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1  Using Arduino / Project Guidance / Re: Building of flight controller on: June 25, 2014, 03:57:40 pm
I have a lot of friends who have used the MultiWii and MultiWii Pro flight controller boards.  They are Arduino based and are about as cheap as flight controllers come.  There are definitely much better flight controllers out there with much better sensors, but they are much more expensive.  Even the APM (ArduPilot Mega) is quite expensive for an Arduino based board.

I have looked at the MultiWii code and it is gigantic (For Arduino Code).  I think it had upwards of 20 different source code files many of which were thousands of lines long.  Writing it yourself would be exceedingly hard for all but the most experienced navigation and control theory programmers.

Having worked on a quad myself, I would plan to spend at least a few months of hard work on simply assembling and tweaking the quad-copter before you will have it flying well.  This would include about 3 crashes that necessitate replacing motors, and frame components and dozens of broken blades.  In all, you should be prepared to spend at least a few hundred dollars on this endeavor. 

In all, it is certainly doable (and fun), but you should know what your in for.
2  Using Arduino / Project Guidance / Re: Switching USB on and off on: June 12, 2014, 09:45:01 pm
What would happen if you simply cut the 5V line?  It would certainly never draw power from USB, but the data lines would still be there. 

The question I can't answer myself is if the Arduino or computer would ignore the data in the absence of the 5V line.
3  Using Arduino / Project Guidance / Re: Anyone ever try this? on: June 12, 2014, 09:40:43 pm
I'm surprised no one has mentioned the product Sparkfun stocks that cable for.  It seems quite applicable...
4  Using Arduino / Project Guidance / Re: i need help for my graduation project on: June 12, 2014, 09:36:08 pm

I just completed my own BSE electrical engineering senior design project, and I will admit that I did ask for some help here, but there is a BIG difference between what I asked and what the OP did.

This community (and your professor) is typically happy to answer questions like:
1.  I tried X, Y, and Z but I still can't get my code to upload, any ideas?
2.  Am I biasing this transistor correctly?
3.  Where might I find a source for X component?
4. Is this datasheet actually correct?

But if you expect us to do all of your project for you, you deserve to fail.  I spent well over 400 hours on my project.  If I did have the time, money, and ambition to do your entire project, write a good report, and complete the other requirements I certainly wouldn't turn all my work over to you so you could take all the credit! 

As a side note, I do have to disagree with Jack.  I have seen a few electrical projects at my College that seemed feasible to start with, but as the team developed their solution they found that due to the limits of their budget, time, or technology their project would not be feasible.  They actually did quite well as they were still able to put together something they could show worked to a degree and in their report they gave a detailed workup of why what they tried to do actually wasn't possible. 

In short: If you have a question ask your professor.  If they don't know the answer, go ahead and ask here, but if they tell you to find out yourself, get to work.
5  Using Arduino / Project Guidance / Re: ARduino for Stadiums ? on: June 12, 2014, 09:02:22 pm
I love Arduino as much as most of us here, but I agree with Jack.  If it were me I would find a switch that could switch the main voltages for the light and siren.  A double pole switch would keep both of these separate and connect both when the switch was triggered.  Multiple switches could be easily wired in parallel and the system would use no power when off at all!

The only downside I see with this way is that if the switch was re-closed the alarm and lights would turn off.  To prevent this you could use a switch to turn on a relay wired with some hysteresis such that once the switch is thrown the circuit will turn on and the relay  would stay on by itself until power was disconnected from the system.  If you want I (and probably other here as well) can post a schematic of this setup.  Even with the relay and hysteresis it would still use no power in standby.
6  Using Arduino / Project Guidance / Re: Control a relay on: May 26, 2014, 08:15:37 am
For every additional battery you add you will need two more poles of relay.  So if you have SPDT relays this would be another two relays.  One relay pole will disconnect the ground of the battery while the other pole will move the positive wire from the charger's positive output to the previous cells - side.

I don't quite understand what you are getting at with the coms pin?
7  Using Arduino / Project Guidance / Re: Need some technical informations and advices. on: May 24, 2014, 07:30:23 am
At least in the US they chain the traffic counters to the telephone poles and build them in boxes that make them look very industrial and hardly worth stealing. 

You should be able to measure the current consumption of your system with just a multimeter and the wall adapter power supply.  If you get a separate barrel jack like this one you can then wire the power to the Arduino by bringing ground to the ground pin and the V+ to the Vin pin.  You can then place your meter in current mode in line with one of those two wires and you have the current. 

If you don't have a multimeter yet, now is the time to get one.  I couldn't imagine doing a little project let alone a master's thesis without one.  Even a $20.00 hardware store meter would give you the information you need and help you out in many other ways as well. 
8  Using Arduino / Project Guidance / Re: Any company/service that can print and assemble a circuit board for me? on: May 23, 2014, 04:01:21 pm
Yes these companies exist, but there will be some potential issues.

1.  Quantity:  If you wanted say 20,000 boards there would be any number of companies that could do this, but if you want 1 at a reasonable price things get harder.

2.  Technology:  Are we talking simple through-hole components, basic SMD, or some evil BGA stuff.

The only place that comes to mind is that Seed Studios PCBA service, but it limits you to their set of OPL components seen here.
9  Community / Bar Sport / Re: What Faggot means in the UK on: May 23, 2014, 03:49:59 pm
To the musicians here it clearly refers to a Bassoon.

I remember a good deal of giggling in my high school orchestra when we played our first Italian piece.
10  Using Arduino / Project Guidance / Re: Control a relay on: May 23, 2014, 03:24:55 pm
Yes you should be able to do that.  I didn't fully see what that switch was doing, but in general you can replace a switch with a relay.  If you need to have a 3PDT relay you could certainly find one on Digikey, Mouser, etc.  You could also use 3 SPDT relays, but you would want to make sure they all switch together. 

Depending on the relay, you should be able to drive it with the motor shield or any other motor driver.  You would connect one side of the coil to ground and the other side to an output of the motor driver shield.  Now whenever that output goes high the relay will switch on.  You can control the relay by commanding the corresponding 'motor' to move or stop. 

If you are only driving the relays you could also just use a simple MOSFET to control the relay coil as an alternative to the motor shield.  If you have multiple relays you could likely stack the coils and so long as you have the voltage to drive the 2-3 coils you could control them with one output and guarantee they switch together.
11  Using Arduino / Project Guidance / Re: Arduino to Processing on: May 23, 2014, 03:13:02 pm
I am no Processing expert, but let's take a look at the code you posted.

This is the critical line:
String[] input = trim(split(myPort.readString(), '\t'));

In this line you start by reading in a line of input from the serial port with

Then you split this into a list of strings with the split method.  As you gave it the parameter '\t' you will break the string apart on tabs.
split(myPort.readString(), '\t')

Now you have a list of the line of input split apart into different tab separated parts, but the extra tabs are still there, so trim gets rid of the extra whitespace.  This is assigned to an array of Strings to store each of the received values.

Now if you had the serial input that you posted here, you would have read in one entire line into the string array input.  To get the value out you could use something like this.
//This code is untested but should be close
float firstValue = float(input[0]);
float secondValue = float(input[1]);
12  Using Arduino / Project Guidance / Re: Auxiliary power plug port phenomenon on: May 21, 2014, 07:52:57 pm
I don't know what is happening with the 9V plug, but on start-up all of the pins go to their default of an Input pin.  It could also be the case that the built-in pull up resistors are activated in this status, but I don't know for sure.  Try adding something along the lines of a 5K pull-down resistor to the output pin you care about and see if it solves the issue. 
13  Using Arduino / Project Guidance / Re: Uploading sketch's over bluetooth?... on: May 21, 2014, 07:39:04 pm
It may be possible depending on the given module.  Some are made specifically to support this and some kind of support this. 

That said from personal experience this can be a very difficult issue, so I would try to buy a module that was built to do this or avoid uploading code over Bluetooth entirely. 
14  Using Arduino / Project Guidance / Re: Arduino to Processing on: May 21, 2014, 07:20:42 pm
You shouldn't have to change your Arduino code at all.  You can just use the Processing Serial library: to receive and parse your data.  From there I would address any questions to the Processing forums where you are much more likely to find someone with the needed experience.
15  Using Arduino / Project Guidance / Re: Help please Conversion from ascii to binary on: May 21, 2014, 07:07:07 pm
Yes, please clarify your needs exactly.  There are fairly easy ways to do conversions from and to bytes, integers, strings, and chars.  The problem is there is a lot of them, so we need to know what you are doing.

1.  Where does the data originate (Your PC's Serial Monitor, Another PC Application, The Arduino)?
2.  In what form is that data?
3.  Where is the data going?
4.  What form do you want the data in once it is received?
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