Welcome to Arduino!

General Arduino beginner instructions here:
http://arduino.cc/en/Guide/HomePage

Guide to the Arduino Nano here:
http://arduino.cc/en/Guide/ArduinoNano

I recently built my own serial to USB cable that does not have DTR line.

Here's the timing that works for me:
1. Press and hold down the reset button
2. Press control-U in the IDE to start compile and upload
3. Continue holding the reset button until you see the message at the bottom of the IDE showing "Binary sketch size..."
4. When you see that message, release the reset button.

This works great for me.  Good luck!

Ah, you're right digimike.  I didn't catch that. Thx.

analogWrite(2,255) will light up DIGITAL pin 2 at full brightness (continous on).  analogWrite is confusing because it ALWAYS writes to a DIGITAL pin!

http://arduino.cc/en/Reference/AnalogWrite

analogRead(2) works as expected, reading analog pin 2 , while digitalRead(2) reads digital pin 2 (provided you call pinMode(2,INPUT) first.)

[edit]To turn on the LED on analog pin 2, as Osgeld mentioned, you need to refer to it as digital pin 16:
pinMode(16,OUTPUT);
digitalWrite(16,HIGH);[/edit]

Wow! that was a fast reply!
Are there screws behind the stickers or something? Or when you said "separated the plastic" you meant break it?   Thanks again!

Can someone tell me the name of the connector used by the GPS-500 unit so I can order it from Digi-Key? Even better would be a cable (such as for a cellphone) with that jack and I would just hack the other end of that cable.

Thanks in advance!

http://www.flickr.com/photos/imager/4383334403/

I'm able to record and playback IR codes using Ken Shiffiff's IR library:
http://www.arcfn.com/2009/08/multi-protocol-infrared-remote-library.html

However, my Sony DVD player is not responding to the code sent by my IR LED. :-(
I can see that the IR LED is blinking using a digital camera.

I've tried these two IR LEDs:
model 276-143:
http://www.radioshack.com/product/index.jsp?productId=2062565

model 276-142:
http://www.radioshack.com/product/index.jsp?productId=2049723

Has anyone successfully using this library using these IR LEDs?
Which IR LED I should use instead?  Thanks!

Gardner, I will look into discrete MOSFET circuits, but I'm beginning to think that maybe motor driver board is the best route for beginners like me.

Thank you for all your pointers.
=Hari=

Increasing the voltage worked, but the SN754110 got hot very quickly.
The L298 is not MOSFET, would it still work? it's rated at 4A.

gardner, could you recommend a MOSFET based motor controller?

Grumpy_Mike, the power supply is four 2500mAh rechargable AA batteries.  There is no regulator, the SN754110 stayed cool.  The batteries do not get hot.  Arduino drives the +5 and control pins of the bridge and nothing warm there either.

Zoomkat, you maybe onto something... I measured the voltage across the motor, last night and it was only 2.9V!     I'll try increasing the supply voltage tonight.

Thanks for the replies guys!

I'm trying to have bi-directional control over two electric screw driver motors.  They're 4.8V 1A each.  I was able to run it directly or turn it on/off using a TIP120 Darlington Transistor.

However, controlling the motor using the SN754410 bridge barely moved the motor.  

I know there are many Motor Driver boards out there, but they are all more than $20.  The one for $20 is based on the same the L298 (granted it has serial control, but I'm perfectly happy to control the motors using a few digital Arduino ports.)

The spec for L298 says it can drive up to 4A.

Would purchasing the $3 L298N Dual Full-Bridge and the  $3 matching breakout board solve my problem?  Or do I need something beefier?

Thank you.

Yes, in the original circuit and sketch, digits are displayed in proper sequence.
There was an error in original dataspecs, so maybe you're running into something similar with your display? I don't know.

Ah...
If you take a look at RefreshDisplay(), you will find two lines similar to this:
digitalWrite(digit0 + digitPosition, LOW);  // Turn off previous digit

Each digit is turned on one at a time, so the above line turn off the previously on digit, adjust the segments for the next digit, and then turn on that next digit.

You should be able to adjust the calculation of the first parameter instead of re-wiring the circuit.  Maybe something like this:
1. Change digit0 from 10 to 13
2. digitalWrite(digit0 - digitPosition, LOW);  // Turn off previous digit
3. digitalWrite(digit0 - digitPosition, HIGH);

Testato,
If I understand you correctly, it is probably simplest to adjust the wiring rather than the code.  Take a look at Arduino pins 10,11,12,13.  Those corresponds to the digits.
Say right now you have it wired like this:

Arduino	Display
10	P
11	Q
12	R
13	S

You have complete control as to which digit value correspond to which display digit.  What if you re-wire it like this?

Arduino	Display
13	P
12	Q
11	R
10	S

Good luck!

Thank you!
The display works perfectly now!

Awesome! Glad to be able to help.

One more question: how would I go about getting the colon to stay lit all the time?

I don't know.  Sorry...   :-[