Let's Make Robots!

Digital Detection Of Black And White With IR LED And Phototransistor

I have been using a simple Black/white detection circuit with my picaxe to make a line following robot.

i wired up a circuit like the one below and programmed the Picaxe with the code below.

basicly what it did was when the IR LED/Phototransistor pair detected black it sent the number 1 to my computer and when it saw white it sent the number 0. this worked fine with the circuit wired exactly like it is below, but when i changed the Picaxe input to a different pin it just kept constantly sending 0's to my computer.

Controlling my robot with my pc using xbee

I am very new and unexperienced with wireless control using xbee and i would like to know what parts i would need to control my PICAXE robot with my computer wirelessly.

Detecting 940nm IR with 930nm phototransistor

would trying to detect a 940nm IR LED with a 930nm phototransistor be possible?

L293D only 50% power

I am trying to control 2 motors with the L293D.

when i connected the motors to the picaxe via the darlington transistor array i got full speed on both motors but when i connected the motors to the L293D i only got half the amount of power in forwards and reverse.

any ideas why this is happening?

Controlling a servo with my computer via a PICAXE

I was wondering if there is some way to control a servo's position with my computer.

for example when i click a button on my screen the servo goes to a defined position.

A circuit diagram or any code would be helpfull

Motor speed and direction control with picaxe 20x2

Hello all,

i have just recently received a picaxe 20x2, picaxe 20x2 project board, 2 geared dc motors and a bunch of ldr's!

my plan is to make a line following robot. I have worked out how to sense the line with the ldr's but cannot get the picaxe to run two motors simultaneously!!  

somebody please help!