Let's Make Robots!

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The 9.9 version of the XMOS Development Tools is now available:

Problem with my first robot


I have a problem with my first robot following firtsl's tutorial, i've done a robot like the part II of his course and i've put the same code. (http://letsmakerobots.com/node/254). It take sometimes to understand the code but finally i understood it.

You can see in the video that the comportment of the robot is not the one I expected. It seems to reverse the motor to many times and i don't why.

Can I check if my new flashy Futaba s3003 is fair dinkum?

Okay so I got a few new futaba s3003 servos cheapish, and while I'm looking around on other sites to see some prices, I notice that somone left someon else some negative feeback for the servos they bought, claiming that they were not legit futaba servos.

Not knowing a lot about futaba, I'm not entirely sure if I have real futaba servos - at this stage, they were so cheap it hardly matters, but for future reference - how does one spot a fake?

A bit of advice on choosing the right battery


I've been running around past few days trying to figure out a suitable power source for my yet to build robot. It will be powered by two 12V gearmotors (about 1amp stall), on a simple diffrential drive. I am looking for a balance between power consumption and efficiency. My rough estimate is that the robot will weigh under 1kg (2.2lbs) after construction. 

Subsumption Archecture

Hey all I found this very interesting idea in a book (The Robot Builder's Bonanza) for a way to code a robot. Instead of having a robot that merely goes straight till it hits something you have several "levels" or "layers" of code. The first one being an obstacle avoidance sorta thing, and then on the next level an aimless wander. This wander section of code which would ask the obstacle avoidance level if it was OK to move. If it was OK then the random wander would do its magic but if there was an obstacle then the obstacle avoidance would take over like a sort of reflex.

CMU cam 3

Is there anyone familiar programming a CMU cam 3? I was just wondering if we could program the camera using Visual Basic?

Picaxe.xml in gedit ?

Is it possiable to the picaxe.xml file in gedit-for gnome users, rather tha kate ?

i've got some LEDs, voltage-regulators, servos, etc.

if you would like to swap parts with me go to this (always updated)site to see what ive got:                                                     http://www.flickr.com/photos/39713005@N07/sets/72157620478638480/

[French] Science & Vie Hors-série n°247 : Le siècle des robots

(sorry for those who don't speak french)


Science&Vie a sorti ce mois-ci un hors-série spécial robot (150 pages, pas une seule pub!), et c'est vraiment très très intéressant... Les articles parlent de tout, l'historique, les applications militaires, ou en médecine, les robots au quotidien, les nano-robots, les interactions homme/machine et même la robotique amateure ququi nous est si chère...

Declare an Array in picaxe basic?

I want to make several led's blink in one direction the the other, i figured the best way to do this would be to have the output pins in an array then use a 'for next loop' to loop thru them.

But the manual dosen't say how to declare an array, so how do you declare an array?

Using Picaxe 28x1


Choosing the right connection for a network of robots

I've been reading up on robots, and in one of my books there's a chapter called Multiple Robot Interaction, which mentions having one robot as the queen, and the rest as drones. There are several ways of connecting, WLAN, Bluetooth, Infrared and I'm sure I'm forgetting lots of others. But which is the most commonly used/best way of connecting?

What to do with a drunken sailo.. err linear slide?

Ok I was cleaning up around the work bench and found this stepper and belt linear slide assembly that came from a printer. I had kept it to knock up a cheap x/y plotter, but I scrapped that idea and am building a CNC out of better stuff. It seemed like such a waste to destroy or scavenge the motor from it so I need some ideas of what to use this for. The stroke is about 350mm if something were to be attached to the belt, but theres no reason it can`t rotate continuously for something. I also have the metal strip that was used as a slide for the opposite side.

anyone got 2 spare 47k?? and you get LEDs!!

i just got my mail today with some stuff i orderd but i have forgot to buy some 47kΩ resistors and one 380Ω

i got everything i needed for my robot eccept some 47kΩ resistors and one 380Ω and i dont want to pay $15 for shipping just for two 47kΩ and one 380Ω! 

so..      does anyone have some spare 47kΩ resistors? then please PM me! (and if anyone have some spare 380Ω resistors, then please PM me too)

i am wiling to swap with ~5 red or blue(you chose) clear(super powerfull) LEDs i have, for two 47kΩ and one 380Ω!

Complet newbie needs help with Picaxe 28x1.

I m such a newbie, please forgive me.

I have the picaxe 28x1 starter pack and i'm trying to do the "Test the System" tutorial, but im am so lost.

When it says 'connect to pin 4' i notice there are two pins side by side on #4, which pin do i actually connect to ?

do i have to connect both? Been using the pin closest to the Darlington chip, with out success.

Also there are two 'v' pins on oposite sides of the board, which one should i use? or does it matter .

Robot event calendar

There is a lot of robot related events around the world so why not make a Robot event calendar?
This way LMR users know were to go and show there robots and met other LMR users.
Here is a few links to start whit.

Odense robot festival 10/12 Sep. 2009 http://www.robodays.dk

DTU robocup 14/16 Apil 2009 http://www.dtu.dk/subsites/robocup.aspx

Lowest RPM of an electric bike motor?

What is the lowest possible RPM of an electric bike motor?  It seems to be the cheapest alternative to a slow gearmotor.  Thanks.

Would this motor be able to lift 150 lbs?

Would this motor lift me?  150 lbs or so?




Its for my walking chair, it will be chained to a shaft and the shaft will have about 150 lbs (NOT static load) or so of force to deal with.


Thanks :)

Switching voltage regulator but what after it ?


Here is a hopefully simple question, and a little explanation to go with it.

Okay,here we go...

I am currently adding extra sensors and bits and bobs that eat up power on my robot and I would like to give my robot a bit more power to work with and so that it can run longer. That is simple thanks to12 AA batteries

My robot uses a Picaxe 28X1 and from what I have read it doesn't like more that 12V.

Here is the problem: my 12 AA's give out  18V ( and yes I did use a calculator! ) but I can only give my chip 12 of those 18V.

female to female jumper cable search

Im in a bit of a situation at the moment. i need some female to female jumper cables but cant seem to find anywhere in the jolly old uk that sells them.
Any help would be much appreciated.
Tom J

Edit: thanks to all for your help.
ive found a site that sells them but i think ill follow mike and make them as the price is high.

Best for Beginners?

I am an absolute beginner... i have very little experience in electronics, very little experience in mechanics... but i am an expert programmer...  my question is: what do you recommend for a beginner wanting to get into robotics?  I am thinking I might want to get a roboduino board but I see here a lot of people are using picaxe. 

The advantages of something like the roboduino is that the board is pretty self contained and wouldn't need a seperate board to drive the servos...

Any suggestions as to what type of micro-controller might be best to start with?