Let's Make Robots!

Need help with rotating electrical connection!

Hey guys,


I'm doing a project and would appreciate some help. I essentially have a DC motor controlling a blade from the center. On the blade is a sensor that I need to wire to the main circuit that is below the DC motor. The problem is when the blade rotates the wires will obviously tangle.

how-to LMR meet-up

Inspired by the 2 years anniversary text on the LMR front page, I got to wondering

What do we require to make a successful LMR meet-up in real life?  

Yes I know we're spread all over the world, and anything higher than a 2% show-up rate would be a unbelievable. But what kind of physical preparations would one need? A large conference room with enough electrical outlets, loads of tables, PA-system and presentation equipment, and short distance to a bar and a cheap-ish hotel.

What else?

Serial to USB

Can i ask for your opinion...   im using the picaxe28x1 starter board..i have a serial programming cable..com-294a.jpg




can i use this?can i program my picaxe using this? 


 I saw somewhere her but forgot where. I need to make a striped stick on disk for wheels for an encoder pickup using close range IR sensors. I plan on printing them onto CD stick on labels. Any ideas?


wheels and motors

Hi all I have been trying to gear my motors down which is a real pain so I was thinking of buying a Tamiya 70097 Twin-Motor Gearbox. Does anyone recommend this or a different type. I wanna keep costs down so something nice and cheap that has 2 geared independent motors. Also I didn’t think it would be that hard to find wheels.

Barracuda WiFi Robot Controller


This is my first attempt to build a robot.  I am trying to build a Wi Fi Spy Bot robot as shown at this website: http://www.robotics-redefined.com/index.php?main_page=page&id=4

Motor drivers?

Does anyone know of high current ( 2.5 Amps per motor) motor drivers which are compatible with Picaxe AND PWM? I need to drive 2 motors.

Calculon's Arduino Serial madness, part 2

Hello LMR,

Calculon has been tinkering with his Arduino for a few months now and he likes it. He is at the point where he is trying to get his 'duino to communicate with another device. His question is: HOW?!?!?

More specifically:

1. Does he use the Serial.print command? Serial.write?

2. How does he send more than one byte at a tyme?

3. Here's an example of the required byte sequence:

     in hex: 0x8D, 0x7F
     in decimal: 141, 127

Does he just send one byte, and then another? 

upgrading from small motor

Let's say I have a motor control circuit that's too small. It could be the motor output of a Picaxe, the adafruit motorshield for arduino or a the innards of an old RC toy. The main thing is that it has two output wires, both capable of delivering positive and negative to make a motor turn both ways.

What if you want to use a bigger motor that needs more power? Below are three circuit diagrams


How to use solar panel?

I bought this the other day -  http://www.radioshack.com/product/index.jsp?productId=2062564 to use for a beam bot. Problem is, it was very cryptic with the intructions, so I'm not sure where to solder to for + or -.

If anybody has any experience with this, I'd love to hear your thoughts.