Let's Make Robots!

"Shell" Materials

i made a robot and i want to make a shell for it to cover all the wires and junk. i tried soldering aluminum together from an aluminum sheet but the solder wasnt sticking so i figured that didnt work. Does anyone know a good place to get like plastics i could use or any other good material you have used before?

Trying to encapsulate a servo instance, no movement

Hi there,

I'm having an issue with encapsulating servo functionality in its own class. What I want to do is creating a class that contains a couple of methods that control a servo more or less autonomously, in such a way that just requires me to set the context and then in the loop calling myservo.update() to have the myservo class take care off its own. Very OOP indeed :-)

For some reason I just can't get it to work. Brought down to the bare minimum, I have three source files, main.ino (off course), myservo.h and myservo.cpp:

myservo.h contains this:

Controlling motor speed

Is it possible to control the motor speed through programming with a picaxe board? or do i have to buy the motor with the speed i want?

Beware: Your 3D printer might be trying to kill you


Well, here is some scientific support (see attached pdf) to why your 3D printer might try to at very least harm you!

The study only incides over particle emission, and not the chemical nature of the emitted particles and yet it can be scary enough. That, added with my reported symptons after going on a 3D (ABS) printing binge: persistant chest pains/disconfort should be enough to keep you on your toes.


So you better ventilate/filtrate if you're into this messy business.

How many 9g servos can an USB handle.

I need some confirmation to be sure - USB 2.0 can supply 500mA, and typical small 9g servos draw like 150mA, right? That means it's safe to have an arduino powering 3x 9g servos, running off an USB port..?
Also, how important is it to have an electrolytic capacitor in the start of power supply chain, to store current? At least in this particular case - how much will it help protect the USB port? Or if all motors are stalled, capacitor will run out of stored power, and the USB port can still be damaged?

BEAM Robotics

I am building a three wheeled, light sensing BEAM robot as part of an engineering project, but my knowledge on electronics is very poor. I was wondering if someone could help me with the circuit. My robot is going to be light sensing with a touch sensor around its perimeter so that it can avoid obstacles.

How to calculate how much weight my servo can handle?

I have a Tower Pro 9g Micro Servo (SG90) and it's datasheet says it's stall torque is (Stall Torque at 4.8 volts = 16.7 oz/in (1.2 kg/cm)), but as I haven't learned physics, I don't know how to calculate how much weight it can handle stacked on top of the arm/horn.

Homemade Artificial Muscles from Nylon Fishing Line

There was an exciting discovery that hit the news last month -- researchers at the University of Texas learned that appropriately coiled nylon monofilament line could be used to make heat-activated artificial muscles. Here's an article on it: http://io9.com/scientists-just-created-some-of-the-most-powerful-muscl-1526957560  I've had some success duplicating their work as a hobbyist -- in particular, I've gotten one of these muscles to lift a suspended ferrite core about a centimeter, then relax again.

LMR product

bdk6, 6677 and I were in the shoutbox and were talking about a product or something to help fund lmr, we all had privetly been thinking that with all the smart people here at lmr we could create a product or two that we could sell here in the shop or even licsense to some one like sparkfun, seed, adafruit or other.

ganging servos together

I am in the design phase of building a robot arm roughly 40 cm long that can pick up several pounds ( 1 kg for easy math).  To get a 40 kg-cm torque servo is a pretty expensive servo ($60 at pololu.com although anywhere else anyone knows something cheaper, please share!). 

Has anyone ever tried to gang several servos of the same brand and type together to work in concert?  I was going to put a balancing weight on the far end which will help, but still calls for a pretty expensive servo (30 kg-cm)

Can't upload any pictures

Hi there,

I can't upload any pictures for some reason. This is what I see when  I open the upload window:

Directory error! - files/userpics/u21387

Anybody an idea?

I'm trying to put up a write-up about my BoBtheBiped...



Test email service

testing the emain notifications

Do we want a LMR WhatsApp or WeChat group?

A while back I asked Frits what he would think about a WhatsApp or a WeChat group for LMR. 

Recent events about WhatsApp may change a lot but I guess that's a reasonable question if we want a 24/7 chat for LMR or not. The SB is ok for the use on a computer and the SB app is doing it's job as well but it's still not an optimal solution.

What I would like to read below is your opinion about that idea. Do we need a group and if yes, how we are going to do that?

Damage Assessment on the Kossel

Well, I ran into my first real fail of cheap parts.  Apparently the RAMPS 1.4 board I bought has two defective mosfets.  I'd like to take the blame and say I blew them, but I was being insanely careful.

And after inspecting the mosfets I've found physical damage to them.  Sigh.

Robot ATV?

Does anyone else want to make a robot out of an ATV?  How hard can it be?  GPS, Laser Range Finder, sonar, compass, etc- they're all off-the-shelf-parts nowadays.

Color Tracking with Arduino Uno and CMUcam2


I am working on a school project and am struggling to figure out how to connect these two systems and code them.  I was wondering if anyone could offer any program examples or advice from similar experiences.  Thank you!

LEO the Arduino Compatible robot

Hi Lets Make Robots,

We have a robot kit on Kickstarter that we think people might like. It is the first kit we designed that makes use of our HUB-ee wheel hub motors (which you can already get from places like Sparkfun and Robotshop.com)

New tutorial on how to make an Arduino robot

I posted this on the Facebook page, but thought I'd post it here as well.

I just finished writing an in-depth tutorial on how to make an Arduino-based robot. It's targeted towards beginners and should help someone completely new to robotics to build their first robot, but anyone making a robot with an Arduino will find it useful. Here's picture of the robot I make in the tutorial: