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16  Using Arduino / Programming Questions / Re: Sending Analog Sensor Data Between XBees on: July 04, 2014, 06:29:16 am
strtok or strchr are useful C string handling functions for this kind of simple parsing.
17  Using Arduino / Programming Questions / Re: Developing with c++ on: July 03, 2014, 01:54:44 pm
The "arduino language" question comes up fairly frequently.

Here's a thread on the topic: http://forum.arduino.cc/index.php?topic=199751.0
18  Using Arduino / Project Guidance / Re: Would appreciate some help on my Xbee project! on: July 03, 2014, 08:56:29 am
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I guess the only thing left is that perhaps my xbees are defective?

Perhaps. I have a vague recollection that when I had some series one XBees that I had to do some configuration with X-CTU to get them to talk to each other. I think the later ones just work out of the box.

Or it's your code - post your revised versions.
19  Using Arduino / Programming Questions / Re: Which arduino is the most powerful ? on: July 03, 2014, 08:40:34 am
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I want to measure the distance of an object using ultrasonic transducers (40kHz).

Usually, this is done using pulsin and doesn't require sampling at 100kHz. Check the ping example that comes with the IDE.
20  Using Arduino / Project Guidance / Re: Would appreciate some help on my Xbee project! on: July 03, 2014, 08:21:14 am
You're not reading the incoming data in such way that you can ever get 1111. Try using 1 and 0 to get the thing working.
21  Using Arduino / Project Guidance / Re: Hhelp for miniature house automation!! on: July 03, 2014, 06:38:26 am
Which Arduino you need chiefly depends on how much I/O you're going to need i.e. how many things will be controlled in your miniature house. So you need to figure out your requirements before you can choose wisely. If the controller program turns out to be very complex (seems unlikely) you may be pushed towards the Mega because it has more memory.
22  Using Arduino / Project Guidance / Re: remote thermometer for a pool on: July 02, 2014, 01:40:32 pm
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Originally, i had hoped to get a wireless pool thermometer that transmits an RF signal and try to capture that.  From what i have been reading, that is not really feasible.

What's the issue with this approach?
23  Using Arduino / Project Guidance / Re: need some guidance on: July 02, 2014, 06:26:35 am
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how I want the 3 ping sensors to work is if a value of < 15 cm is returned it would tell pin 30, etc. to turn off  pumps and when it returns a value of > 40 cm is returned it would tell pin 30,etc. to turn the pumps on , then start a timer and if the pumps takes longer than 3 minutes to fill the tanks so that the ping sensor returns the < 15 value it will turn the pump off to avoid an over-fill situation in any one of the 3 tanks

Be careful in this situation to lock the pump out from further action. Otherwise, simple code would just note again that that the water level is low & pump for three minutes again and again - flooding is nasty!
24  Using Arduino / Motors, Mechanics, and Power / Re: Micro-solenoid not working? on: June 30, 2014, 02:19:44 pm
The playground has a circuit for solenoids: http://playground.arduino.cc/uploads/Learning/solenoid_driver.pdf. Don't forget the diode.

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I did notice something, though: when I connect the solenoid directly to the +5V power source and the ground of the Arduino, the solenoid moves "to the other end" in an instant.

That's expected behavior.
25  Using Arduino / Sensors / Re: Data from DHT22 and BMC085 gets cut in a long string on: June 30, 2014, 01:48:18 pm
Post your code.
26  Using Arduino / Motors, Mechanics, and Power / Re: Micro-solenoid not working? on: June 30, 2014, 01:43:53 pm
The arduino digital I/O pins can provide 40mA max and to ensure that your arduino has a long life, it's recommended that you not exceed half of that. It sounds as though your solenoid needs more power - you'll need to use your transistor to switch the 5V supply directly rather than trying to run it off one of the pins.

It's possible too that you've already damaged the pin you were trying to use - might be worth testing it with an LED and suitable resistor.
27  Using Arduino / Project Guidance / Re: question, delay or not , how to do on: June 29, 2014, 07:47:23 am
Do you want to be able to use an input device to tell the arduino how long to keep the LED on? A potentiometer read on an analog pin would be one way. Or are you saying that you want to be able to specify the time as a constant in the sketch?
28  Using Arduino / Project Guidance / Re: Tennis Ball Machine on: June 29, 2014, 06:44:27 am
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It looks as though that design allows for topspin and backspin; it would be nice if it were possible to rotate the firing wheels assembly so that you could do left & right too.
29  Using Arduino / Project Guidance / Re: Continually Changing PID Setpoint on: June 27, 2014, 12:34:29 pm
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My first thought was to use a second PID object that takes food temp as input, blower's setpoint as output, and food target as it's setpoint.

I wonder how well this would work if you made this the primary (and only) PID.

Or just wait until the food is mostly up to temp (80%?) and then set the BBQ set point to the desired final food temp.
30  Using Arduino / Project Guidance / Re: Whiskey dispenser on: June 27, 2014, 06:52:23 am
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Only thing I would need to figure out, is how to seal the bottle when not in use - preferably without taking the tubes up of it. No fun in dust getting in, and alcohol evaporating. But would still need to allow air to get in when pump is on.
It sounds like overkill to have a T-junction with the pump on one side, a solonoid on the second and the bottle on the third. When pumping, solonoid is opened to allow air to get in. It could work of course, but is it the best way? Seems like a lot to have a solonoid "just" for that, no?

Optics will solve all of this for you - you just need a mechanism to open them - as in the link I posted earlier.
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