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16  Using Arduino / Project Guidance / Re: Collision avoidance on: February 10, 2014, 08:39:57 pm
The arduino can process a serial JPG image.  Or a Raspberry Pi can much faster.  Can you think of a better way instead of a laser to avoid a collision?
17  Using Arduino / Project Guidance / Quadcopter Follow me on: February 10, 2014, 01:18:40 pm
I've got 2 ideas to make a Quadcopter follow me while walking.  GPS is not one of them.  
18  Using Arduino / Project Guidance / Collision avoidance on: February 10, 2014, 01:08:45 pm
How can I detect a tree, human or vertical post from 10ft away?  
19  Using Arduino / Motors, Mechanics, and Power / Re: Build or buy Galvo for Laser mirrors? on: February 01, 2014, 10:44:27 am
Thanks for all the ideas!  Please anyone let me know if you have success building one of them.  For the moment I'm working on our Flying Robot...
20  Using Arduino / Project Guidance / Detect angle between 2 devices on: January 19, 2014, 10:01:45 am
I'm hoping you experienced Robot builders can help me with some brainstorming for a new project.  I need to turn a "robot" to face a human.  The human could be carrying an iPhone with GPS, ultrasonic sensor, laser reflector, anything small.  Within 15-30 degrees would be close enough.  I also need to calculate distance, that's the easy part.  So they will already be carrying an ultrasonic device to repeat back the ping.  GPS is not good enough because they may be less than 30 feet apart.  At larger distances this may be the best solution.  I have tried a laser on a stepper, this works so long as there is a Retroreflector mounted on the human.  The device below has a stronger signal when pointed within 15 degrees.  Is that the simplest solution?  The range is not enough with a passive reflector.  What range would I get with another ultrasonic device to ping back?

http://letsmakerobots.com/node/30209
http://en.wikipedia.org/wiki/Retroreflector

How about 2 IR sensors with a wall between them?  A stepper to turn it until both are equal?  What are the pros and cons for this method?  Range?

If there were an accurate (100us) clock synched on both ends a laser could scan back and forth.  All that is needed is the time of the received beam to calculate the relative angle.  More ideas?
21  Using Arduino / Motors, Mechanics, and Power / Re: Build or buy Galvo for Laser mirrors? on: January 19, 2014, 09:16:18 am
Not sure how to use one.  I tried Google.  Any more links?  What is the lowest cost?
22  Using Arduino / Motors, Mechanics, and Power / Re: Build or buy Galvo for Laser mirrors? on: January 16, 2014, 02:11:32 pm
Has anyone done it with a Stepper Motor?  What type is best?
23  Using Arduino / Motors, Mechanics, and Power / Re: Build or buy Galvo for Laser mirrors? on: January 08, 2014, 11:02:44 pm
A solenoid is all or nothing right?  I have read of a few people using a stepper motor with one coil energized at 50% then you modulate the adjacent one to achieve an analog movement.  This will give you a maximum of one step, which may be enough.  What type of stepper would I use for this?  I am familiar with many steppers, but never for this application.
24  Using Arduino / Motors, Mechanics, and Power / Re: Stepper Motor Hardware and couplers for 28BYJ and other steppers / motors on: January 07, 2014, 01:05:35 pm
What is the minimum current you can set for this board?
http://www.pololu.com/product/1182
25  Using Arduino / Motors, Mechanics, and Power / Re: Control two 5v stepper motors with single arduino board on: January 07, 2014, 12:58:38 pm
Good advice.  But it is possible with your board.
26  Using Arduino / Motors, Mechanics, and Power / Re: Build or buy Galvo for Laser mirrors? on: January 07, 2014, 12:56:17 pm
@jackrae- I tried pulsing my laser while the mirror is spinning.  At a slow RPM I cannot make a dot, but a line nearly 1 degree long.  With a shorter pulse the line is dim.  Any idea why?

Chan's tutorial sounds like the best solution for someone who has a lot of time on their hands.  Can anyone think of a shortcut?  Something to buy for cheap?  An experiment to try?  I wouldn't mind learning something along the way.
27  Using Arduino / Motors, Mechanics, and Power / Build or buy Galvo for Laser mirrors? on: January 07, 2014, 01:14:37 am
Was looking online for a way to control mirrors for a laser.  Closed loop feedback would be ideal, but I'd be willing to try no feedback like a speaker or meter movement.  How can I build something to experiment with?  Can I use a brushless R/C motor to move 5 degrees with many analog steps in between poles?  A linear actuator?  Hard drive linear motor?  Where can I find these or an old HDD?  I've tried a stepper but with gears it's not fast enough I'd like 1-2kpps.  Without gears it can move back and forth 1.8 degrees quickly, but not in between.  Any ideas to help me brainstorm?
28  Using Arduino / Motors, Mechanics, and Power / Re: 28BYJ-48 5-Volt Stepper on: January 07, 2014, 12:53:37 am
All that you said makes sense to me.  You can get 35RPM by using a higher voltage with these tiny motors!
29  Using Arduino / Project Guidance / Re: Detect interference from power lines on: January 02, 2014, 09:01:09 pm
How can I measure this field?
Ignoring the type of receiver used for a moment.
30  Using Arduino / Project Guidance / Re: Detect interference from power lines on: January 02, 2014, 05:09:30 pm
A cell phone transmitting conversation does not interfere with a modern 2.4ghz radio.
Not even inches from the receiver, while the transmitter is 0.38 miles away.
I have heard pilots say it interferes NEXT TO THE TRANSMITTER while flying!
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