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1  Using Arduino / Installation & Troubleshooting / Re: Pro Mini to USB Adapter on: January 31, 2011, 10:46:45 am
One thing I had wrong.. FTDI cable green is RTS not DTR ... From the specs on the usb adapter, it looks like DTR should trigger the auto reset, but it does not
2  Using Arduino / Installation & Troubleshooting / Pro Mini to USB Adapter on: January 31, 2011, 10:35:23 am
I have a pro mini which I'm trying to connect to the USB Adaptor break out board.  I'm having problems programming (works fine with a FTDI cable connected to the pin header on the pro mini at the end of the board, but I want to use the USB breakout) the board.  I think the problem is how I am connecting the RESET pin on the pro mini to the board.  Since on the breakout cable, the green (DTR) wire looks to be the one to drive the reset to the header, I've connected the DTR line on the breakout board to RST on the pro mini.  Can't seem to get that to work.  I've crawled through the site looking for something to help, but i've been unsuccessful.  Any suggestions.
3  Using Arduino / Project Guidance / Re: Gas powered soldering irons?? on: January 31, 2011, 09:13:12 am
I use one of the Home Depot butane irons for quick repairs at the RC field and at the race track for the car (i've never had to use it for my car, but have used it dozens of times on others (i keep a bit of shrink wrap with me in my kit as well).  Works well for quick things, but even with my limited electronics skills i would not use it for any kind of primary heavy duty usage.,
4  Using Arduino / Sensors / Analog Sensor on: January 28, 2011, 08:42:30 am
I have a sensor (analog output 0-1v - its a ignition advance output from a ECU,  the decimal voltage represents the advance (eg 0= 0 degrees, 1 = 100 degrees).  I'm trying to simulate this with a voltage divider (to take 5V to 1V and a pot to give me the the ability to change the voltage between 0 and 1
I have the divider with a 100ohm and a 22ohm (did not have a 25ohm,  so my range is really 0 to 0.9V).    Since I need pretty fine granularity, I want 1v to be 1023 from the Analog input,  do I have to change the reference voltage to be 1v as opposed to the default 5v  (right now, .9v  approximagely 180 (varies somewhat between 180 and 185, which I'm taking as the tollerance of the resistors and the pot... 

5  Using Arduino / Project Guidance / Source for ATmega328P on: January 27, 2011, 11:35:54 am
Looking for a place to source a few ATmega328P TQFP package processors
6  Using Arduino / Networking, Protocols, and Devices / Re: Android tablet USB master to Arduino on: January 27, 2011, 11:06:17 am
The tablet and the Arduino are both USB Slaves.. 
7  Using Arduino / Networking, Protocols, and Devices / Re: RS 232 communication with Serial1 on MEGA 2560 on: January 27, 2011, 11:05:21 am
Are you trying to drive the DB9 directly from the MEGA pins?   If so, you are trying to use TTL to talk RS232, which can't be done.  I believe you need something like a MAX232 to convert TTL to RS232.

Try this  connect TX2-RX3 and RX2 to TX3 and see what you get on Serial2.  
8  Forum 2005-2010 (read only) / Syntax & Programs / Re: 7 segment reed switch speedometer help on: August 26, 2010, 02:55:10 pm
If you are using a switch, why are you using an analog input, each time the magnet passes the switch, you should get a 1 pulse.  Could you not tie this to an interrupt with a rising trigger, and use a digital input and a couter that increases in the interrupt handler.  Then in the loop() you can just sample the counter value every X ms and do your conversion from Rotation to MPH.   Look at the tachometer code example in this forum.  
9  Forum 2005-2010 (read only) / Syntax & Programs / Re: Dyno controller, searching for inputs? on: August 26, 2010, 02:43:35 pm
Why use a hall effect sensor at all.  Depending on the engine, and ignition system, you could
a) connect to the coil like a display tach, count the pulses and do the math (there is a sample interrupt driven counter on this forum, just search for tachometer)
b) most CDI boxes have a tach out signal, which is usually a 12v square wave, which you should be able to reduce to 5v with either a simple voltage divider, or a regulator (I'm trying a regulator for the Data Acquisition system i'm building using the Mega board (more inputs, and more memory)
c) use a magnetic switch, with a magnet on the flywheel, you then feed the switch cycle into the interrupt handler, count  and display RPM every X ms (I'm planning on using 250ms interval for display, but you could go more granular

Here is some code (taken frm the referenced post to the forum, and made into an object).  Note, I still have to adjust the "pulses per rotation" for my 6Cyl motor, but if you use a mag switch, then you have 1 pulse per rotation.

// Tachometer hooked up to interrupt 0  Digital Pin 2 on All boards.
unsigned long tachCount;  // Global scoped within the object.  

// Interupt function.  Can't be part of the object.
void tachPulse()

      tachCount = 0;
      _time = millis();

void Tachometer::tachprocess(unsigned long time)
      int rpm;
      unsigned long deltat;
if ( (millis()-_time >= 100) )
    // rpm = number of interrupts counted in 100ms
    //  *10 to make per second
    //  *60 to make per minute
    //  /2 for 2 pulses per rotation (4 cylinder)
    //  /10 for some reason???
    rpm = (((tachCount*10)*60)/2)/10;
    //Do things with the RPM value here (update display etc)...

    tachCount = 0;
    _time = millis();


void Tachometer::tachSetup(unsigned long time){
      _time = millis();
      tachCount = 0;
10  Forum 2005-2010 (read only) / Syntax & Programs / Re: Using MAKE instead of the IDE on: August 26, 2010, 07:48:36 am
Thanks for the pointer.   This helped a lot,   but I'm not sure what values to put in for MCU and F_CPU.  I'm using a MEGA board so I think MCU=atmega1280 is correct, but what about the F_CPU make variable.  I think that a speed of 16000000 is correct for 16Mhz per the datasheed for the Mega.
11  Forum 2005-2010 (read only) / Syntax & Programs / Using MAKE instead of the IDE on: August 25, 2010, 04:11:49 pm
Is there a tutorial or page that documents using Make (I know how to build makefiles etc), in lieu of the IDE.   I'd still like to use the bootloader functions to download sketches from the makefile, but if anyone has a sample makefile to share it would be appreciated
12  Forum 2005-2010 (read only) / Interfacing / Re: Xbee dilema on: October 25, 2010, 03:28:12 pm
I'm not changing any of the parms.. i;m just reading and then writing them back out to the device.

I'm just trying to get the single device to respond to AT commands from a terminal, not even trying to send data between the devices.

Both are XB24 (from xctu modem configuration) function set Xbee 802.15.4 version 10E8

Nothing has been changed, these are exactly what they were configured to out of the box.

from my reading.  if i send +++ to the single device it should respond with OK
sending ATID should give the id that it is configured.

I get nothing from the device, but clearly xctu is doing this when testing from the test/query button on the PC settings since its getting the data back to identify the device.
13  Forum 2005-2010 (read only) / Interfacing / Xbee dilema on: October 25, 2010, 02:36:56 pm
I have 2 XBee modules, and the sparkfun regulated breakout board, and the USB breakout board so i can attach to a computer.  The following happens on both boards when attached to the compute

i am able to
a) test with XCTU and it reads the device fine
b) i can read the device configuration, and write it as well.

in both cases the TX and RX leds on the breakout board blink.

However, from the terminal window, no matter what I try I can't get anything back (sending +++ should give me OK, but I get nothing, same happens with hyperterm or any other terminal emulator).  Range test in loop back mode also does not work, i get receive timeout errors, and the RSSI led never lights up.  I've put the latest firmware from Digi

These are XBee24  Version 10E8 devices.

Any ideas.

I;ve also tried to interface with a sketch, and still get nothing from the device, the
14  Forum 2005-2010 (read only) / Interfacing / Re: Simple Interrupt on: August 26, 2010, 06:49:58 pm
I changed my circuit to not use the +5v output on the board, powering the switch with 4 AA bateries, and now with CHANGE as the trigger,  things seem to work better.
15  Forum 2005-2010 (read only) / Interfacing / Re: Simple Interrupt on: August 26, 2010, 06:43:02 pm
When you say "configure the pin a little bit"  what do you mean.  I've tried writing HIGH to it after configuring it to be an input pin, which as far as I can tell should enable the internal pullup resistor.  I changed the interrupt to trigger on CHANGE, which should mean that the button becomes low, and changes the state.
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