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151  Forum 2005-2010 (read only) / Interfacing / Re: Motorola V3i RAZR on: May 24, 2010, 06:04:13 am
It looks as if you have the information you need, then.  The next problem is removing the parts and connecting them to your own board.  That may be near impossible to do.  I usually buy parts from some place like spark fun.  It's not free, but they have things on nice breakout boards so you can interface the parts much more easily.
152  Forum 2005-2010 (read only) / Interfacing / Re: Multiple buttons connected to an Arduino board on: May 20, 2010, 06:35:22 pm
You need to use the internal pullups.  digitalWrite(pin, HIGH) this turns on the pullups.  Do this for each of your pins.  Otherwise, the pins are left floating.  You can then use the switches to pull the pin to ground.  Remove the 5V from the circuit and it should work much better.
153  Forum 2005-2010 (read only) / Interfacing / Re: pool temperature monitoring on: May 19, 2010, 11:56:35 am
I've used a thermistor with no problems.  I could share some code that I found in someone else's post if you want.  I have a 1-wire sensor that I haven't tried to interface yet.  Those look like a pretty good option also.
154  Forum 2005-2010 (read only) / Interfacing / Re:  Atmega 328 on: May 13, 2010, 05:38:46 pm
There is a software serial library that should be of use to you.
155  Forum 2005-2010 (read only) / Interfacing / Re: LM335Z - Temp Sensor on: May 10, 2010, 11:21:38 am
What he was saying is that you can use the Arduino power supply (+5V) to connect to the power pin on your temp sensor.  Ground on the temp sensor goes to ground on the Arduino.  Analog pin on the temp sensor goes to the analog pin on the Arduino.  Does this help clear it up?
156  Forum 2005-2010 (read only) / Interfacing / Re: Integrating different sensors together and display on: May 06, 2010, 11:28:37 am
Check your pins.  You may be calling for the same pins to be used in the software for both sensors.  Make sure your LCD isn't using some of the sensor pins you need.  You may not have set up your pins correctly.  If you're using the Sensirion sensor, it needs two pins to talk.  If you're using analog pins, you need to call them as pins 14, 15, 16, 17, 18, 19, or 20 to use them as digital I/O.  It would also help to see the code you're using.

I'm currently using an LCD, DS1307 clock, Sensririon SHT-11, and OpenLog at the same time with no issues.
157  Forum 2005-2010 (read only) / Interfacing / Re: DS1307 returns all 0s on: May 08, 2010, 07:10:26 pm
I have a sample DS1307 that I ordered from Maxim.  I built a board with a crystal and battery.  Until I got mine connected correctly, it "responded" with all 0s as well.  I'm using the same code.  Make sure you have your pins connected correctly.  You must also have 5V and ground connected to the clock module.  Instead of having to use the memory dump, I added the following to my program.  This just retrieves the time and date and prints it through the serial monitor.  I actually had progressed to saving the time and date for 7 different events into the clock SRAM.  I used the following as a learning step to get there.  Good luck!

  else if(command == 67){ //If command = "C" RTC1307 Get Time and Date
      Serial.println(" ");
158  Forum 2005-2010 (read only) / Interfacing / Re: multiple buttons on: May 03, 2010, 02:50:35 pm
Does it matter how many pins are used?  You could use individual digital pins, or you could use a few analog pins.  Will you be connecting other devices to the Arduino?
159  Forum 2005-2010 (read only) / Interfacing / Re: LCD issue... not displaying SPACE character on: April 24, 2010, 06:05:48 pm
Try printing the same character for all 16 character locations.  This should tell you if the LCD is working properly.  From the sound of it, I think your LCD may have a problem.  You may find that there are certain locations that won't print while others will.  Please let us know what you find out.

Is this a new display or is it used?
160  Forum 2005-2010 (read only) / Interfacing / Re: humidity controlled mister on: April 21, 2010, 08:04:23 am
I use the Sensririon SHT-11.  It's a good sensor to use and the library already exists.  I have one set up and use it with an LCD.  I could provide some code to help if you choose to use Sensirion.
161  Forum 2005-2010 (read only) / Interfacing / Re: Arduino + Air Conditioner = ??? on: April 01, 2010, 02:58:50 pm
You could use PID if you want to get fancy.  If you want to keep it a bit simpler, you could use low speed for temperatures within 1 or 2 degrees of the setting.  If it gets outside of that setting you may want to switch to high speed.  You may also want to incorporate some timers that would force some hysteresis.  Example: once it switches on, it must run for some minimum time.  In the same way, once it switches to high, it must run for some minimum time before switching back to low.  Your stage-up timer may not be the same as your stage-down timer.

You'll need to decide if you want it to be able to go low-high-low-high and so on, or if you want it to ratchet up from Off to Low to High and then back to Off.  Each scenario will require different algorithms for control.  You'll also want to make sure that it stays off for a few minutes after it shuts down in order to allow the refrigerant to equalize throughout the system.  This protects the compressor from trying to start up under load.  Most A/C manufacturers use a 5 minute off timer.

Happy coding!
162  Forum 2005-2010 (read only) / Interfacing / Re: Seismograph? on: March 28, 2010, 06:11:35 pm
I saw an interesting idea in a Forrest Mims book from Radio Shack.  He took a magnet and suspended on a string above a coil.  If the magnet was disturbed (by shaking), it would swing back and forth.  This would create a voltage and current in the coil.  The strength of the voltage and current would be dependent on the amount of swing.  He had suggested installing this in a tube so that air currents wouldn't disturb it.  He also suggested mounting it on a concrete pad, such as in a garage.
163  Forum 2005-2010 (read only) / Interfacing / Re: help with sequencing leds on: April 01, 2010, 02:51:05 pm
I did something kind of like this.  I used the random() command to choose the time between blinks.  blink_delay = random(500, 4001);  This gives a random number between 1/2 second (500ms) and 4 seconds (4000ms).  If you must have a whole number, I used an array and then used random() to choose which one to blink.  Initialize with this statement:  const byte pwmPins [] = {3, 5, 6, 9, 10, 11};  and use the random choice like this:    pwmPin = pwmPins [random (0, 6)];

Hope this will help get you started.
164  Forum 2005-2010 (read only) / Interfacing / Re: Oil tank Level sensor? on: March 02, 2010, 08:49:32 pm
I love that Kitplanes fuel gauge.  I didn't realize that the site was still there with the plans.  Jim Weir is a great electroniker.  I miss reading his columns.  Glad to see there are others who have gotten ideas from his work.
165  Forum 2005-2010 (read only) / Interfacing / Re: Using EEPROM chips? on: February 06, 2010, 04:17:33 pm
Since this is something you're not familiar with, it is going to take some time to understand.  I have the same problem.  I would suggest going here to study.  Your chip communicates via serial.  This comes from the datasheet.  It will take some time to understand exactly what the datasheet is telling you.  I still don't understand everything that it says.  I rely heavily on libraries written by others because I'm not a programming wizard.  I have, however, been playing with electronic circuits long enough to know that you won't figure it out overnight, or at least, I don't.  Do some reading, look for examples, take some time off and digest, then come back and do some more.  The old adage says, "How do you eat an elephant?  One bite at a time."  Be patient.  You can learn this, but it will take time.
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