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1  Using Arduino / Project Guidance / Max wire length for ultrasonic range finder on: August 18, 2012, 02:57:16 am
i have two big water tanks that i would like to setup a water level meter for
each tank is about 35-40 ft. away from where i would like the LCD to display the water levels and each tank is in the opposite direction.
after much reading, it seems an Ultrasonic sensor would be work well with my application.
Wireless is not an option as this is in a heavy rebar concrete building with many walls/floors in between, and i have no power source at the water tanks. I'm hoping to do this with one arduino and two sensors using cat 5 cables or anything similar.

my other option is to use 2 arduinos at the water tank locations which i am trying to avoid due to my budget.

Thanks
2  Using Arduino / Project Guidance / Re: RC Car, realistic lighting... Turn signals, brake lights, headlights etc. on: July 18, 2011, 10:52:40 am
RAM makes LED light kits for RC cars that can be hooked up the the rc's throttle channel and detect braking
you can use a Y servo connector on the steering channel to detect turns which would then turn on turning signal
do you know what spektrum radio does he use?
if its a pistol style most likely he only has 1 extra channel which by it self is very limited, some newer spektrum radios have built-in telemetry you would need the right receiver though
some thing like this

Quote
The DX3R PRO is packed with first-class software, including servo speed adjustment, ABS, traction control and 50-model memory. Built-in telemetry lets you monitor engine or motor temperature, keep tabs on engine rpm's or vehicle speed, track battery voltage, and check lap time, all in real-time.

Everything about the DX3R PRO is made to fit the way you drive, from the easy-to-read backlit screen to the large grip.


for controlling multiple things with a single channel you can use something like this
http://www.hobbyking.com/hobbyking/store/__12615__Multi-Remote_Receiver_operated_onoff_Switch_.html

and here you can find more lights
http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=280


Moe
3  Using Arduino / Project Guidance / Re: How to use millis function to turn led on for 5s then turn it off indefinitely? on: February 26, 2011, 02:11:13 pm
Code:
int ledPin = 13;
int leddone = 0;

void setup() {               
  pinMode(ledPin, OUTPUT);     
}

void loop() {
  if (leddone == 0) {
  digitalWrite(ledPin, HIGH);   // set the LED on
  delay(5000);             
  leddone = 1;
  }
}
4  Using Arduino / Project Guidance / Re: Device that senses motion and calls the house phone on: February 24, 2011, 12:17:09 pm
If the phone route doesn't work, you can have the arduino send you an SMS text message to your cellphone

All you need it to do when it detects motion is to send an email
Most carriers use email to SMS gateway like this
If I send an email to 5551231234@txt.att.net, it will send a text to that number
Here is a list with many providers and their gateways
http://en.wikipedia.org/wiki/List_of_SMS_gateways

And you can use something like GoBetwino to send emails
http://www.arduino.cc/playground/Interfacing/GoBetwino
5  Using Arduino / Project Guidance / Re: Arduino and PHP on: February 22, 2011, 06:47:19 pm
here's what worked for me

arduino code
Code:
if (Serial.available() > 0) {
   incoming = Serial.read();
 }
   if (incoming == (10)) {
      digitalWrite(ledPin, HIGH);
   }
    }

php code
Code:
<?php
require(
"php_serial.class.php"); //Initialize the class
$serial = new phpSerial(); 
$serial->deviceSet("COM4"); //Specify the serial port to use
//Set the serial port parameters. The documentation says 9600 8-N-1, so
$serial->confBaudRate(9600); //Baud rate: 9600
$serial->confParity("none");  //Parity (this is the "N" in "8-N-1")
$serial->confCharacterLength(8); //Character length (this is the "8" in "8-N-1")
$serial->confStopBits(1);  //Stop bits (this is the "1" in "8-N-1")

$serial->deviceOpen();
$serial->sendMessage(chr(10)); // start transmission

$serial->deviceClose();;    //We're done, so close the serial port again

   
header'Location: index.php' ) ;   // forward to index.htm
?>


the php code is called by a link from index.htm
it opens COM4
sends "10" through serial
closes COM4
sends the browser back to index.htm
6  Using Arduino / Project Guidance / Re: Arduino to turn on desktop PC on: February 18, 2011, 05:01:02 pm
Most servos work on 5v or 6v, you get more torque and speed if use
6v but will be fine if you connect it to the 5v on the arduino
Actually, there's a real possibility it'll overload the voltage regulator on the Arduino if it's required to do any real work.

It's always better to put motors on a separate supply.

Those black ABS cases are available from Radio Schlock, and from many mail-order suppliers.



Quote
The servo I purchased is 6V. If I just want to try it out what is the best way to power it? I bought the starter kit from Adafruit. It comes with usb, 9v plug in and battery connector.

he was asking if the servo will work with 5v instead of the specified 6v
so i meant to say the servo will work just fine smiley
normally digital servos are power hungry but since this is a standard it should idle around 15ma
the current will vary depending on how hard it works

 

7  Using Arduino / Project Guidance / Re: Measure time for a tank to empty by weight on: February 16, 2011, 10:02:14 pm
@Graynomad I wish I was < 25 smiley

Calculating flow shouldn't be a problem

Get a reading every 5 minutes
Old reading - New reading = flow in 5 minutes
(Full reading - New reading)  / flow X 5 minutes = time remaining


8  Using Arduino / Project Guidance / Re: Measure time for a tank to empty by weight on: February 16, 2011, 01:28:26 pm
you would need to weigh a few empty tanks and get an average, i searched around and most people say an empty tank weighs 18 lbs. and holds 20 lbs of propane so the total should be around 38 lbs for a full tank

you would need the arduino to store a reading from the scale every 5 minutes then it would be compared to the previous reading
so lets say we started with a half full tank containing 10 lbs of gas
the tank weighs 18 lbs + 10 lbs gas = 28 lbs
*the numbers should contain fractions to make things more accurate but i will skip them here

so the first reading is 28 lbs
5 minutes later the reading is 26 lbs
so in 5 minutes we used 2 lbs
since the scale now says we have 26 lbs and we know the tank by it self weighs 18 lbs
the arduino should know how much is left by (scale reading(26) - empty tank(18)) = 8 lbs of gas left
now since we used 2 lbs in 5 minutes then we can do this
(8 lbs left in the tank)    /    (2 lbs used every 5 minues) = 4 periods of (5 minutes)
4X5 = 20 minutes

sorry if its not clear, i posted this from my phone

Moe
9  Using Arduino / Project Guidance / Re: Arduino to turn on desktop PC on: February 16, 2011, 12:49:03 pm
FWIW a small solenoid can also be used to push buttons but for the sake of simplicity i recommended the servo which will do just fine
you just have to make sure the servo is secured and can't push it self instead of the button or push the button too far
10  Using Arduino / Project Guidance / Re: Arduino to turn on desktop PC on: February 16, 2011, 10:55:45 am
Most servos work on 5v or 6v, you get more torque and speed if use
6v but will be fine if you connect it to the 5v on the arduino
11  Using Arduino / Project Guidance / Re: Arduino to turn on desktop PC on: February 15, 2011, 08:49:21 pm
Good thing you got a big servo, it will be useful in many other projects
BTW if you want to glue the servo to a surface just make sure you wrap it with tape so you can reuse it
12  Using Arduino / Project Guidance / Re: Arduino to turn on desktop PC on: February 14, 2011, 05:29:11 pm
servos can be small or big and their power can vary
this will be fine for what you want to do
http://www.hobbypartz.com/topromisesg9.html

every desktop has a power light indicator, find that led and tape a photoresistor in front of it and attach a servo by the power button
you want that servo to press the button and then release it, so you have to experiment on how much the servo needs to move
you don't want to over push the servo in the button because that will strip the gears and make it useless

here is some code that should get you started
keep in mind i am a complete noob and wrote this really quick

Code:
#include <Servo.h> // include servo library
Servo myservo;
int lightPin = 1; // photoresistor is connected to pin 1
int val = 0; // store photoresistor value here


void setup()                    // run once
{
  myservo.attach(6); //attach servo to pin 6
}

void loop()                     // run over and over again
{

  val = analogRead(lightPin); // set val by reading the photoresistor

  if(val == LOW) { // if then photoresistor is showing low light), then..

    myservo.write(90); //move servo 90°
    delay(500); //wait half a second for the servo to get there
    myservo.write(0); //move servo back to 0°
    
}
}

you can unscrew the arm on the servo, so that you can test out the code without worrying about the gears
play with the 90 and 0 until you get it right

Moe
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