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16  Using Arduino / General Electronics / Re: Zener diode protection question on: November 24, 2012, 01:12:42 pm
also pay attention to zener diode temperature characteristics  smiley-twist
17  Using Arduino / Project Guidance / Re: Cheapest WiFi Module? on: November 24, 2012, 01:10:26 pm
wrt routers for ~20$
18  Using Arduino / General Electronics / Re: Solar Power on: November 20, 2012, 04:19:57 am
First of all, it depends on how much current would you draw...
If you plan to build projects with large motors, you won't be able to charge the batteries at all.
I recommend you find all electronics on ebay, and you will need batteries and solar panels + some kind of "charger" (voltage regulator).
For batteries i would personally go for some kind of Li- batteries, but my favorites would be LiFePO4.
For solar panels i would pick whatever size you need (depends on space available, power needed, etc.).
First you need to calculate the whole thing, to see how big system would you need...

If you can't make such calculations, feel free to post detailed specifications about your system.  smiley-mr-green
19  Using Arduino / Project Guidance / Re: Arduino + Xbee + 3G on: November 18, 2012, 01:04:58 pm
actually i stumbled on exactly what you need...
here's the link, enjoy  smiley-cool
20  Using Arduino / Project Guidance / Re: Arduino based class attendance devie on: November 16, 2012, 08:38:39 am
First its illegal to store someone's fingerprint.
Secondly, this method is easily crackable (1 person can register multiple users by using their fingerprints)

As result, you end up with 100$ less in your pocket...
21  Using Arduino / Project Guidance / Re: Read battery voltage remotely? on: November 16, 2012, 08:33:49 am
Any Arduino will do (Uno compatible / ATMega328 chip) and then you also need an ethernet shield, preferably one with a Wiznet W5100 chip. Combined the two should be less than $40. You can find lots of examples of how to serve a web page if you do a little searching.

To read your voltage you just need a couple resistors. If you have any interest in electronics you should buy an assortment pack of resistors, but if you just want to do this one project then a 10K potentiometer or seven 2200 ohm resistors would work (when combined to form a 8800 and 6600 ohm resistance). for an example.
this would be the "arduino" version...
but if 40$ is too much, there are some cheaper alternatives that require some dirty work, and also some knowledge...
personally, id cashed 40$ for elegant solution
22  Using Arduino / Project Guidance / Re: Vibrating motor musical instruent help on: November 16, 2012, 08:17:20 am
PWM  smiley-sleep
frequency - pitch
altitude - loudness

But i guess that the dynamic of the instrument would be inferior to the real instruments
23  Using Arduino / Project Guidance / Re: Simple led display on: November 16, 2012, 08:04:14 am
or you can always buy like 50 "ultra bright" leds for 5$, and make your own costumizable display on a 1$ ebay protoboard...
I can post the video of it if you want...
24  Using Arduino / Project Guidance / Re: Help with my first quadcopter on: November 16, 2012, 08:01:18 am
with the APM project, the transmitter and receiver are paired up. you can buy these together, of just research a bit of what receiver works with what transmitter. then, the receiver will plug into the flight computer (APM) - there is a graphic for this, channel 1 goes to input 1... etc.. then in software, you set the channel ranges, channel inversion among other things.

if you choose not to go this route, you will need to capture the output of the receiver and somehow integrate it with other sensors, to correctly drive the motors. there are some products for this, or you can hack the receiver to get the 'sum' signal out of the receiver to be used later in the flight computer sensor chain.


More time you spend preparing, more easy it will be to build one.
So why wouldn't you make some calculations about the hardware first, to make sure will the thing even fly.... smiley-mr-green
25  Using Arduino / Installation & Troubleshooting / Re: Loop Back Test Failed on: November 16, 2012, 07:56:19 am
then the avrdude message is displayed

What avrdude message?

common problem on forums, still no anwser
26  Using Arduino / Installation & Troubleshooting / Re: Arduinio Mega ADK won't accept code on: November 16, 2012, 07:55:35 am
Hi guys!

The troubleshooting page led me here.

I am using an Arduino Mega ADK to receive Output from some flow-meters and pressure-sensors. There is also a 2.8" Adafruit TFT attached, to visualize the data (nothing fancy or complex; just printing the input-values to it) and the Ethernet Shield as the Mega is also a webserver. Furthermore, the Arduino generates PWM-signals to control a pump via a DC/DC-Converter.

After ~5 weeks of working with the Mega ADK (in which I uploaded not more than 500 times) it just won't accept my code anymore. The IDE starts to compile (my code is about 600 lines - calculating some things), then tries to upload but nothing happens. When the IDE finally starts trying to upload, the attached TFT flashes to white, a normal thing I observed when uploading. But after a second, the Mega seems to reset (while the IDE uploading progress bar is still visible), and then just starts the programm that was already on the EEPROM, disregarding the whole new upload, which would be - considering the one second - uncomplete.

Of course I tried to upload code with only the Mega attached, using the Blink-Basics-example, trying a different cable and used a different computer (Windows7). Didn't change the situation. Bootloader seems to be working, as the L-LED blinks twice when the Arduino is connected. All computers are succesfully installing the drivers for the Mega, and it's also visible in all the Hardware Managers.
I didn't install new software but I added an Eclipse plugin in order to comfortably setting up some handmade libraries. I didn't use them yet and changed nothing in the Arduino lib's itself. Can't imagine that there's a problem with Eclipse.

I also don't get any error in the IDE, it just tries to upload forever until I close it. Holding down Shift before clicking upload got me the verbose error "avrdude: stk500_getsync(): not in sync: resp=0x00". I then usualy disconnect the Mega and its shields, plug only the Mega itself in and try again and it works. Well, until now...

I hope to have provided some usefull infomation and I am hoping someone of you has an idea what I could try next. smiley-sad

EDIT: Went through the Loop-Back Test, with positive results.
there are many problems with megas, perhaps it is atmel's fault
27  Using Arduino / Installation & Troubleshooting / Re: Upload Timeout Error on Mega 2560 - Not Sure What Changed on: November 06, 2012, 05:20:54 pm
Hey All,
    I had a similar issue when I was trying to use an Uno as a boot loader, and I think the trick is that the chip is getting reset part way into the upload. The reasons this seems plausible are :
A - someone mentioned it looked like his board had reset
B - after a half-assed attempt at uploading, my board just starts up the old code (i.e. looks like it reset)
C - It seems correlated to length of code, and I have no issue uploading the blink code, ever.
    Anywho, the hardware solution to this software problem is to toss a BFC (10uF or so, I used an electrolytic) between the Reset pin and ground. What this does is it stops the device from getting reset by little transients that I believe are associated with the serial printing stuff.
    Hope this works for Y'all, in the end I got it working with Arduino 023 and a 49K program.

EDIT: This worked great briefly but now it has gone back to it's old ways of not working.

Salvage usable components and throw the rest away...
28  Using Arduino / Programming Questions / Re: storing data from sensors on: November 05, 2012, 05:23:11 pm
at first glance i doubt the code would read values from the sensors
this function read all the sensors. I am using 3 HC-SR04 sensors that use 2 pins to make the readings

Ok if you tried it, then sry....
Because my HC-SR04 gave me a headache, and i ended up doing something more complex than you wrote...  smiley-mr-green
29  Using Arduino / Programming Questions / Re: storing data from sensors on: November 05, 2012, 04:57:46 pm
Hi, I am making a robot that uses 3 ultrasonic sensors to navigate through a path. I want to get the values that the sensors provide for a given path and store them somewhere. How can I do that. To read all three sensors I use an array already is there a way that I can get all the arrays and store on a matrix or something? Here is the code of how I read the sensors.

int ping(int j) {
  int duration, distance;
  pinMode (trigPin[j], OUTPUT);
  pinMode (echoPin[j], INPUT);
  digitalWrite(trigPin[j], LOW);
  digitalWrite(trigPin[j], HIGH);
  duration = pulseIn(echoPin[j], HIGH);
  distance = (duration/2) / 29.1;
  return distance;
void loop(){
  int minimum, Position, distance[3], j;
  for (i=0; i<3; i++){
  delay (35);

at first glance i doubt the code would read values from the sensors
30  Using Arduino / Installation & Troubleshooting / Re: Can not upload to MEGA 2560 anymore on: November 05, 2012, 04:55:24 pm
Hello all, I'm hoping you can help me with a problem we're having.

One of our many MEGA 2560s is no longer accepting uploads. The currently-uploaded sketch works fine, however (that is, we've been able to upload to it in the past). This has been tried on three different PCs (all running Win XP) using Arduino 1.0 or greater; these PCs have no problem uploading to any other MEGA 2560 we have in-house. I see no evidence of physical damage either.

The upload process never completes; LED13 flashes once, then a quick blink from the TX/RX LEDs, and then nothing. If I enable verbose mode on upload, I see:

    avrdude: Version 5.11, compiled on Sep  2 2011 at 19:38:36
             Copyright (c) 2000-2005 Brian Dean,
             Copyright (c) 2007-2009 Joerg Wunsch
             System wide configuration file is "C:\Documents and Settings\astavrow\Desktop\arduino-1.0.1\hardware/tools/avr/etc/avrdude.conf"
             Using Port                    : \\.\COM10
             Using Programmer              : stk500v2
             Overriding Baud Rate          : 115200
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: Recv:
    avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: Recv:
    avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: Recv:
    avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: Recv:
    avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14] avrdude: Recv:
    avrdude: Recv:
avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: Recv:
    avrdude: stk500v2_ReceiveMessage(): timeout
    avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
    avrdude: stk500v2_getsync(): timeout communicating with programmer

This repeats ad nauseum for as long as I leave it running. For the record, in troubleshooting this issue I'm trying to upload the 'Blink' example sketch, that is, well-known and well-tested code.

I tried running the loopback test but nothing was echoed back. Similarly, I can't open a connection to the serial port, or rather, I get no reply from the MEGA 2560 in question when I do.

Pressing the reset button gets LED13 to blink twice, so I believe this means the bootloader is okay; please correct me if I'm wrong about this.

There is no apparent damage, although one person on our team suspects they saw an ESD event when connecting the cable from the MEGA 2560 in question to the PC (at the PC port, which appears to have come through unscathed). I can't corroborate this.

Oh yes, and lest I forget, I have "Arduino MEGA 2560 or Mega ADK" selected as the board, and the correct COM port is selected to.

Any thoughts on how I can further test this before declaring the board KIA?

Thanks in advance.
If its a "fake" (ebay, sparkfun, etc.) throw it in junk...
If its an original, try to spam on forums for help (i remember my post had like 100 000 views, but no solutions that worked)...
If you don't get help you can always salvage connectors from the board and then throw it in trash...
Best regards, xXvjeko
P.S. there are cheaper faster mega alternatives like Microchip's 32'bit pickit for 49$ (original) with more outputs and more powa  smiley-twist
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