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31  Using Arduino / Project Guidance / Re: HELP Please - Idiot Dad tells his kid he can make a rocket launcher with a Ardui on: June 18, 2012, 07:26:58 pm
Ok, for the wireless you could use the xbee wireless module, or for cheaper, you could use a wireless adapter, and a router running openwrt. For the buttons and stuff I think you should break them down into pieces. ex: make that keypad so it can take the input and convert to a countdown, save that code and setup once you get it working. Next make a button that starts a timer, and save that code and get it working, then go to your fail-safe key etc. and when  you are done combine all the code. It's easier to troubleshoot when it's in small bits so you can locate the problem easier.
32  Community / Bar Sport / Re: What is the thing on Iron Man's chest? on: June 18, 2012, 07:17:24 pm
A nuclear fusion reactor I believe if I'm not mistaken.
33  Community / Bar Sport / Re: Measuring levels of carbon dioxide on: June 18, 2012, 07:16:41 pm
Arduino has a gas sensor that can detect many types of gasses. Try looking it up on ebay, sparkfun, or adafruit.
34  Using Arduino / Project Guidance / Re: Cheap DIY Speedometer on: June 18, 2012, 07:15:25 pm
Use a magnet, magnetic reed switch, and math. Attach the magnet, use the reed switch to detect when the magnet passes by therefore one revolution, then calculate speed based on wheel diameter.
35  Using Arduino / Project Guidance / Re: waterproofing a motor on: June 18, 2012, 07:12:48 pm
Use lots and lots of silicone.
36  Using Arduino / Project Guidance / Re: Audio connections to Arduino on: June 18, 2012, 07:11:05 pm
If you want 3.5 mm jack to wires, all you have to do is take an old pair of headphones or something else you don't want anymore, cut the wire to the size you want, and strip the wired.
37  Using Arduino / Project Guidance / Re: Sensor for bicycle speed? on: June 18, 2012, 07:09:04 pm
You could try a thin beam laser and a photocell to detect each spoke passing.
38  Using Arduino / Project Guidance / Re: heating control on: June 18, 2012, 07:07:07 pm
Use a stopwatch or timer instead of delay, delay will freeze the thread until the delay is up.
39  Using Arduino / Project Guidance / Re: Thermometer using the TMP36 on: June 18, 2012, 07:04:48 pm
I think you are better off using the thermometer library maybe that would work. The thermometer IC I got sends some type of serial messages, that may be what you are getting for the voltage. Just a suggestion I'm not familiar with your temp IC.
40  Using Arduino / Programming Questions / Revolutions Per Minute Calculating Error on: June 18, 2012, 06:59:15 pm
Can someone please help me with this code. It is supposed to detect the revolutions per second on a bicycle wheel and then convert it to revolutions per minute. The magnetic sensor code works fine, the timer resets itself when it passes by, but no matter what speed or increment of time i wait to pass the magnet by again, it only comes up with 2 readings 5,000 and 6,000, which are not goods revolution per second readings. I expect to get some number like 230.14 or something random like that. My code is below. Any help is appreciated.


Code:
//these are just some references for it to work properly
#include <StopWatch.h>
#include <LiquidCrystal.h>
//these are the microcontroller ports that an lcd screen is connected to, a status led, and the switch.
LiquidCrystal lcd(12, 11, 7, 6, 5, 4);
#define LED 13 //pin for the LED indicator (green)
#define Reed 3 //pin for the switch

//create a timer
StopWatch MySW;
//state of sensor 1 or 0
byte reedState=0;
//time between pass of magnet
float timeSincePass=0;
//revolutions per second
float RPS=0;
//revolutions per minute
float RPM=0;

//just some setup stuff
void setup()
{
  pinMode(LED,OUTPUT);
  pinMode(Reed,INPUT);
  Serial.begin(9600);
  lcd.begin(16, 4);
  lcd.print("Your Revs/Sec");
}


void loop()
{
  //get the state of the sensor
  reedState=digitalRead(Reed);
  //time since pass of magnet
  timeSincePass= MySW.elapsed();
  //set the lcd cursor to write on the second line
  lcd.setCursor(0, 1);

//if the magnet engages the switch
  if (reedState==HIGH)
  {
    //turn on status led for visual purposes
    digitalWrite(LED, HIGH);
    //convert milliseconds to seconds
    RPS=(float)timeSincePass*1000;
    //reset the timer storage int    
    timeSincePass=0;
    //reset the timer and start it again
    MySW.reset();
    MySW.start();
  }

  else
  {
    //turn off led otherwise
    digitalWrite(LED, LOW);
  }
  //convert seconds to minutes
  RPM=(float)RPS*60;
  
  //print the results to a screen
  lcd.print(RPS);
  lcd.print("  ");
  lcd.print(timeSincePass);
}
41  Using Arduino / General Electronics / Re: I need help setting this RFID up on: September 06, 2011, 07:47:47 pm
Thank you for your help bilbo. I will try to build one of those. I appreciate it.
42  Using Arduino / General Electronics / I need help setting this RFID up on: September 05, 2011, 06:39:34 pm
I got an
 RFID http://www.ebay.com/itm/250681401280?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1036wt_1177
and a
electronic door strike http://www.ebay.com/itm/300567444686?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_500wt_1198
Anyways I want to set up an RFID door security system. I have one problem. The electronic door strike is a fail safe which means when power is applied it locks and when power is failed or shut off it opens. The thing is is that the RFID outputs power when the key is brought near which will lock the door strike instead of opening it and the rest of the time it is insecure. Is there some way I can make an inverter or something that when it gets power it stops giving power to the door strike. I wanted to use an arduino board but the output and input is only 5 volts and I will be using 12. Any help I can get is appreciated.
43  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Reducing USB Power (5V to 2.7V) on: August 05, 2011, 09:35:59 pm
Try some resistors and transformers. Carefully calculate the right ones to use. I am not responsible for any broken arduino boards and I would hate for you to lose out on the fun you are having with your arduino.
44  Using Arduino / Motors, Mechanics, and Power / Re: cheap electric lock or strike on: August 05, 2011, 09:33:16 pm
The cheapest I have seen on ebay and other sites are around $30. I think they should be relatively easy to hook up to the arduino. I think you may want to use the digital ports and not the analog however because it should only be locked or open not in between. If you wanted analog a servo or motor connected to a deadbolt might suit you better.
45  Using Arduino / Motors, Mechanics, and Power / Question about motor external power supply. on: August 05, 2011, 09:29:08 pm
I don't think the arduino board with its mere 5v of output can put out enough power to power some motors and servos I have. Is there a way I can connect these to an external power supply like a power cord or wall socket and still have them controllable with the arduino board without overloading the arduino with too much amps or volts? I appreciate any help I can get.
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