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6541  Development / Other Hardware Development / Re: ATMEL Mega1284P evaluation board avalible on: May 14, 2011, 04:24:46 am
Quote
What would you say to an Uno compatible board with shield compatibility, 1284P processor, added RS232 drive capability, and additiona port pins to take advantage of the other port the 1284 offers?
I'd say you've had this on the cards for a while smiley I'd also say it's a good idea.

Let us know if you want people to peer review of the schematic.

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Rob
 
6542  Using Arduino / General Electronics / Re: 10K pot without stop on: May 14, 2011, 02:07:50 am
That sounds like a plan, similar to what Crossroads was getting at I think.

Dual pots are common but I've never had a good look to see if it's practical to separate them and remount out of phase. If so I'd be inclined to use 180 degrees each with a little hysteresis at the crossover points.

Getting back to using rotary switches, the OP said he doesn't want detentes but with most of those switches you can remove the ball bearing and make them smooth.

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Rob
6543  Using Arduino / General Electronics / Re: 10K pot without stop on: May 14, 2011, 01:45:51 am
Like I said, 27 degree dead band.

In the digikey catalogue they say 347 degrees, but if you look at the graph linked to by digikey (http://media.digikey.com/pdf/Data%20Sheets/Panasonic%20Resistors%20Thermistors%20PDFs/EVWAE4001B14.pdf) it doesn't start ramping up untill just over 13 degrees then stops at 347.

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Rob
6544  Using Arduino / Networking, Protocols, and Devices / Re: Decoding NRZ.... A possessed At mega ?? on: May 13, 2011, 07:25:51 pm
If you just need to reproduce the signal I see three options

a) forget the Arduino, just use a wire
b) if you don't have to do anything else then don't bother with timers and interrupts, OUT_PORT_PIN = IN_PORT_PIN
c) if you do have other processing to do then attachInterrupt (serialPortPin, CHANGE); in the ISR, OUT_PORT_PIN = IN_PORT_PIN

There may be some jitter because of the millis() interrupt but that will be the case with any approach I think unless you disable it.
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Rob
6545  Community / Exhibition / Gallery / Re: Core memory shield on: May 13, 2011, 06:35:30 pm
I have a diode-logic nixie-tube calculator somewhere, it has a 32x32 (I think) core module in the centre of a 1000 diodes. It's a clear plastic module that was obviously a product you bought in those days.

All the diodes are mounted vertically like a field of young mangrove roots, God know how they debugged the board.

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Rob
6546  Using Arduino / General Electronics / Re: 10K pot without stop on: May 13, 2011, 06:29:44 pm
@Crossroads
I've not seen them before, filed for future use. You notice though that they have about 27 degrees of dead band, seems rather a lot for something that's specifically designed for this use.

@neema_t
Thanks, also filed for future use.  I love the concentric ones, I just have to think of an application now smiley

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Rob
6547  Using Arduino / Project Guidance / Re: hardware used to test continuity of a 50 pin connector? on: May 13, 2011, 09:14:03 am
You put a 1 in the driver shift regs and have 50 bits of MUX for the input, say using 4067s or 4051s. Then

Code:
digitalWrite(shiftRegDataPin, HIGH);  // set a 1 bit for shift regs
digitalWrite(shiftRegClockPin, HIGH); // clock it out
digitalWrite(shiftRegClockPin, LOW);
digitalWrite(shiftRegDataPin, LOW);  // set a 0 bit for shift regs

for (int i = 0; i < 50; i++) {

    setMuxAddr (i - 1); // have to handle special case when i == 0
    if (digitalRead (muxPin) == HIGH)
      error();
    setMuxAddr (i);   // you'll have to write a func to do this
    if (digitalRead (muxPin) == LOW)
      error();
    setMuxAddr (i + 1); // have to handle special case when i == 49
    if (digitalRead (muxPin) == HIGH)
      error();

digitalWrite(shiftRegClockPin, HIGH); // move the 1 bit to the next wire
digitalWrite(shiftRegClockPin, LOW);
   
}

That's the general idea.

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Rob
6548  Using Arduino / Networking, Protocols, and Devices / Re: Problems with serial port (RS232) sensor on: May 13, 2011, 09:04:09 am
Have you verified that the MAX232 output is good?

What do you get if you just Serial.print() the sensor data?

When you get good data from Serial.print then you can start blaming the Xbees and maybe drop the data rate and see if that works.
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Rob
6549  Using Arduino / General Electronics / Re: 10K pot without stop on: May 13, 2011, 08:20:10 am
The top one looks good to me because it has a mounting thread/nut. Unfortunately it looks like it's been discontinued by Panasonic.

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Rob
 
6550  Using Arduino / Microcontrollers / Re: Bootloader for a 1284P @ 16MHz - problems :-( on: May 13, 2011, 05:40:09 am
That sounds like the error James was getting on that thread, apparently though the loader still worked despite the error.

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Rob
6551  Using Arduino / Displays / Re: 4D LABS μLCD-32PT(SGC) 3.2” Serial LCD Display Module Arduino Library on: May 13, 2011, 04:03:11 am
OK I see that, I guess that is affectively the same thing, especially if they implement the contrast adjust by dimming the back light which they may do.

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Rob
6552  Using Arduino / Microcontrollers / Re: Bootloader for a 1284P @ 16MHz - problems :-( on: May 13, 2011, 03:55:34 am
Have a look at this thread

http://arduino.cc/forum/index.php/topic,58014.msg424488.html#msg424488

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Rob

6553  Using Arduino / Displays / Re: 4D LABS μLCD-32PT(SGC) 3.2” Serial LCD Display Module Arduino Library on: May 13, 2011, 03:09:19 am
@avenue
I grabbed the code form your site and am having a look.

IIRC there's no way to dim the backlight, is that the case?

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Rob
6554  Using Arduino / General Electronics / Re: 10K pot without stop on: May 13, 2011, 01:47:08 am
You can fudge an encoder with a rotary switch but probably can't tell direction, just that it was turned. They do give nice detents on the stops though.

Actually you can tell direction I think if you use a 6p2t switch and wire it correctly you would get values of 0, 1, 2 and 3 and the software could tell which direction from that. (just thinking out aloud, it may not work as I said but you might be able to figure the direction out with some thought.)

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Rob
6555  Using Arduino / Motors, Mechanics, and Power / Re: Where can I buy arduino friendly solenoid valves? on: May 13, 2011, 01:18:54 am
There are plenty of shops that sell solenoid valves, most hardware/irrigation stores for example. But one big question is

"Do you have pressure?"

Because most solenoid valves need the water pressure to open.

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Rob
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