Let's Make Robots!

Stepstick A4988 issue

Recently I came across the following odd observation with a Allergo A4988 based stepstick stepper motor driver. I hope others will redo my experiment and tell if they see the same.

Those who doesn't know the stepstick can have a look here: https://www.pololu.com/product/1182 Of course mine are cheap clones I got from ebay, but they should work the same.

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

first robot

hi guys i posted about the james robot which i am not having any luck with. I am wondering if you could suggest a robot i could build that has easy instructions so i can at least build somethibg and heal my ego. i only have one micro servo a ping sensor and two dc motors. and arduino uno


Earthquake in Nepal - Quick Update

Hello LMRians, 

Long time no see. For those of you who might not have been informed, Nepal was struck by a massive eathquakeThank you all for the wishes during these dire times. I am safe with my family. So are my friends.

James robot driving me crazy

hey guys i am seriously losing my mind. I am very eager to leanr and improve. I seen this project and i really wanted to build it. Its been like two months and i still am.having issues.


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.

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.

Kickstarter 3D Printers

Hello bot brothers and sisters,

I strangly ran into some extra money not needed by our daily expenses.  I'm thinking of investing it in a second printer; a printer from Kickstarter.  I was curious of what some of our citizens thought of these two:

Interfacing arduino with SIM900A GSM module

Hello guys, I'm new to GSM modules. I've a very little idea of there working. I bought my gsm module from here: http://www.ebay.in/itm/GSM-GPRS-SIM-900A-modem-with-Stub-Antenna-for-PIC-Atmel-Arduino-Raspberry-Pi-/291389483047?_trksid=p2054897.l5673

I'm trying to send sms from the module but it is not working. I found the following  code online but it is not working


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!!

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?


The new droid from Star Wars. Whoever makes one first wins at LMR this year.

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. 

Changing Polarities on DFRobot 2A Motorshield

How to change to polarties of the motor shield to change the direction of the shaft? DFRobot's 2A motor shield has only 1 IN ang 1 EN for each motor.

From what I've learned, to be able to switch directions, you need to change the polarities. Is there something I am missing?

Arduino Uno R3 Refusing Upload

After a very long absence, I have finally returned. I'll bet none of you even remember me!

Anyway, I got  a new Arduino Uno R3 yesterday in the mail. I installed Arduino Software 1.6.3 (latest stable release) and tried to upload the Example sketch, Blink.

It compiles fine and finds the board fine. But when it comes to uploading, it always get's stuck. It never gives me a message telling me the upload is completed. The progress bar always stops at about 80%. I have been letting it sit like that for about an hour now.

Any ideas?

Seckill Activity: ICStation Atmega328P UNO R3 Dev. Board $7.00

ICStation New Seckill Activity is ON now.

Can't upload a script to my Arduino mini

I just received my first Arduino. I hooked up a pro mini Atmega 328 to a breadboard along with a mini Usb adapter.

I read all the directions on the Arduino site on how to hook both of these up and followed the recipe HERE.

This is what it looks like.

First arduino setup

Laser wood cutting

I'm working on outfitting a shop in an RV. I've been told that the noise from things like a table saw might be enough to get me kicked out of an RV camp so I'm looking at alternative ways to cut wood. Right now I'm looking at cutting up to 3/4 inch plywood and 1" of hardwood.

Would an affordable laser cutter (say under $10,000) be able to cut these types of wood?

I need to be able to cut up to a sheet of 8' by 4' plywood or maybe up to 8' of normal wood.

Is this a doable thing? Is it quiet?