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31  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Would like menu option for AVR-based programmi on: September 09, 2008, 08:34:00 pm
Quote
Because coding preference dialogs is annoying as hell smiley smiley smiley

But anybody who wants to do it is welcome to contribute it to the code

massimo

I'd love to contribute (time permitting.)  I'm the lead architect on a large, Java-based project, so I have some skills.  What's the best way to help out?

Wayne
32  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Would like menu option for AVR-based programmi on: September 09, 2008, 08:26:23 pm
Quote
IIRC, version 12 will allow direct programming in the boards.txt file, so you could do a one-time edit of that file and have an entries like "ATmega8 via AVRISPmkII" or "ATMEGA168 via USBtiny"

-j


That seem like a workable solution.  Thanks.

Wayne
33  Forum 2005-2010 (read only) / Bugs & Suggestions / Would like menu option for AVR-based programming on: September 09, 2008, 01:54:28 am
I've read the instructions here:

   http://www.arduino.cc/en/Hacking/Programmer

and I'm very grateful that I have the option to directly program the MCU with my AVR-ISP.  However, as I also program my regular arduino boards quite frequently, it would be nice to have a menu option to switch between these different options rather than have to drill down and edit the preferences.txt file each time.  I would suggest adding a "Program Via" option in the Tools menu that would contain these options:

  Bootloader (default)
  AVR ISP
  AVRISP mkII
  USBtinyISP
  Parallel Programmer

Just a thought.

Wayne
34  Forum 2005-2010 (read only) / Interfacing / Re: Controlling 1000's rgb leds on: November 20, 2009, 12:30:41 pm
Take a look at this product from SparkFun:

  http://www.sparkfun.com/commerce/product_info.php?products_id=760

The schmatic and firmware are both freely available and it might give you some ideas.

Wayne
35  Forum 2005-2010 (read only) / Interfacing / Re: Colour Recognition Sensor on: February 07, 2010, 05:44:23 pm
Take a look here:

  http://www.sparkfun.com/commerce/product_info.php?products_id=8618

Wayne
36  Forum 2005-2010 (read only) / Interfacing / Re: Appropriate sensor to detect bicycle steering? on: November 17, 2009, 06:01:49 pm
I would look into the magnetic encoder used in the RepRap project.  More details are here:

  http://reprap.org/bin/view/Main/Magnetic_Rotary_Encoder_1_0

In absolute encoder mode, the IC used on this board has a 10-bit resolution providing 1024 absolute positions per 360° (step size ~ 0.35°)

You can get samples of the IC directly from Austria Microsystems, too.

Wayne
37  Forum 2005-2010 (read only) / Interfacing / Re: Pet Cam Project on: November 12, 2009, 11:01:02 pm
You still can.  I pointed you to this link because there are circuit diagrams and other info you can use as a starting point.  I thought that was what you were asking for.  Information...
38  Forum 2005-2010 (read only) / Interfacing / Re: Pet Cam Project on: November 12, 2009, 09:10:04 pm
Check here:

  http://www.mr-lee-catcam.de/

'cause it's been done.

  
39  Forum 2005-2010 (read only) / Interfacing / Re: rotating power transfer for small projects? on: September 22, 2009, 05:40:18 pm
Check out this link:

  http://www.mercotac.com/

Wayne
40  Forum 2005-2010 (read only) / Interfacing / Re: Foot position sensing on: December 03, 2008, 06:00:04 pm
I think there are a few unstated issues you're not considering:

First, there's the issue of how to tell which end is the toe and which is the heel.  Many types of shoes are nearly symmetrical is this regard, so it might be very difficult to tell which end is the toe even if you could capture a complete scan of the sufaces in contact with your pad.

Even if you had a very fine grid of pressure sensors and tried to find the toe end by seeing which end pressed down with ledd weight, this would still change as someone shift weight back and forth while walking.

One thing that might work would be to have a two level array of optical beam sensors (infraread LEDs on one side and phototransistors on the other.)  One level would be at heel height and the other at ankle height.  Using this, you might be able to ciscern foot orientation comparing the points of intersection detected by these arrays.

It might be hard to deal with the issue of one foot shading the other from the scanners, but good detection algorithm might be able to deal with this.  Just a thought.

Wayne
41  Forum 2005-2010 (read only) / Exhibition / Re: Magnetic Core Memory for Arduino on: August 21, 2010, 11:37:51 pm
On a tangential note, in the course of learning about how magnetic core memory works, I stumbled across an article on how later model Seeburg jukeboxes (the ones made between 1955 and 1978) used magnetic cores to record the selections a user made. Apparently, pressing the 'B' and '7' buttons, for example, would send a current through a particular core and magnetize it. Then, as the player head scanned across the records from side to side, it would read out the state of each core and stop when it found one that was written. Seeburg called this the "tormat" module and there is more on how ti worked it here:

http://home.pacbell.net/fmillera/tormat.htm

Al those years popping spare change into jukeboxes and I never realized it used magnetic core memory...

Wayne
42  Forum 2005-2010 (read only) / Exhibition / Magnetic Core Memory for Arduino on: August 02, 2010, 10:08:55 pm
Call this more of a nostalgia project, but I've designed and documented a simple circuit that use an Arduino Nano to magnetically flip a ferrite core between 0 and 1 state and read back the result.  It's just a one bit memory, but the design is easy to scale up to larger arrays.  With a little experimentation you might be able to adapt it to read a surplus core plane, such as those sold on eBay.  For more on my project see:

  http://sites.google.com/site/wayneholder/one-bit-ferrite-core-memory

I suppose this it the kind of project that only someone who worked on computers back in the day when a "core dump" actually meant what it says, but perhaps it will be educational for the later generation, too.

Wayne
43  Forum 2005-2010 (read only) / Exhibition / Re: arduino + ultrasound parking garage senzor on: May 25, 2010, 04:46:27 pm
This code:

long microsecondsToCentimeters(long microseconds)
{
 // The speed of sound is 340 m/s or 29 microseconds per centimeter.
 // The ping travels out and back, so to find the distance of the
 // object we take half of the distance travelled.
 return microseconds / 29 / 2;
 
 if (pingPin >= 200)           //if distance is from 2meters to 30 cm green led is on
digitalWrite(green, HIGH);
digitalWrite(red, LOW);

if (pingPin <= 30)             //if distance is 30cm red led turn on, green turn off
digitalWrite(green, LOW);
digitalWrite(red, HIGH);
 
}

should be:

long microsecondsToCentimeters(long microseconds)
{
 // The speed of sound is 340 m/s or 29 microseconds per centimeter.
 // The ping travels out and back, so to find the distance of the
 // object we take half of the distance travelled.
 return microseconds / 29 / 2;
 
 if (pingPin >= 200) {          //if distance is from 2meters to 30 cm green led is on
  digitalWrite(green, HIGH);
  digitalWrite(red, LOW);
 }
 if (pingPin <= 30) {             //if distance is 30cm red led turn on, green turn off
  digitalWrite(green, LOW);
  digitalWrite(red, HIGH);
 }
}

without the {} around the if(), only the first line after the test will be based on the tested condition.

Wayne
44  Forum 2005-2010 (read only) / Exhibition / Re: Amateur satellite tracking and tuning on: February 12, 2010, 04:49:58 pm
Wow, very impressive.
45  Forum 2005-2010 (read only) / Exhibition / Re: Nixie Tube Test on: September 29, 2009, 09:59:11 am
I've updated my page on this project (see http://wayne.holder.googlepages.com/nixietest ) to include a rough schematic for the HV supply.  I'll add some mroe details as time permits.

As to the question about using high voltage on a breadboard, I'm not an expert on this, but I would caution anyone thinking of playing around with any HV power to be careful.  I haven't noticed any issues with bleed over, but I do think the weakpoint on a breadboard is the underside where the contact runs are covered over by just a layer of plastic film.  So, I'm careful not to handle the lower portion of the board (notice my fingers are only underneath the top portion of the board in the photo.)  I also make a point of discharging the HV output cap after I turn off the power so I don't inadvertently get zapped.

However, all in all, if you do want to play around with nixie tubes, I think a low current, battery based HV supply is better than using something like a voltage doubler connected to 120 VAC.  Of course, even a battery based HV supply deserves respect.  Just take a look at the people out there that build homemade "tasers" out of the flash units from disposable cameras...
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