Let's Make Robots!

I2C vs Serial

I hereby submit another plea to the robot gods out there:

I've read a lot of very informative info on both i2c and serial communication as a way for one IC to control others. My question is: which will work better for my needs?

My plan is to make a robot that has a seperate IC for each aspect of its behavior (movement, communication, etc.). So which is faster? cheaper? fewer wires? easier to program? I'm sure both have pros and cons.

Okay, go.

? Sending Serial Via IR?

So I read Frits's post about his little "data-in, data-out" RF doo-dads and it got me to thinkin'...

Wanting to hook up batteries to 3 servos

I want to hook up 3 servos to some batteries.  Since it show it operate at 4.8v and 6v, that mean I need 6v to get the most out of one.  Does that also mean I just need 6v for altogether to make them all move.  They will all be moving at the same time.  I figure I would need more V then that but maybe it would have to do with mah.  Could someone explain how it able to all three use the same power source.  Also does having more mah mean the battery last longer or make it stronger??? thanks in advance.

H-Bridge NPN vs. PNP

I usually make a H-bridge with 2 NPN and 2 PNP transistors but I recently noticed that there´s allot of schematics on the net showing it with 4 NPN transistors and I started wondering what´s the right/best way to do it??

 

H-bro.jpg

Do robots have personality?

Many sci-fi shows and books depict robots with personality, sometime as the result of an accident like the movie "Short Circuit", sometimes intentionally as in the movie "I, Robot". Now that I am working for Dagu I have discovered that even simple robots demonstrate personality.

Modifying source code (IR instead of ping)

So I have finally found a code that seems like it is going to work from this node:

http://letsmakerobots.com/node/2744 

 

However, I want to use a sharp IR sensor instead of the ping, as the sharp is cheaper and im on a strict budget for this project. I have no idea how to change the code, as I am just beginning to learn the language. Can anyone help me out? Here is the source code from that node:

 

Arduino EMF detector

Arduino EMF detector !!!

Interesting Sensor project from makezine

Adjusting for air/water current

First a terminology question:

What do you call the direction a boat/plane is pointed?

Yeah it is a silly nit, but I am documenting a design and people will pick nits. A simple example is a boat crossing a river. For simplicity, consider the river flowing from N to S and boat crossing from W to E. So the bearing/heading is E. But if point the boat due E you will go SE, so you have to point the boat NE. When I learned to kayak, this was called ferrying and the angle was referred to as "set", but I hate using such an overloaded term.

Best Arduino (compatible) board?

I want to make the next generation of the "Start Here"-instructions be based on Arduino instead of Picaxe.

Some will say that it was about freakin time, but so far the advantage of the Picaxe has been that I could chose a single board that "did it all": Hook up Motors, Servos, sensors and everything.

This, and the fact that the Picaxe Basic Language needs very little introduction, made it the choise - even though the Arduino series has been a lot more popular recent years.

Manual compile and upload

We decided to get rid of the Arduino IDE for our project, and switch to make/avr-gcc/avrdude. Sure, the IDE is great for beginners and those who write small to medium-small projects, but it's awkward to use with larger projects using lots of files and several people coding at the same time. And the PC our university has provided to us is quite slow so some stuff take way too much time.

The transition wasn't as easy as we had hoped for though, and it took a day to figure everything out. So to hopefully make things smoother for others, here's how we did it.

Two +V and 0V

On the Picaxe-40x2, there are two pins for +V and 0V. Am I supposed to conect both of them? What are they for?

Self-Replicating Stationary Phototrophs

How many of you guys garden?

Servo motor

How to control a servo motor (2) by just twisting or turning the other servo motor (1) or potentiometer using hand?

The servo motor 2 will follow the movements of the servo motor 1 or the potentiometer.

Not necessary to use a servo motor for the servo motor 1, just any solution that would perform what is shown in this video (http://www.youtube.com/watch?v=zZwnyZPkylk&feature=related).

Thanks.

Good at designing robotics parts?

I saw this on Hackaday today, and immediately thought of you guys:

Which micro-controller etc should I buy?

As some of you may be aware, I'm still very new to this pastime, both with regards to electronics and programming, but have built a couple of bots which have been reasonably successful, using an Axon II Microcontroller, shown here http://www.societyofrobots.com/axon2/.

I am finding it extremely difficult to get on with the C language (I'd never even heard of it until about 3 months ago), but I do seem to be able to "read" basic fairly easily.