Let's Make Robots!

Arduino: Running Programs in Parallel

I want to know if you can run two actions on the arduino at the same time while another action is going on. For example:

while the arduino is running (some action A) its also running (some action B)

What I'm trying to make is a count down timer that stops with a code. But while entering the code, the countdown runs in the background. So while its running the count down action, its also running the code entering action.

Anyone know how to do this?

Programming Serical LCD from SparkFun w/ Arduino

I working on a project right now and I need this LCD from sparkfun that's controlled by serial. I'm really confused on how to program this and get it working. All I figured out right now is that I need to update the firmware to this other guys because the current one is slow and buggy. But once I do that, does anyone know a good tutorial or know how to program one of these things?

Thanks for help guys!

Transformer Bobbin and Ferrite Cores

I'm trying to make a Switch Mode Power Supply and i have the schametic ready. But like a SMPS, the transformer must be custome made or hand spun by yourself. I need to buy a bobbin and a ferrite core but I can't seem to find any retailer to sell it to me in small numbers. All I get are big companies with quantity limits of 1000. I've searched all over google and found nothing. Anybody know a retailer that sells bobbins and ferrite cores?

2 Different Arduinos?

I wanted to buy my Arduinos from Digikey to save money and download the AVR by myself. But when I got on, there are 2 Atmega328s?


ArduinoISP Error

I'm trying to burn the arduino bootloader on an ATmega328 SMD version. I'm using my arduino Duemilanove as the ISP. But when I burn the bootloader, I get this error:

avrdude: stk500_program_enable(): protocol error, expect=0x14, resp=0x50

avrdude: initialization failed, rc=-1 Double check connections and try again, or use -F to override this check. avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

Combing Number (Not With Addition)

I'm trying to create a count down timer. But in this countdown timer you can set the time. I was wandering how to combine 2 numbers, but not by adding, just putting the together.


you press 2 and 5 to make 25 minutes.

how would you combine varriable x = 2 and y = 5 into z = 25

or if varriables are not good

how would you combine myArray[] = {2, 5} into newArray[] = {25} or myArray[] = {25} (same array)


Thanks for the help if you can!

Entering in a Password

I have a problem with my code that involves you to enter in a numbered password. Right now I have 4 buttons that all do this:



  if (inputNum == 109){    // Arduino checks which button is pressed 


     x++;                      //Increments a space value

Glitchy LCD Screen

So i have my Arduino hooked up to an 16x2 LCD at 3.3V on a breadboard.It is this LCD from spark fun. I noticed that the LCD gets really glitch when changing characters. As it start a countdown from 2 minutes. 1:59 is a bit un-seeable at the top, and 1:58 get a giant line across the top across the whole LCD and then they just dissapear. Also there are alot of random contrast changes. The Screen will sometimes be clear and the just fade a way randomly and come back. 

Arduino Scan Function

This is for another project beside the LED cube i started on. (I messed up real bad so I'm moving on). I need to get my Arduino to run a scan function. But I need it to run only once in the loop. I need it to send variables to other functions. It's kinda hard to explain, so i'll map it out a bit.

void setup(){

All this good setup stuff...



void loop(){

Dual Cell charging with MAX1555

I need t o charge this dual cell battery. So there was this great charger chip called the MAX1555. But what was sad is that it said that the MAX1555 is a single cell charger. So I was wandering, since the dual cell battery has 2 charging wires, could i buy 2 MAX1555s and hook them up to each cell, Or would that not work.