Let's Make Robots!

Sparkfun's Ardumoto

Hi

On the Ardumoto, if you have it connected up to the arduino but no motor's connected are the direction lights supposed to illuminate on when receiving signals ?

I have the code uploaded to Arduino and i have processing running and it all works (as far as i can tell)

Servo selection problem

I have been working on a robotic arm for my first solo project from scratch. Everything has gone well for the most part, I will post the robotic arm when it is finished. I have run into a problem though and need some help with what to look for in a servo as far as specs. The problem is, the first vertical joint cannot handle the weight of the rest of the arm very well when it is idle. In motion, the arm swings fine, when at rest, it has a tendency to just fall over. I am assuming I need to buy different servos for use in my arm.

Micro servo for robotics?

Have any of you tested this micro servo? It looks like it was designed for robotics, has mounting holes on the sides that usually are called top and bottom and has an opposite hole to the spline. So it should be easy to mount it on brackets and build a biped or an arm... Any thoughts?

http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewitem.asp?idproduct=7026

Mr. General sensor issue.

After getting the kit together, Mr.General just wont do as supposed! When looking throu a camera only two of the infrared sensors led up? I have had a electrician look at my soldering and he could not find anything wrong.

When turning it on all green led's shine brigthly, but after a few seconds it starts buzzing from the speaker and the green led's starts blinking with the buzzing. If i then touch the wiring on the breadboard the head starts to tweak, and sometimes the green led's get solid again. Have also tried to change all the wires. Still the same!??

Please help!

Dagu Gear Motor Pain

I have been flumoxed by a motor issue recently, and was wondering if others had some strategy dealing with it successfully.

simple sound detection - headphone level input

So I have found a few different sound detection circuits, but they usually integrate a mic and an amplifier circuit. I want to make a circuit that takes in headphone or line level audio via 3.5mm jack that will close a relay when a sound is coming through the input. From what I understand headphone and line level audio has more power than mic level audio signals. The audio signal does not have to continue on to a speaker or anything after going through the circuit, and doesn't have to sound like anything in particular (can just be a series of tones and quiet periods) 

inexpensive motherboard for linux

Hi there!

Is there anybody who knows an inexpensive motherboard yet powerful enough to be able to run Linux OS? I have already dicovered RoBoard and Mini-ITX motherboards, but I am looking for something else if there is any!

Ideas for "portable" or "backpack-ready" robot

I find myself more and more out in the non-robot-speaking world telling people that I "build robots". From there, there is a long pause and then me, stuttering through a terrible explanation of what these "robots" actually are. I have tried words like "electronics hobbyist" and "educational robots" and "classroom settings" --I have even tried "hardware developer specializing in the domestic,hobbyist and educational fields". Its usually a tough crowd though.

What components for a navigation solution?

Hi All

It must be that my previous question http://letsmakerobots.com/node/28808 was wrongly phrased as I am sure there are plenty of knowledgable people here. Anyway, I will try re-phrase my question.

Could anyone be so kind as to tell me what components would make for a complete navigation module. ie. a module that knows where it is.

I am asking in terms of a small household or garden robot so GPS is probably not relevant.

current flow

Hi guys, I have attached a schematic that I am have some trouble analyzing, using Kirchhoff’s current law, how will the current flow through R4 and why is it in that direction?

servo controler

i have built a servo controler using ic555 and a reostat of 100k and all it does is turn clock wise and jams in the end (the circuit is taken from-http://howtutorial.com/howto/how-do-you-build-a-simple-circuit-to-control-a-servo/) please help me to control the servo.

Can a 3,4V solar panel charge a 3,6V NiMH battery pack?

Can a 3,4V (open circuit voltage) solar panel charge a 3,6V NiMH battery pack?

RAD 2.0 Schematic?

Does anyone have a schematic or diagram outlining the electrical components for a RAD 2.0? 

Rocket Brand Studios New Products 2.7.12

The new products are in! The new products are in!

More L293 Problems-Any Ideas?

Here's the idea-to use the L293 as a one direction speed control with PWM on the enable.  Theoretically I could do something like this:

With a pull-up and a pull-down to the logic pins respectively to keep one high and one low.  The problem is when I tried it, this happened:

The motor never moved and the chip and the board are one now, I'm afraid.  Luckilly I bought about 8 of these.