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4936  Using Arduino / Project Guidance / Re: USB-USB File Transfer Module on: August 26, 2013, 10:10:46 am
Seems to me that the easiest way to obtain all the resources you're going to need to solve this problem is to use a computer rather than a microcontroller - it would be much easier to solve on an RPi or an embedded PC.
4937  Using Arduino / Project Guidance / Re: Medical Project_ sound activation of video software event on: August 26, 2013, 08:07:00 am
Do you actually need to generate moving graphics, or is it sufficient just to vary the brightness of a fixed image? It may be as simple as using PWM to vary the brightness of a lamp that is shining through a projection slide.

The Arduino side of this would be to recognise the sound of a heartbeat. Other people have created sound pressure level displays and graphical spectrum analysers so I assume that all the capabilities you need are possible, but I have no idea how difficult it would be to pick out the sound of a heartbeat from the background noise.
4938  Using Arduino / Project Guidance / Re: sending AT commands to receive sms on: August 26, 2013, 08:02:40 am
The output we are receiving seems indecipherable,it seems to be in ASCII?

I guess the output you posted comes from here:
               incomingByte =;

Because you're using print rather than write to output the received byte, what you're seeing is a decimal representation of the ascii character value. If you used write() instead, the ascii character would be written directly to the serial port so what you saw in the serial monitor would be exactly what was received.

However there are bigger problems with that sketch - you don't wait to receive a complete response before you send the next command, so you will end up throwing commands at the modem very quickly and not fully reading any of the responses. You need to think about when you want to send the next command.
4939  Using Arduino / Project Guidance / Re: Classic Obstacle Avoidance Robot - Please Help on: August 26, 2013, 07:12:43 am
Only problem is i have no idea how to adjust my code for this

IMO you don't adjust an existing 'bot to make it balance - you develop a 'bot that can balance, and then add on the navigation and sensing logic, which is likely to be complex in its own right but much less time-critical. This strikes me as combining two relatively advanced projects and I suggest you think of this as the long term goal that you work towards starting from some much simpler projects such as getting your proximity sensor working, developing a stable 2wd 'bot that you can move and steer, and then developing that into something that can avoid obstacles and navigate however you want. By the time you have developed all that for yourself you will be in a position to understand how difficult it will be to develop a balancing bot, and the hardware involved, and decide whether you're ready to tackle that yet.
4940  Using Arduino / Project Guidance / Re: Arduino controlled, C02 powered pellet gun on: August 26, 2013, 07:02:51 am
It would need to be extremely fragile to be able to be destroyed by something that was safe to use around humans - maybe use one of the construction techniques used for model aircraft, such as varnished tissue paper?

I suspect the best approach would be to have a fairly substantial main body that has all the working parts attached and is designed to be very slightly negatively buoyant, with an upper hull that is essentially just a low wall which just has to keep the water out and provides the tiny extra amount of bouyancy needed to keep the whole thing afloat. It could be sunk either by swamping it with near misses, or by hits near the water line which introduced leaks. It would be a bit like the ill-fated Duplex Drive tanks used during the Normandy landings - barely floating and easy to sink.
4941  Using Arduino / Programming Questions / Re: How to #INCLUDE my snippets and functions ( xxxx.ino) on: August 25, 2013, 07:30:34 pm
So, when I click on compile in the IDE, where is the current directory?

That's an interesting question. As I understand it, the IDE scrapes up all the source files it thinks are needed to compile your sketch, and dumps them all into a temporary directory. In practice that means all the source files in the sketch directory (with the ".ino" to ".cpp" munging that has already been mentioned), and all the source files in any library that is referenced by your code. A library is deemed referenced if a ".ino" file in the sketch directory #includes a header file that is in the library directory.

This scraping and munging and copying-into-temporary-directories is one of the things I like least about the Arduino development environment - it's poorly done and IMO misguided, and means that the actual behaviour of C++ code in an Arduino environment doesn't follow the conventional behaviour that you could expect to find in any other C++ environment.

It's because of these differences that I'm inclined to view the Arduino programming language as distinct from C++ although closely related - given that the Arduino documentation explicitly refers to the Arduino programming language, I suspect the Arduino developers had the same view.
4942  Using Arduino / Project Guidance / Re: help on basic programmation on: August 25, 2013, 07:16:44 pm
That's a slightly awkward question to answer, because it's a TVR and the boundary between production and aftermarket is slightly blurred for this manufacturer. The module was fitted by a dealer, which arguably makes it aftermarket fitment, but it was supplied by the same company that supplied the OEM alarm system and I believe it could have been fitted as OEM equipment if that had been specified. A quick google indicates that these devices are still widely available for household names such as Clifford, Meta, Toad in the UK and I don't know of any regulation or policy which would prevent them from getting UK type approval or complying with construction and use regs in the UK.
4943  Using Arduino / Project Guidance / Re: rc interupt/over-ride autonomous robot on: August 25, 2013, 05:20:40 pm
If you're looking for the override to originate in software (on your PC) and be executed in software (in your Arduino sketch) then it would IMO make more sense for the override to be sent over a digital communication link rather than over a conventional RC radio control channel. The RC approach would be quite easy to implement, but would not lend itself to a software front end.
4944  Using Arduino / Project Guidance / Re: help on basic programmation on: August 25, 2013, 04:06:34 pm
I've never seen an electric car window that doesn't require the operator to maintain a fairly substantial pressure on a switch for the whole time the window is closing.

I have a window lifter system that raises both windows when the alarm is switched on, no manual intervention required (or possible) after hitting the keyfob button to arm the alarm. I don't think this is particularly unusual.
4945  Using Arduino / Project Guidance / Re: New to arduino.. real time tracking project !! on: August 25, 2013, 03:48:30 pm
If you're doing this for the fun of it then there's no problem solving it with an Arduino. On the other hand, if you actually want to track the position of a person or people, wouldn't it be easier to use a smartphone to do it? There are already plenty of apps doing that sort of thing, and it would be easy enough to write your own if the existing ones don't do what you want.

You can certainly solve this problem with an Arduino instead, but it's quite a big and expensive thing to carry around and keep supplied with battery power.
4946  Using Arduino / Project Guidance / Re: Regulate temperature to shower by regulating hot water on: August 25, 2013, 03:45:25 pm
So where does a guy learn how to turn a servo one way for hotter, the other way for colder?

How is the Arduino going to know what temperature it is trying to achieve?

(Is this going to involve some sort of waterproof manually-operated control in the shower cubicle, by any chance?)
4947  Using Arduino / Project Guidance / Re: 4 serial connections on arduino uno on: August 25, 2013, 03:38:39 pm
I haven't used it myself, but the AltSoftSerial library seems to offer some advantages over the standard SoftwareSerial, if you need to use multiple ports concurrently.
4948  Using Arduino / Project Guidance / Re: Feasibility of F & P Motor @ 1 rp hour on: August 24, 2013, 09:59:44 am
How much torque does your drive mechanism need to provide? If you're only rotating 25 Kgs and assuming it's mounted somewhere close to the CoM, this doesn't feel like a project that will require any great complexity or cost, and multiple SSRs and big mains voltage motors repurposed to work as stepper motors feels like overkill to me. (I suspect this is what AmbiLobe was hinting at, too.)
4949  Using Arduino / Programming Questions / Re: SoftwareSerial port not available? on: August 24, 2013, 08:24:49 am
It looks to me as if you are enabling each SoftwareSerial port immediately before you try to read from it. I don't think that will work. SoftwareSerial doesn't receive data at the point you call listen() or available() or read(). The port is enabled when you call listen(), and will receive and buffer any data that arrives from then on; the available() and read() methods let you find out whether it has got any data buffered, and retrieve it. If you call listen() for a different SoftwareSerial then this one will stop receiving.

I think what you need is a state machine which listens to the peripheral serial and waits until it recognises a command, then executes the command. A command that requires a response from a sensor would be executed by enabling the sensor's serial port (and hence disabling the peripheral's port), sending the command to it and waiting until response was received or a timeout occurred. Then the peripheral's serial port would be enabled (hence disabling the sensor's serial port) and you are back to the starting point.

It is inherent in this architecture that only one serial port is enabled at a time and while the sketch is waiting for a response from a sensor, it will ignore any subsequent input from the peripheral.

I haven't used it, but I understand there's an alternative SoftwareSerial library and I seem to remember that one of the improvements is that it allows multiple ports to be enabled simultaneously. If you believe you need this capability, I suggest you have look for that and see whether it does what you need.
4950  Using Arduino / Programming Questions / Re: Trying to write code for Blood pressure monitor , Please give reveiw on: August 24, 2013, 08:11:19 am
Before trying to write something complex, write something simple. Your code is riddled with syntax and logical errors and I suggest you put it aside for now and look at, understand and run the example sketches that come with the IDE before you come back to it and have another go.
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