Mini Atom Bot Board?

[BANE]

Has anyone had experiance with lynxmotions mini ABB before?  I looking at purchasing it with a Basic 28 Pin chip.  Good pick??  Any microcontrollers with same function with a smaller price tag? 

thanks

Bane

[bietz]

Depends on what you want to do. The mini ABB is mainly used with the SSC-32 servo controller, or directly with servos. It's got a few 3-pin input/output ports on it, so you could attach some servos directly and sensors compatible.

But it makes it hard to make some custom circuits. You can only stick with what it offers you; otherwise, if you need, say, a pull-up resistor, you need to solder it at the back of the board, which is painful.

I think you should rather get an Arduino, which is more and more popular now (which means you can find many existing projects). It is powerful, easy to use and you can add custom circuits to it using any breadboard you want, or with a proto-shield (this one from adafruit or this one from sparkfun).
There's also different kind of arduinos, such as the boarduino, which sticks directly to a breadboard.

But if what you want is a robot with many servos (such as a humanoid), I would recommend using the SSC-32 with the ABB, because the Sequencer program from Lynxmotion automatically generates code for the Basic Atom or Basic Stamp MCUs that fit on the ABB.
If you're not gonna use the sequencer, then I think you could also send commands to the SSC-32 from an Arduino, with serial communication.

Anyway, I think the Arduino is starting to be a must-have. (It's on its way to replace the Parallax Board of Education)

Hope this helps,
Alberto

[BANE]

hey thanks for the reply bietz.  what im trying to make is a simulation of a industurial ABB in a factory cell only alot smaller .  (check out the pic listed as an attachment named final assembly...)   I figure that i will need about 12 servos, 4 IR sensors, 8 touch sensors, and maybe be able to operate using a PS2 controller .  I'm guessing i will need about 28 ports from a servo controller.  Can the arduinos or boarduino do all that?  If i use the mini ABB will i have to use the sequencer?   Or i'm i just asking too much?

check out my design for the arm!  (listed as attechment named master arm w/ linear base)

bane

[airman00]

so just get a separate servo controller for 12 servos and control the servo controller with one pin on your board, there that saves you pin space

[BANE]

but can i do that with just the mini ABB http://www.lynxmotion.com/images/jpg/abb02.jpg being only 12 servos?

[airman00]

well how much I/O pins does the mini ABB have?

I dont understand the issue here.

[BANE]

it says up to 20 servos http://www.lynxmotion.com/Category.aspx?CategoryID=66, but bietz said that i may need a sequencer.  Is this true or did i misunderstand something?  check out link^

[airman00]

Up to 20 servos can be plugged in directly

   

no sequencer needed , i think   ...

[bietz]

Definitely use a servo controller (I recommend the SSC-32, which supports up to 32 servos). You can then control it using only serial communication with one or two pins.
Since it's for robotic arms, you would have to write your own inverse kinematics stuff, so the sequencer wouldn't be of much use.

Now to control the servo controller, you can use any microcontroller board (or your custom board).
Depending on which Microcontroller you use, you will have more or less analog inputs for the IR sensors (if you use analog ones such as the Sharp GP2D12). The Arduino (based on ATmega168) has 6 analog inputs. On the ABB, it would depend on the microcontroller you use. Basic Stamps don't have any, so you couldn't connect the analog sensors directly on it, whereas the BASIC Atom/Atom Pro do have some (I think about 4).
And on the ABB, all the sensors you use must have a connection using a cable fitting on the ABB ports (for touch sensors, you can make them yourself).
The ABB supports the PS2 controller directly (although you need to add a pullup resistor if you use the Atom Pro), which comes in handy, but there's got to be ways to do that with Arduino (you could also connect it very easily to the computer and control it from a visual app. That would be harder to do on an ABB).

I've never tried to use the Arduino with the SSC-32 yet, but I'm sure it would be possible. Unless you really prefer BASIC language to C (I don't... I hate basic...), I suggest using the Arduino.

Cool design BTW!

[bietz]

Well, the sequencer is just a program that runs on your computer, and communicates directly to the SSC-32, allowing you to easily manage servo positions and speeds. Then you can export your sequence into BASIC code for BS2 or BASIC Atom MCUs, which will send the right serial data from the ABB.
Of course you don't need the sequencer. It just makes everything easier when you have to send specific sequences to the robot (say, walking sequences for humanoids). But you can simply send serial data yourself from any microcontroller. That's probably what you'll have to do with robotic arms, since you need all the inverse kinematics calculations...

There are 20 pins on the ABB, but some are analog inputs (the number depends on the mcu you use)

[BANE]

So your saying that i can pretty much just operate my robot with the ABB and not the SSC-32?  I mean it would really nice to have, but my programs wouldn't be that sophisticated and i don't mind the extra work and my wallet would be grateful .

bane

[bietz]

Well, I don't think you would be able to control all the servos plus the sensors, since the ABB only has 20 pins... (which means too few for your additional 4 IR sensors and 8 touch sensors, unless you make a circuit that would send all the sensor data to only one pin)
I was saying that you could use the board to run the program, but send servo commands serially to the SSC-32, which makes all the servo stuff much better and synchronized. It also only takes one pin on the MCU.

Anyway, if you can deal with only 20 pins, then the ABB alone should be ok, though the SSC-32 and the Arduino are boards that are often useful for other projects, so you might need them later (if you save money now, you'll still end up paying later). Keep in mind the cost of the BASIC microcontrollers for the ABB, which are pretty expensive (ABB+BASIC atom pro = 25+60$ = 85$ vs Arduino = 35$).

If you get the ABB, I recommend you get the BASIC Atom Pro 28 microcontroller, because it's more powerful than the BS2/BASIC Atom, it's got analog inputs, and a good command control servos, called 'hservo' with sends servo pulses automatically over a period of time.
Also keep in mind that if you want to use the PS2 controller, some of the pins will be occupied (but you probably wouldn't need sensors at all if you just remote control the robot with the PS2 controller)

[Admin]

what im trying to make is a simulation of a industurial ABB in a factory cell only alot smaller

interesting . . . just out of curiousity . . . why?

[BANE]

I work as a engineer in a custom bearing manufacturing plant, so i often work with people in a cell.   I thought it would be a neat project to show them a miniature model of something they work in and that i want to design someday. 

bane