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Tuesday, April 16, 2013

Adventures with Small Computers

I've succumbed to the lure of the tiny computers and microprocessors.  This weekend I was playing with the Arduino that I bought (supposedly) for Billy.   You see, I have a little microprocessor-based keyer in my ten meter beacon rig (Demaw's "Lil'Slugger") .   It works fine once you get the desired Morse sequence into it, but getting that done is difficult and frustrating for someone (like me) unaccustomed to an iambic keyer.   So I was thinking that this would be easier just to replace the keyer with  an Arduino.  I was right.    With some help and advice from Billy, I got the Arduino going, and got the little LED blinking.   Then I took some code from Mark K6HX, modified it for my call-sign, and loaded it into the Arduino.  No problem at all.  Kind of fun.  And it opens your eyes to all the possible applications of this little board. 
Unfortunately, in the course of fooling around with the interface between the board and my rig I think I did damage to my Arduino.  I managed to blow out the blinking (pin 13) LED on the board.  I could live without that, but now the ICs get very hot (especially the little surface mount chip just below the 16 MHz crystal).   Anyone hope of fixing this?  (I've already ordered a replacement board,  but I feel guilty about this.)
Here's a good article describing the pros and cons of Arduino, Raspberry Pi and Beagle Bone:

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  1. That chip which is getting hot is an LM358. It's involved with determining the power source you have plugged into the Arduino. http://arduino.cc/forum/index.php?topic=128466.0

    If you can't save the board you can still save the Atmega328 microcontroler. Just pop it into the new board to program it. When that is done take it out and all you need are a 16Mhz Crystal and two capacitors or a ceramic resonator. Then you can build the chip into whatever project you want without having to buy a whole Arduino. It could even be a permanent part of your keyer!

    Don't do that with the chips from both Arduinos though. You need to keep one. That way you can buy more Atmega 328s. This is way less expensive then buying more Arduinos, I get mine for about $3 including the clock parts from Mouser.

    When you buy a fresh 328 chip, it needs a bootloader programmed onto it before the Arduino software can talk to it like it would a normal Arduino. For that you need a whole Arduino and a breadboard. See the bottom part of this page for how to do this with only one Arduino. http://arduino.cc/en/Tutorial/ArduinoISP

    Good luck and enjoy!

  2. I should have sent you this link instead of that second one, sorry!


    I'm not sure what the point of that middle section 'upload using an arduino board' is though. You could achieve the same thing by just plugging the chip back into the Arduino and skipping the breadboard!

  3. Oh, almost forgot. One more thing then I will stop clogging up your comment section.

    If you do decide to get some more chips watch out for the difference between Atmega328 and Atmega328p. The p ones will be easier to work with and use less power. The non-p ones are ok too but you have to go into some configuration files inside the Arduino software and change some things before you can burn the bootloader. Then you have to go in and change it back. I found that one out the hard way!

  4. Very cool, thanks! I have also succumbed to these wonders and I recently bought a Raspberry Pi.

    Please check my video at:

    It´s in Portuguese, though...


  5. 1. For a REALLY inexpensive and small variant, try Modern Device's 'RBBB' (Really Bare Bones Board) Arduino clone. $13 for a kit (maybe 30 minutes to assemble). These are great for testing, but are cheap enough to build into a project: http://shop.moderndevice.com/products/rbbb-kit

    2. For the REALLY REALLY inexpensive version - when you no longer need the separate board - the Minimalist Arduino (Controller IC, Clock, LM7805, couple resistors/caps) -
    (can sub an ATMEGA168 for the 368).
    You'll have to burn the bootloader some other way to get started, though, but afterwards, the Serial Pins will work.

    Mike Yancey, KM5Z
    Dallas, Texas

  6. Microprocessors are sensitive and can easily break. Always make sure to keep it safe.


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