Let's Make Robots!

Cannot get the motors to work for this robot

hey guys. I am not getting any movement or anything from the two dc motors. I am using a l239d driver 

here is the code and also a attachment of the wiring.Thanks I hope someone can help me

#include <Servo.h>

#include <NewPing.h>


//Below are the symbolic constants. Instead of having to type in a non-sensical pin number each time we want to do something we can write an easy to understand name which represents the pin, the compiler will then replace the names with the numbers

#define LeftMotorForward 8

battery case question

hey guys i salvaged this outta a toy wondering if i connected it wrong.

can you take alook at the pics and offer some insight. thanks

simple robots collaborate to lift a human body above the ground

Hey guys, 

 I am trying with friends to design a relatively small and simple robots that can collaborate together to lift a human body or move a human from one place to another. The assumption is that the human is laying on the ground and will not be moving. Assume a very simple enviornment.. I have a basic idea in mind, but I would like to hear more ideas and suggestions..


I've been setting up my profile for selling on the marketplace and am wondering if there are any seller settings or tables to use for adding shipping classes. 

For now I've included shipping costs into the price. 




FrankNeon on LMR.

Tha $0.99 shipped list

This is a list of cheap, $0.99 shipped parts when you find something share it! If its just a screaming good deal under $5.00 please post as well, the idea is build your inventory $5.00 a week or a pop at least.

Mogul: lcd driver


jinx 4 aa battery holder


oss BC547 transistors


jinx 100K resistors, shipping is $2.00 varies for basket


Trex Robot Controller Battery voltage on Voutput does n't match the input

Recently I got a Trex Controller and was trying to understand the board not yet started with the motors. I connected a 11.1 V 6400 LiPo. At first I was able to see around 11.6 V on the input and the blue Voutput. I was trying out the sample codes and checking the voltage on motor outputs but never saw anything. It always show zero. Now I am seeing the D13 LEDs turned on along with the fault motor LEDs. I connected the battery properly but I no longer see the same voltage in the blue Voutput for the battery. I think it is reading voltage from the USB cable connected to PC.

Can ED-209 be made to do PID balancing, like a MIP robot?

Hi All,

I'm having some trouble mentally figuring out how ED-209 could be combined with a two-wheeled PID balancing robot.  In a two-wheeled balancing bot, the gyroscope is ideally placed close to the axis of the two motors.  If ED-209 were to have "PID feet", would the gyroscopes go in his feet?  or would one gyroscope go in his torso to keep it balanced while his feet walked here and there?

First Arduino Obstacle Avoiding Robot

I am working on putting together my first Arduino robot. This is the set up I have come up with based on the parts I have on hand. Do note that the IR sensor is really a Parallax Ping sensor, but I couldn't find one of those in Fritzing. Does anyone see anything that stands out as a problem? I know that I should really be using a motor driver, but I don't have one yet, so I am hoping that this jury rigging will get me by till I can order one. Comments and suggestions are welcome!!

Speech Recognition

Hello everyone, I am a beginner and new to letsmakerobots.com. I love the site. I have a project in school that involves designing a speech recognition system,and am in dire need of help. Suggestions and resources would be a life-saver. feel free to drop a message,or better still,email me at: anijapan5@gmail.com. Thank you all.