Let's Make Robots!

Interrupts and wheel encoding... a beef with...

EDIT (June, 25th 2012):

The headache just doesn't go away...

Despite the photo below now I have a tube of black heatshrink shielding the sensor. It increase the analog output, for both cases (black and white). Regardless, the behaviour remains the same as without the shield when I move unto digital pins. I've been trying to deal with debouncing for the past couple of days with no luck.

// Playing with encoder digital readings


const int sensorPin = 7;


int lastColor;

int currentColor;

int count;

Inverse kinematics

Been trying to understand inverse kinematics for programming my quadruped Crap-Crab. I started out by reading Wikipedia's version, which lost me completely (WTF?). But then I found the explanation by this guy and it turns out, as I thought to begin with, that it's simply a matter of applied trigonometry.

Here is exactly what I need in a nutshell:

Simple Audio Preamp

i found an easy to make audio preamp that i intend to use to measure a sound with an ADC input on my arduino. i want my robot to respond to me clapping and start a drumming sequence. I may have to use some aditional circuitry to turn the output to a simple high pulse when the sound goes above a certain level, this way i can use one of the arduino interrupt pins to start the sequence at any time. heres the link:


here is someone who has used it with an avr chip

RoboPi - the most powerful Robot controller for the Raspberry Pi (adds 8 core co-processor)

RoboPi stacked on a Raspberry Pi

Mikronauts RoboPi adds an eight-core 32-bit microcontroller running at 100Mhz to the Raspberry Pi in order to off-load hard real time I/O and allow more precise timing than Linux running on the Pi allows.

RoboPi Features

OK, I have just given up making a balancing robot. Ever.

Making a balancing robot - or even dreaming of making one just lost it's appeal.. because I will never make anything like this.,

Help me connect Xbee to Picaxe!

OK, so I’m going to make a remote control to my next robot. I want to connect a picaxe 28x1 to a Xbee and I have ben trying to find
some good examples but with limited success.

As the Picaxe operates at 5V, whilst the Xbee operates at 3.3V I understand that the signal from the picaxe has to be regulated. (not just the input voltage to drive the device).
Of Cause I could run both the picaxe and the Xbee at 3.3V, but that would just screw with everything else I'm gonna connect to it.

Speech Recognition with BitVoicer and Arduino

The main goal of this project was to test the speech recognition performance of BitVoicer (http://www.bitsophia.com/BitVoicer.aspx). For this purpose, I designed a simple led control sketch which I integrated with BitVoicer. Of course you can do anything you want once you have received the commands from Bitvoicer, but to keep things simple, I thought a led test would do just fine.

Hybrid H bridge single relay configuration

So I have been brainstorming H-bridge designs for a 5V motor with 5A stall current.  I want max speed from the motor off 4xAA batteries, so I am considering using a high side relay vs a high side transistor.  I would like the H bridge to:

Android phone as a controller

Hello there :)

I'm on the edge of purchasing an android phone. Looking at specifications around i thought: "Hey but this is the perfect controller for a robot!!" It has an incredible inventory of useful stuff: gps, compass for navigation, wifi, bluetooth and cellular for communication, huge screens for UI, speaker for talking, plenty of cpu, camera, easily programmable, and so on, all packed in a small package, all low power! And all for as less as $200! What do you want more ??

There's only a drawback: there's no simple way to phisically connect a device to peripherals :(


In a reply to this post: http://letsmakerobots.com/node/31641 I have exposed one of my software problems that I encountered on one of my robots. I am re-posting this separately with some added info:

How to connect a light dependent resistor to a picaxe 28X1


I recently go a light dependent resistor

and i cant seem to figure out how to connect it to my picaxe28X1, would anybody here know how ???

Any help would be apreciated !!!!!

Robot tank tracks

I thought I'd post some info about tank tracks that I've come across. Please feel free to add to it.


Tamiya Track Kit


Solarbotic/Pololu Tank Treads and Cogs

Arduino vs Picaxe

Should I go for Arduino or Picaxe for my next robot?

(EDIT: Please note that this is a very old post, things have changed :)

LMR ROS platform

What is ROS

Here is a list of robots running ROS

I think it would be great if we could make a minimalistic, cheap, easy reproducable, simple robot running on ROS. Something to get people started with ROS, as the isolated and primary goal.

If any one out there is up for that challenge, let me know, and I'll support by such things as getting it in the menus of LMR, perhaps make videos about it, and get it on the official ROS pages, maybe turn it into a "start here" tutorial etc.

Docking, Beacons and Triangulation (Open Discussion)

I just wanted to open a discussion on getting a robot from A to B using triangulation. Really, I might just be looking for a math class here...