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61  Forum 2005-2010 (read only) / Interfacing / Re: Getting output from GPS on: November 24, 2009, 07:46:04 pm
Woohoo!  I got one!
62  Forum 2005-2010 (read only) / Interfacing / Re: Getting output from GPS on: November 24, 2009, 05:53:26 pm
You do have the receive pin of the GPS hooked up to the transmit pin of the arduino and vice versa right?  I know that when I picked up a GPS module that threw me for a moment...
63  Forum 2005-2010 (read only) / Interfacing / Re: Homemade hall effect compass on: November 24, 2009, 09:18:11 pm
Perhaps the solution isn't to amplify the signal, but to increase the sensitivity.  What if you used an external 12 bit i2c ADC?  That would give you a @ 1mV sensitivity (5V/4096).
64  Forum 2005-2010 (read only) / Interfacing / Re: Homemade hall effect compass on: November 23, 2009, 04:16:07 pm
Honeywell HMC6352 -
http://www.sparkfun.com/commerce/product_info.php?products_id=7915

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=342-1041-5-ND

http://www.parallax.com/Store/Sensors/CompassGPS/tabid/173/CategoryID/48/List/0/Level/a/ProductID/596/Default.aspx?SortField=ProductName%2cProductName

Hitachi HM55B -
http://www.parallax.com/Store/Sensors/CompassGPS/tabid/173/CategoryID/48/List/0/Level/a/ProductID/98/Default.aspx?SortField=ProductName%2cProductName

Are two additional examples.
65  Forum 2005-2010 (read only) / Interfacing / Re: Homemade hall effect compass on: November 23, 2009, 02:56:47 pm
Those 8 point compass modules are used in some vehicular applications, so you may find one locally by pursuing that avenue rather than ordering them internationally.  Perhaps they may even be available used (even more inexpensive) at a automotive scrap yard.
66  Forum 2005-2010 (read only) / Interfacing / Re: Homemade hall effect compass on: November 23, 2009, 01:11:13 pm
Depending on what your doing, couldn't you use one of the less expensive 8 point compass modules and use interpolation (i.e I must rotate the sensor x number of stepper steps/servo degrees before it changes the reported orientation) to approximate greater resolution?  I mean sure if your not using this on a bot or something that could achieve a precisely aligned set of steps, that would preclude this tactic... but if you are, then you could recalibrate it on start up each time and not have to deal with the frustration of noise.
67  Forum 2005-2010 (read only) / Interfacing / Re: Dimming leds on: November 23, 2009, 09:18:17 pm
PWM (Pulse Width Modulation) is you friend.  Simply use analogWrite() to pulse the power on and off rapidly to your LEDs.
68  Forum 2005-2010 (read only) / Interfacing / Re: Basic Motion Detection on: November 23, 2009, 04:57:34 pm
You could use the standard IR transmitter/receiver pairs across the doors.
69  Forum 2005-2010 (read only) / Interfacing / Re: Indoor localization without gps? on: November 18, 2009, 04:17:34 pm
Sure, the view of the ceiling could be blocked, but if you did a hybrid of dead reckoning... i.e. guess where you are by quadrature but verify when possible, you'd decrease the innate inaccuracy of dead reckoning alone because you could recalibrate your location.

I'm pretty sure it would work so long as the ceiling were reflective enough.  If it was acoustic dampening foam tiles, that might make picking up the reflection difficult.
70  Forum 2005-2010 (read only) / Interfacing / Re: Indoor localization without gps? on: November 18, 2009, 01:32:58 pm
What if...  and mind you I am just speaking off the cuff here...  You had an IR receptor on your bot that looked at the ceiling.  Then you had a set of IR lasers that were passed through a laser line generator and shown at the ceiling.  These lines could be scanned across the ceiling using mirrors one going across in the X direction and the other in the Y direction. information could be pulsed to the laser in turn at each orientation, then advanced to the next orientation and different information pulsed (i.e. a code for say the current angle).  You could in theory set up a rudimentary means of triangulation based upon what information was flashed at the ceiling directly above your roving robot.  In this way, the robot could glean an X,Y fix in the room, by simply reading the information from above.

Am I nuts?
71  Forum 2005-2010 (read only) / Interfacing / Re: Indoor localization without gps? on: November 17, 2009, 02:50:09 pm
What if you buried or attached an array of RFID tags in the floor?
72  Forum 2005-2010 (read only) / Interfacing / Re: Comminication between Arduinos  - powerline or RF? on: November 12, 2009, 04:49:33 pm
How does one send information via the AC wiring?  
73  Forum 2005-2010 (read only) / Interfacing / Re: Converting a circuit to Arduino on: November 03, 2009, 09:20:04 pm
So,  I'm taking it that the new schematic would look something like this:



I assume the 2.2K resistor would no longer be valid when taking the changed voltage into account (i.e. from 9v to 5v)?  So what might the value be (and why)?
74  Forum 2005-2010 (read only) / Interfacing / Re: Converting a circuit to Arduino on: November 03, 2009, 07:40:49 pm
Well not totally...  The potentiometer (if I understand things correctly) constitutes a voltage divider.  So you are measuring a voltage difference between that median voltage and the voltage flowing through the FET.  In the case of this circuit the supply voltage is 9V and if one assumes that the potentiometer is centered resistance-wise...  one would assume that a voltage flowing through the FET below 4.5 volts would be considered a "negative" result...  Or am I mistaken?
75  Forum 2005-2010 (read only) / Interfacing / Converting a circuit to Arduino on: November 03, 2009, 06:38:09 pm
Some things I understand just fine others I'm pretty new to.  Can someone explain how they would convert the circuit found here: http://www.zen22142.zen.co.uk/Circuits/Misc/staticdet.htm ...  To replace the meter with one of the Arduino's analog inputs?  I'd really appreciate it.
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