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61  Using Arduino / Programming Questions / Re: Timing and speed issues with pin change interrupt based routines - Arduino slow? on: April 26, 2012, 08:10:25 pm
could you just have a tight loop that reads all 12 bits and does a table lookup or hash function to get the 4 output bits?  Don't worry about changes - just translate 12 bits to 4.
62  Using Arduino / Project Guidance / Re: Make a RC car run a whole race track pre-programmed on: April 13, 2012, 07:31:02 am
Easiest approach to rc from arduino to car might be to get a cheap car and take apart the transmitter box to hook the arduino in. I did this with an rc plane and was able to control it easily. I'm sure a car would be too.

I was actually trying to fly the plane on a programmed path with feedback via a webcam watching for it - very little luck with that.
63  Using Arduino / Interfacing w/ Software on the Computer / Re: Plug 'n Play Webfirmata: Control your Arduino without any programming on: April 08, 2012, 09:50:39 pm
It all runs on one windows box with chrome - right? I just add the labscript package?

I can see it being useful for some hardware poking - i'll try it out.
64  Using Arduino / Sensors / Re: Using range finder to scope territory on: April 01, 2012, 02:10:34 pm
I run a wall follower with two sensors. 1 in front and 1 to the side.
65  Development / Other Software Development / Re: [SOLVED]Passing extra options to avrdude on: March 24, 2012, 12:42:33 pm
So how did you do it?
66  Using Arduino / General Electronics / Re: What's a good thickness of copper clad to use? on: March 12, 2012, 08:58:50 pm
I believe standard copper clad is .035 "

I imagine yours would etch more easily though.

If you have the space to make your traces wider maybe thinner is better!
67  Using Arduino / Programming Questions / Re: Single pin Port Manipulation on: February 25, 2012, 12:45:21 pm
So, I wrote a short blink sketch. I used #define to set the hex values, now using them in the program is easy.
This compiles to 846 bytes (IDE 0023) but using digitalWrite() to do the same thing compiles to 1034 bytes. After seeing this, it's hard to think of a good reason to use digitalWrite anymore smiley-lol
#define D13high  | 0x20;  //hex code to write Digital Pin 13 HIGH
#define D13low & 0xDF;  //hex code to write Digital Pin 13 LOW

void setup()
  pinMode(13, OUTPUT);
void loop()
  for(int i = 0; i < 10; i++)
    PORTB = PORTB D13high;  //set Digital 13 HIGH
    PORTB = PORTB D13low;   //set Digital 13 LOW
Until you want to change the pin you're using!
68  Using Arduino / Programming Questions / Re: Blink Without Delay Revisited on: February 25, 2012, 12:42:11 pm
I like your code - thanks for sharing.
69  Using Arduino / General Electronics / Re: generating a two stage signal. on: February 10, 2012, 01:22:50 pm
ok, way better idea.  The single digital pin will drive both outputs either high or low but, if I tri-state the pin, resistors will pull the outputs to the reset state.  much simpler and i can control the sequencing in software.
70  Using Arduino / Interfacing w/ Software on the Computer / Re: Connection using pyserial doesn't work properly on: February 10, 2012, 01:02:23 pm
I can't speak to the linux serial open differences but this does sPeak to them.

71  Using Arduino / Interfacing w/ Software on the Computer / Re: Connection using pyserial doesn't work properly on: February 10, 2012, 10:48:39 am
I wonder if you should try some sort of ack/nack/timeout protocol like when the arduino wakes up it sends a syn character and waits for an ack in return. If it doesn't get one after (say) 500 ms it tries again. Once it gets an acknowledgement hack you can go to whatever protocol you had planned. Your python script could reset the arduino when it starts and, if it doesn't see a syn within some time, reset it agaIn.

There's probably some mOre robust variant of this but you get the idea.
72  Using Arduino / General Electronics / Re: generating a two stage signal. on: February 09, 2012, 07:23:13 pm
@lefty, yeah, nothing left, I'm even using the xtal pins.  The avr just has a bit part in the circuit but its i/o pins are all spoken for.

@MarkT and tjb: I don't *think* it's a single 555 or monostable because I need one output to go high first when my input goes high and stay high longer when it goes low.

So far I'm looking at the following when the input on the left goes high, the lower right output (/clear) will be slower to go high because of charging its cap thru the 100k rx.  when my input drops, the top output will stay high longer because it has to discharge its cap through a 1M vs the 100k.  I think this would work but it's a lot of pieces.
73  Using Arduino / General Electronics / generating a two stage signal. on: February 09, 2012, 06:04:52 pm
I'm short an output pin to control an outside circuit and I need a simple way to control two outputs from 1 pin.

when my input signal goes low to high I want output A to go high, then 100-200 ns later, output B to go high.

when my signal goes high to low I want output B to go low then 100-200 ns later output A to go low.

The effect is that both A and B track my input but I always get A=high and B=low briefly between transitions.  (I'm driving control pins on another processor between two stable states 11 and 00 with a guaranteed 10 in the middle which is a reset).
74  Community / Exhibition / Gallery / Quad-core assymetrical multi-processor on: February 04, 2012, 04:06:05 pm

The RBBB on the bottom right is running a modified version of arduinoisp to load code into the CDP1802 "olduino" on the left.  The diecimilia top right is back-channel serial debugging info from the arduinoisp.  The breadboard processor in the middle is actually not connected to the others, it just happened to be on the breadboard and i didn't want to screw it up.  I just thought the whole thing was funny enough to share.
75  Using Arduino / Microcontrollers / Re: Arduino UNO 3 Digital I/O count on: February 04, 2012, 08:43:19 am
Have a look at PORTB and direct port manipulation. This may be exactly what you need.
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