Let's Make Robots!

Recommendations for steering

I'm building a yard bot. The initial blog is posted for my Yard Gnome already.

This robot will steer like a car, with one drive motor pushing two rear wheels, and a two-wheeled steering mechanism up front.

I'm looking for recommendation for how to automate steering on this thing.

Is there an affordable servo that is strong enough?

Should I build my own servo?

Radio mast navigator - idea :)

Hi, just got this idea, and thought perhaps it would interest one of the clever guys out there. Hope is that a vendor will take this up, after a couple of clever LMRians have talked more about the details that I am too stupid to get into :)


selecting servo's?


I am about to build my first real robot, based on a partially gutted RAD robot.  The electronics are no problem to me, I have a good understanding of what is required there.  My problem is that I completely suck at anything mechanical.  I have been looking at servo's to move it's head, sensors, arms, etc but I cant figure out what the difference is between them, and how to select the ones best for my application.

Thanks in advance.

Picaxe :- Pwm motor controlling and servo scanning

I wish to connect 1 or more servos to a picaxe 28x1 .......with 2 motors controlled by pwm

So Far :-

I have managed to get two motors working with pwm control . (jumps on table in amazement - its my first picaxe enterprise)

I have used pins 12(pwm 1) and 13(pwm 2) for the motor control (with output 7,6,5,4 for direction ie via an Ld293 chip)

using  pwmout ....... pwmduty commands - works well.........

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

Multimeter (how much should I spend)

When it comes to small electronics (like the ones presented here) what should I be looking to spend for a digital multimeter?

Does brand matter? ...Also some of them have ranges? Im not sure I understand what that means. like a 15 range......39 range etc...?

What range should I look for minimum?



Finally finishing the "start here" bot.

I just got the part I need for the "start here" bot, which is the new GP2Y0A02YK0F. My first problem is, I can't remove the old GP2D12 from the cable that connects it to the PICAXE board. If I am also correct, The setup should be the same as the old GP2D12 right? Like where the wires are supposed to go?


Bug Toy - PID - Visual Tracking and Moon Delay

Update 2011.4.20

First hacked attempt at a P - control.. it got a little complex being multi-threaded - the feedback on one thread, the commands on another.   The result is in the video (at the bottom of this post).  I think I have to boost the kp constant a little..among other things 

Things I noticed:

Combat RC / ESC/BEC controllers and motors- Brushed and Brushless

Hey LMR I was hoping you could help me with a few questions the internet/google cannot fully teach me haha.

So I am thinking about maybe making a combat robot/battle bot (http://www.robotmarketplace.com/therobots.html) whatever you want to call it with some left over cash. So I have some questions on Brushless and Brushed motors.

What is the difference between Brushed and Brushless? So far I understand that one has three wires and the other two- +, - , brushless has a servo wire( to make it simple for me ;)    So what am I missing? Is one geared or what?

Alright - this is beautiful - All you CNC people will like this....

Near Sci-Fi like in that you could imagine hundreds of them automated... cranking out parts, possibly replicating as a new life form on the Sahara :)   Theo Jansen would approve...



Dual Cell Lipo Charging IC

Hey guys,

Can anyone suggest an IC that could be used to charge dual cell Lipo batteries (7.4V) with cell balancing? Ideally the IC would be powerful enough that it could charge even if the system is under a light load. I am looking for something similar to
the MAX 1555 IC (http://www.sparkfun.com/products/674) but for multiple cells. My google search has been fruitless - I must be using the wrong keywords. Thanks for any help!

Control Servos With PC.

Hello. I understand that this is a very broad question, and I have been looking into options but am confused as people tend to start getting quite technical with their answers rather quickly.

I am very very new to robotics, and would like to learn how to control servo motors via a PC, as in how to rotate the motor to different degrees around its axis. Ideally I am after a way that can control many servos at once.

08M2 had attitude problem; discipline applied, now behaving nominally :D

So this is for the hexaspider project I'm working on. Here's a rough timeline:

soldering alternatives - conductive glue, soldering paste ...?






Miller engine .... but it dose work

Ok it looks a mess but it dose Work .... So why am i posting this .... couple of reasons ... first off its my first proper working circuit and i have a few questions about it.

As i have  very little to work with im delighted to get this to work (hopefully that will be changing shortly .... just have to get paypal sorted with my bank and ready to order a few bits and pieces.)