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1  Using Arduino / Networking, Protocols, and Devices / Advice appreciated for wireless time syncing without internet based NTP servers on: August 07, 2014, 08:10:52 am
Case:
Guy on laptop playing music and controlling some visuals on a separate UVO (Undefined Visual Object). He works with a typical piece of software which is capable of outputting OSC. Maybe I can get it to do more like using Bluetooth but, unsure for now. The environments can be quite hostile regarding WiFi noise (event locations with their own blaring repeaters, etc). I can also not guarantee internet, and don't want to be dependant.

My primary solution was using WiFi. Laptop has wifi, easy to integrate protocols and so on. But I was getting trouble with a highly fluctuating round trip time. For syncing music with visual, this sucks. The object is using a WiFly module from Roving Networks in soft AP mode.

Questions:
What would be a nice solution for wireless time syncing a laptop with an Arduino, without the use of internet/NTP?

Sub-questions:
What is the best use of the WiFly module? Would using a separate router as AP make a huge difference?


Any help is appreciated!
2  Using Arduino / Project Guidance / Re: LiPo battery and safe operation (exhaustion) on: February 07, 2012, 10:15:12 am
@peter I already have some arduino's, I'd rather not buy more. Of course its always good to look into innovative designs

@retrolefty I would much more prefer if I could dismiss the arduino in protecting my battery, as in, not using the arduino for sensing and controlling. My battery has no such circuitry for protection. This is mainly the reason I'm looking for solutions.

Thanks for your replies, I'll try shopping for other batteries that include protection for min. max. voltage.
3  Using Arduino / Project Guidance / LiPo battery and safe operation (exhaustion) on: February 07, 2012, 08:54:50 am
So, I have a 11.1V LiPo battery, a small circuit with a LED (LiPo Saver they call it) that tells me when I reached its limits (low voltage <3V per cell). Now, I'd like to run the complete project (arduino, motors etc.) via some sort of circuit that will only work if I have enough power in the battery.

What I was thinking (discard if bullshit): I take an optocoupler with triac (MOC3041 or something) that I'll try to run via a voltage divider that will deliver the minimum amount (1.3V) at the maximum (11.1V) voltage (or a better equation) e.g. if the voltage of the battery drops, the voltage divider cannot supply enough voltage the drive the LED on the optocoupler...
Or, I use this LiPo saver somewhere in between with a transistor npn in parallel with its LED... ...something (you have probably guessed my knowledge level at this point...)

Better suggestions are MORE than welcome. My main question comes down to: "What is the most save way of protecting my LiPo battery from undercharge?"
I prefer to shield the stuff as much as possible from each other.

Thanks in advance,
Aduen
4  Using Arduino / Sensors / Re: Capacitive touch screen on: January 25, 2012, 12:48:43 pm
you will have a better day connecting the complete ipod to an arduino and not disecting a SMD circuit for your touch screen hardware (if thats what you would be thinking about)

They have some stuff for it, never used it though.
http://scuola.arduino.cc/en/content/arduino-comunication-iphone-using-podbreakout-v15

You could also go for the preferred option and use an Android device
http://arduino.cc/en/Main/ArduinoBoardADK

Good luck
5  Using Arduino / Sensors / Hygrosens Doppler effect sensor for velocity measurment on: January 23, 2012, 05:52:00 pm
Most of the topics I found (dating before 2011) about this one sensor start of like this:

Hey, I have this sensor from Hygrosens:
http://shop.hygrosens.com/out/media/radar_dbe.pdf

Does anyone have any experience with this module...

So hereby.

I have it hooked up to the arduino (nothing to difficult), open-collector works fine with an interrupt.

I've also did some arduino-oscilloscoping and found that the line-in of the pot gives out some more data if used raw in an analog pin (did some multimetering to, all neatly within arduino capabilities). It gives a frequency and a voltage. The frequency should provide some velocity measurment and the voltage the amount of waves returned (e.g. size of object). None what so-ever documented in exact details (Hygrosens is enquired).

I've tried sampling the analog pin with pulseIn() but got the same result every sample. I would agree that it means I should only have to sample one time but, I'd like to know if anyone else tried hooking it up like this...

I've also not tested the velocity yet, "whacking" at it didn't deliver anything beyond 23Km/h (wouldnt know if thats correct  smiley-confuse ). Knowing
Quote
"...signal originating at the mixer output is proportional to the speed: 44 Hz corresponding to a movement speed of approx. 1 km/h."

With no more interesting code:

Code:
//lowest F 5Hz
unsigned long f = pulseIn(A0, HIGH, 200000);

//44Hz == 1Km/h
f = (1000000/f);
float kmh = f/44.0;

If I find a way of more precisly measuring the outcomes, I will let it know in this thread. For now, anyone, experiences...?
6  Development / Suggestions for the Arduino Project / Re: Delegate system for member function pointers on: January 19, 2012, 11:03:23 am
I've made it into a small library that you can unpack in the Arduino folder, I made it in 022, not 1.0. Have not tested it in 1.0 to (don't think it will work in the new one yet cause of the class differences) something for later on.

So, just unpack in the libraries folder of the arduino install, start/restart arduino software and you can look for it in the examples and libraries menu.

I did not made the delegate system API friendly yet but, its not that difficult as you will see in my code (kept it small). If it starts interesting more people I'll consider making the Delegate system more friendly.

http://img.aduen.nl/TimerLib.rar

7  Development / Suggestions for the Arduino Project / Re: Delegate system for member function pointers on: January 18, 2012, 01:26:04 pm
I am using it myself right now, so a fully working example wouldnt be a problem. I've also rewrote the SimpleTimer lib from
Code:
Author: mromani@ottotecnica.com
using this system and some other advantages.

I'll make it a arduino lib with an example attached and post it for download in this thread. I'll try to get this done before the weekend.

@westfw: its for member function pointers, a simple function pointer wouldnt need a delegate system ofcourse. Although my current setup does all the magic in the background so you could easily throw in a simple function pointer or get more freaky and use a delegate for a member function pointer like so:

Code:
//no class
void simple_function(){
//do something
}

timerlib.setTimer(30000, simple_function, 0);

//within another class
delegate d = MakeDelegate(this, &BigClass::someFunction);

timerlib.setTimer(30000, d, 0);

With no changes in the timerlib object. This is ussually a hackle because non-member functions dont get a this operator, where member functions do get these. If your this operator gets screwed the called function has no clue whats going on in its own class/object.

But, I'll get back on this thread with some descent examples so its all getting a little clearer.
8  Development / Suggestions for the Arduino Project / Delegate system for member function pointers on: January 12, 2012, 04:48:55 am
Because I like programming in objects/classes, I got myself in a situation to use timers and callbacks. This is generally an issue in c++ (member function pointers)

I found this Delegate system that covers a whole lot (too much for standard Arduino programming)
http://www.codeproject.com/KB/cpp/FastDelegate.aspx

I works very nice, changed the SimpleTimer lib (Author: mromani@ottotecnica.com) to be used with this Delegate system.

What I was thinking, since Arduino programming is getting more and more professional on one-side, having a standard low-footprint Delegate system could be a nice addition.

I already got it working and the extra memory needed is very little, the guy who made it states that in most cases it would only compile to two lines of assembly. What still needs to be done is cutting it up (i guess 80% of the code could be discarded since Arduino uses a single compiler) and making it integegrate easy (without API breaks)

this is my compile output for a small program with this Delegate system:

With FastDelegate:

Code:
AVR Memory Usage
----------------
Device: atmega2560
 
Program:   17178 bytes (6.6% Full)
(.text + .data + .bootloader)
 
Data:       1292 bytes (15.8% Full)
(.data + .bss + .noinit)
 
 
Finished building: sizedummy

Without FastDelegate:

Code:
AVR Memory Usage
----------------
Device: atmega2560

Program:   17030 bytes (6.5% Full)
(.text + .data + .bootloader)

Data:       1292 bytes (15.8% Full)
(.data + .bss + .noinit)


Finished building: sizedummy

Code as in test (working)

typedef
Code:
typedef FastDelegate0<> FuncDelegate;


 Code in robot class:
Code:
void Robot::test(){
    FuncDelegate f_delegate;
    f_delegate = MakeDelegate(this, &Robot::halt);
 
    timer.setTimerDelg(1, f_delegate, 1);
}
 
void Robot::halt() {
    Serial.println("TEST");
}


 Code in SimpleTimer class:
Code:
int SimpleTimer::setTimerDelg(long d, FuncDelegate f, int n){
    f();
}


Arduino prints TEST in the console


It all worked nice and fast, if it is not something to be used, mods may delete this post.
9  Using Arduino / Installation & Troubleshooting / Re: Uploading Problem with MEGA 2560 and MAC OSX on: January 12, 2012, 04:30:52 am
You are not the only one with this problem its the new bootloader. It does not reset the board before uploading.

I found 2 hacks, which are both quite nasty ones:
triggering the old bootloader (for the reset), then the new one (for uploading)
connecting the solderpads called RESET_EN (dont do this unless you are completly familiar with the hardware, I am not)

http://arduino.cc/forum/index.php/topic,86518.0.html
http://arduino.cc/forum/index.php/topic,86088.0.html
10  Using Arduino / Installation & Troubleshooting / Re: Cannot upload sketches with Arduino 1.0 on: January 12, 2012, 04:23:19 am
I've heard someone having succes by connecting the solderpads on the Arduino called RESET_EN, they are just above the Vin pin. Although I don't have more details about this. Maybe someone with better knowledge of the board could comment on this.

I work in Eclipse and found out that they use a completely different bootloader for the 2560 (stk500v2), this resulting in the board not resetting before uploading. I just hit the reset button before uploading, like the old days smiley
11  Using Arduino / Motors, Mechanics, and Power / Re: Measuring LiFe battery pack voltage with Arduino on: February 24, 2011, 01:13:13 pm
Ah, sweet dudes thanks! I'll will also take the extra 22k resistor recommendation just to be sure (not having a 5.1 zener diode lying around  smiley-wink ).

Thanks everybody!

This is what it's all for:

...soon it will be rolling around
12  Using Arduino / Motors, Mechanics, and Power / Measuring LiFe battery pack voltage with Arduino on: February 24, 2011, 06:30:52 am
Hey,

I was wondering what the possibilities are of measuring the voltage of a LiFe battery pack of 13.2V. I know I can divide the voltage so its 5V at 13.2V and measure the 5V with the analogue input of the Arduino to see the drop.

Now what I am worried about (this is where my limited electronics knowledge gets me), is it safe. I am afraid that I might feed the Arduino boards analogue input a massive current and completely blow the life out of it. Maybe my previous stated idea is wrong from the start and there is a safe solution.

The battery feeds a big motor, a big servo some sensors and the Arduino board. The battery pack is from Graupner (13.2V 2000mAh) 4C LiFe.
For these kind of batteries it is not recommended to completely discharge them, that's why I want to cut it's supply before this happens.

I you guys can help me, (maybe there is a thread already about this topic but, I was fighting the new search engine and I lost)
13  Forum 2005-2010 (read only) / Syntax & Programs / Re: VB.NET serial communication on: December 18, 2007, 02:39:27 pm
Nice thanks,
the link is indeed very helpful for me.
[some.thumbs.up.figure.thingie.icon]

ciao
14  Forum 2005-2010 (read only) / Syntax & Programs / Re: VB.NET serial communication on: December 18, 2007, 01:50:41 pm
Hey,
I see I am not the only one who is trying it's luck with VB. I've made a program that feeds a MySql database with sensoric input from the Arduino. The program searches the arduino and when found it keeps listining for input from the arduino. When senoric data comes in it's directly pushed to the database.

The only thing I am not familiar with is the use of char variables for string makeup. I am trying to construct  a string of different char variables but I am missing out an something I guess.

It needs to be a comma seperated string just like above here :smiley is explained.

can someone help me with this piece of code
15  Forum 2005-2010 (read only) / Troubleshooting / Re: analogWrite(3, 255) == digitalWrite(3, HIGH)?? on: June 18, 2010, 08:15:59 am
cool thanks for that explanation, saved the data for later use smiley-wink

Well, on topic. Eventually found out that I had an erroneous arduino when I used the same setup and code with my own arduino (which I didn't had lying around when I was debugging). [crap! spent 2 full days on trying to solve this problem]

The erroneous one also heats up the ATmel chip when I connect it to 12V (no problem connecting to 9V by the way). It's definitely a goner, probably blown-up by it's owner.

Could I either way use your knowledge for one more question? It is one out of pure curiosity, I wondered what this thing was: IRF840 they call it a mosfet/hexfet. I am also curious in what a mosfet is.

If you're to busy, just ignore my topic and I want to thank you guys for helping me out and sharing some of your knowledge with me.
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