Let's Make Robots!

Tips for making walking robot

Please send some of the designs or some websites  for making walking robot.

Using Xbee for wireless program uploads and debugging with picaxe


I have recently tried to use my Xbee modules to perform wireless downloads and debugging for Mr. Tidy but have had no luck.

The Xbee is a 3.3V device so I have translated the voltages ok. The Xbee manual states that by default the modules work transparently. BUT it also states that the idle state should be high, picaxe wants a low idle state so perhaps I just need to invert the signals. The next problem then is do I invert on the PC side as well??

ByVac BV513

A new type of Micro controller has just been released from ByVac.


it seems to be a very nice beast. ( I just won one ), I'm nothing to do with the company, I've just used their 12c lcd controllers before 

can i still add a laser, speaker, led?

in my robot SC-QR-1 i have allready used all 8 servo-ports.

but can i still ad a laser(to see where it looks), a speaker(for it to call hor help or showing some sound-emotions..   etc.) and some leds(like a red to show power, white/bright to help my "primary-back-mounted-not-night-vision-spy-camera") 

and if yes would the servos disturb the lasers, speaker and leds?

and i was also thinking, stuff like the sharp ir sensors have ir leds in them, could i attach an led or laser to those pins??


please reply!! :D

PWM with l293/l298

I hit a wall when I was trying to use PWM on the enable pins of both l293 and l298. Whatever  PWM frequency I choose it seems that I loose a lot of torque on the l293/l298 outputs with the PWM at maximum (255).

Browsing around searching for implementations I have seen that most of the time PWM is used on the enable pins, but on some (very few) designs I have also seen PWM on the input pins. 

The question is:  which is best/recommended?  PWM on the enable pins or on the input pins?

Where to start, cheap!

Hi evrybody!

I really wont to start at building robots, but my mom thinks that i will drop the subject after 2 weeks or something. Then i have bunch of questions but only one main question at the moment:

Can you juse Java to program Robots.

I wont to build a car, and i wont it to turn out really cheap! EXSTREMLEY cheap! I heard of Android or something like that, i hope you can help me :)


Ps: My mom DONT wont me to weld :)

Arduino and sensor from yerobot.com

YeRobot.com is a newly founded company which is the main distributor of DFRobot.com in EU. 

 It carries Arduino series product and URM sensor series. 



Yellow Drum Machine Code

The creater of the YDM posted his code on the page where he originally documented the build, and I was going to use it as a starting point for my soon-to-come build. 

I can't seem to find the link for it. Anybody know where I can find it?



Modifying Parallax Ping)))

I'm wanting to make a small physical modification to a Parallax Ping))), however I'm not sure that it won't destory the component.

 What I'm wanting to do is create a backlight for the ping (such that it would look like glowing eyes). The way I imagine donig this is by drilling a small (maybe an 8th of an inch in diameter) hole in the side of each cylinder on the ping, and insert the the tip of a standard (or possibly smaller) sized LED into the hole from the outside. This should glow the inside of the cylinders fairly well, and should have a cool affect.

DC motor control - BS2

Alright. This is the last element for my robot to final come together. I need some help with DC motor control for my robot which will interface with the basic stamp 2. 

Here are some requirements:

- Able to go in 2 directions (DUH!)

- speed variations

- simple and easy to make

- easilt programmable with basic stamp 2.


thanks in advance  

Transistor Confusion (again)

Greetings fellow meatbags.

Calculon is trying to hook up a pimpin motor to his Mr Basic, and has come across something very confusing with his transistor.

Here's what he's trying to do with a nte123 pulling a seperate power supply to a motor made for 3v:


He also tried it with a 2n3904. It didna work for either. According to his understanding of NPN transistors, the output from the picaxe should switch on the tran, and pull the 3v through the motor. No?

Idea: Instant messaging for LMR members?

Hi all,

Was just thinking while shouting in the Robot Shout Box, why not have an instant messaging server for the LMR members?

I have some experience with the Ejabber instant messaging server, I think it could be integrated with some work with the drupal user database.

So what do you think? 

(oh yeah and it is spelled idea ... doh)

Bearing mounts

Hey there LMR,

 I've hit a bump in a project of mine. I need a simple assembly to house a small ball bearing that will support part of a robotic arm assembly. It plays a part in the wrist joint, as one side is directly servo driven but the other needs a bearing to hold in steady. The bearings I have are 8mm in diameter and have a 4mm diameter hole for a shaft or bolt. I have access to aluminium sheet, acryllic, and MDF wood, as well as M2, M3, M4 bolts and rivets for fasteners. Anything else I will have to source, but it shouldn't be too hard of a problem.  

Future Robotics Engineers

Check it out everyone. We had our first Arduino class. I was excited to see how many parent & child participants showed up. We were expecting 12 total but had double that!

Here are some photos.



New Axepad for Linux Ubuntu users

The creators of Linux Axepad have created a .deb package for Ubuntu users. I was having issues with the other version off of rev-eds site. So far no issues with this one. 


Once you have it installed you have to open a terminal and run "sudo linaxepad"

picaxe programming; only one interrupt condition?? what??

Hi more knowlegable people.

I've made a little robot that runs into walls. It's meant to do that, but it's not meant to try to burrow through the wall - so I have what I'm sure is the normal bits and pieces - just debounced trigger switches and a ~10ms main loop that can react fast enough to change direction and stop the burrowing...

Beginner robot..suggestions please!! (Axon and VEX for the bot)


Im envisaging on building my first robot, so would greatly appreciate any advice.

About me > I've some basic programming skills through GW-Basic and QuickBASIC which i learnt nearly 10yrs back. I suck at C programming, and am not well versed with microcontrollers/electronics, although im sure i can learn (maybe not C!!). Mechanically, im sure i can conjure up something fairly decent, if not pathetic!

Building strapping

Im not sure what it's called, CTC can you enlighten me? But it's cheap and easy to work with. I've used it on Retro bot for the extra battery holder http://letsmakerobots.com/node/8004 You should be able to get it from you local building supplies store. Easy to bend, and cut it with tin snips.