Let's Make Robots!

Controlling 2 lcds

How would i control 2 16x2 lcds using a arduino mega? I know how to control 1 but i do not understand how to control 2 of them. Edit: i want to control them separately and i would hope i could just use the normal, non serial ones. That is i want to be able to use the liquid crystal library but that from what i can tell only controls one because when you lcd.print you are not saying to which one to print. I understand arduino mega has multiple serial lines so i guess maybe that would make it possible to use multiple serial lcds but i am not sure.

Maze robot coding

As you may know i have built a maze solving robot that does left hand on the wall currently. I have been trying to add the refining part of the code where it figures out the best path to the end without going down the dead ends (i hope you understand what i mean). Well to do that i need a string of chars and a pointer to tell where to store each char which is a turn like 'L' , 'R', 'B' or 'S'. Ok so every time i turn i need to add 1 to the pointer which i call "path_length" meaning the length of the path ie the number of turns the robot has taken.

The most useless machine ever

This is a "most useless machine" i made. I used a instructable but it was a comment by "compukidmike" that was the schematic i used. 

here is compukidmike's schematic picture thing  http://www.instructables.com/files/deriv/FCQ/XPAC/G43EFYKB/FCQXPACG43EFYKB.SMALL.jpg 

Rf links sending and interpreting

I have made a controller and trying to start programming. This is my first time playing around with rf links. I have went through gareth's walkthrough and get messages to print on my screen, thats cool but what about sending other stuff. My question is must i always send messages or can i just send integers? Also i need a bit of help on how to get the receiving code to interpret the message or integer. 
This is my maze solving robot. It uses a Arduino RBBB from wulfden.org. It has 2 30:1 micro gear motors.  The robot has 5 reflectance sensors for sensing the line. … Read more

LCD not quite working

Here is my LCD. http://www.sparkfun.com/commerce/product_info.php?products_id=709. The backlight is working, which isnt much. The problem is that it just isnt displaying the messages. The code is the code in the example and i am very certain it is right. The pins are in the same pins as the code and the example shows. So assuming that this is connected right, i think i may know some of the problem.

Could the 6v i supplied have fried it?

l293d problem

Ok so what does this mean....

 1. the four corner pins are connected to 5v

2. the 2 middle pins on each side of the chip are connect to ground

3. the pins on the outside of the ground pins are connect to the motor

4. the pins on the outside of the motor pins are connected to the inputs.


I have verified those contacts with a multimeter and they are all getting there respective connections and voltages.  

So it is connect correctly.

grrr reflectance sensors



Ok i have these on my chess robot but dont remember what i had to do to get them to work. It is the pololu digital line sensor http://www.pololu.com/catalog/product/959. Im using a arduino and 4 1.2v batteries. Here is my code. Please i forgot how to use these. 



int sensor= 4;

int x;

void setup(){ 

  pinMode (sensor, INPUT);

   digitalWrite(sensor, HIGH);





void loop(){

Multiplexing for my chess robot

Base over Apex showed to me that the "ghost piece" i was talking about could be fixed this way below. 

 Oh yeah i am doing this because my shift registers... well something happened...no im doing this.