Let's Make Robots!

USB as power source for small robot

I want to use my PC usb port to power a small robot
It contains a buzzer and two solar motors

I have measured that the robobt drain a maximum of 250mA 
Could be there any issue for my motherboard doing this think?

I am very scaryed about to fry the mobo :O

what hapne to usb hub in case of abnormal current drain / short circuit? 

Is there a robust overcurent protection in modern 2.0 usb hub?

Creating a Microcontroller from Scratch

So i want to make a basic first robot and i understand what to do with an already built microcontroller but as a challenge i actually want to build a microcontroller from SCRATCH.

Yes i understand that it's a tough thing to start off with but my plan is to understand how everything works by actually doing it. I'm currently working towards an electrical engineering degree so i know basic terminology or i can look up anything new.

Servo coding (solved)

It is working now, thanks to everyone who helped me out!!!



I am trying to make my servo work,but if I start my arduino, with code and servo attached, it just goes to one position and stays there twitching. Can someone help me?

second try

AI Challenge anybody ?

I have found aichallenge.org like two weeks ago and I could not stop myself to play there.

At first I was thinking at swarm robotics but software only. In their challenge you will lose if you choose this way but you can use the tools they offer to build your swarm robotics farm, especially if you know python to customize the framework. The robots can be writted in different programming languages - I use C++.

LMR Robot Building Workshop at Maker Faire NYC!

Ta Daa!

Thanks to the kind sponsorship of our friends at  we will be able to offer a robot building workshop at Maker Faire in New York this year!

 Details will follow, but Picaxe will supply the PICAXE-08 Motor Driver Board, along with some funding.

I2C servo controller schematic and layout

Hello LMRians!


So after half a day of work I came up with this board design for an I2C servo controller (the schematic was done in 10 mins..). So could you please check if this design is going to work as it's the first board I've ever designed?


The schematic:


And the board layout without the GND planes:


With the GND planes:

Some software help with Bluetooth modules

I got tired of operating "blind" when working with those inexpensive serial bluetooth modules, so I wrote a utility that helps with testing them as well as reprogramming the name/pin/baud.  

Simple Map robot



I have arduino duemilanove, ultrasonic sensor , geared motors with wheels. I wanted to make a room mapping/ navigating robot to go from one place to other.

 Even if it doesnt learn the environment in real time ,is allright. I just want it to store a simple map of square room and go from one square tile to the other.


Please guide me.




Does anyone have decent code for an HTML5 (canvas) sonar sweep?

Currently, I use a Google Chart to image my sonar sweep onto the web control page ..... once the scan has completed...  yeah...Too little too late.


I'm going to embark on coding the HTML5/Jscript  tonight if nothing exists that I can pilfer.. .er ... borrow.

What I'm looking for is a scan that takes "angle,distance"  pairs, and maps them onto a HTML5 canvas (of course removing previous one for that relative angle) and then doing a "lineto(x,y)" from the previous one. 


Help with Beaglebone Black balancing robot

Hello everyone, I want to start by saying this question post might become long and I hope you guys hang on and are able to help me. So here we go :)

First of all the robot is barely able to balance. Here is a video of the robot trying to balance. The problem seems to be that the robot is not able to reach the setpoint fast enough. This is a speculation so you guys give me your ideas on what the problem is also.

IR and ultrasound based positioning beacons

I have this idea for a positioning system based on IR+ultrasound beacons. It is very simple, and I'm surprised that I can't find anything like that already in use. I guess there are some problems that I can't see, so I wanted to ask you to point the flaws in my idea before I invest time and materials into chasing a pipe dream.

The goal is to get an accurate position of a robot inside a room that is decorated with some additional beacons. The positions of the beacons are known to the robot, so that it can position itself relative to them.

Capacitors for smoothing servo current surges

I've built what I thought was a nice clean approach to the oft-recommended practice of parking a 470uf cap on the power lines to my servos. I have 6V coming from my voltage regulator to the postive/negative bus strips on a small PCB. I've pulled a positive and negative wire off of the bus for each servo (3 servos total) and put a capacitor across each pair of wires. One servo should then connect to each pair of wires.

Video transmission

Hi everyone,

I'm quite new in all of this, but i want to build a robot able to transmit video, and possibly sound. I've got a common webcam and I want to make it wire less, but I don't know how to do it.

I would apreciate any help from you lot.


Ways of communicating with a PC

A nice inspiration to control robots / communicate PC <-> Robot

Boosting Speakers with the Lm386

Hey All,

So I'm integrating the SpeakJet into my next project, and using the LM386 to try to boost the speakers. Unfortunately, the package didn't include any circuit (or information whatsoever, really) and Radio Shack has discontinued their databooks. So I went to the go-to info tool, THE GOOGLE! I've seen this circuit all over the place:


A few questions about this circuit:

1. Is the .05uf cap and 10 resistor recessary if it's just going to ground?