory and processing speed that is going to require and choose a platform with sufficient resources.

For question 3, what is a stepped servo? Do you mean a stepper motor?
43  Using Arduino / Project Guidance / Re: High accuracy servo, various component selection on: August 05, 2014, 06:29:57 am
if ... this servo was inaccurate, it could be life threatening. Would a secondary feedback system be necessary for this?

Absolutely essential - and the whole system would need to be designed so that all conceivable failure modes failed to a safe condition. Without that level of protection, the nominal repeatability / accuracy of the servo is the least of your problems since you have to assume that eventually one or more things will go wrong (mechanical wear, electronic failure, firmware bug, wiring fault, user error etc) so that the servo position will go arbitrarily wrong.

There's nothing to stop you from putting together a proof of concept, and using it yourself if you want, but before you sell a product which has safety implications you have a massive amount of work to do and you should not be relying on advice from a public forum about how to do it - you would need expert qualified advice with appropriate indemnities.
44  Using Arduino / Project Guidance / Re: changing file name when saving file help?? on: August 05, 2014, 06:21:10 am
You need to design the web page so that it presents a control that the user can use to request the save. For example you could include a form with a submit button, or just use a hyperlink.

You need to design your web server so that it recognises the HTTP request corresponding to the save request. The most obvious way to do that is to have the submitted URL path specify the save request.

Your sketch needs to determine the file name to save to using whatever algorithm you want. One algorithm would be to generate a name which included a sequence number and just keep incrementing the sequence number until you find a name for which there is no existing file.

You need to write the data to the named file.
45  Using Arduino / Project Guidance / Re: Guidance on reading from .TXT file on: August 04, 2014, 11:00:55 am
As Grumpy_Mike says, to read the file directly it needs to be stored on a device that the Arduino can access.

It's possible to read a text file stored on a PC that the Arduino has a USB connection to but that requires some software on the PC to read the file and send it to the Arduino. Your options for that depend on what OS the PC is running. If it's Windows, you can use Gobetwino to read the file.
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