Hello Everyone, I have been into robotics for about ten years now. I usually build my own stuff. I really want to buy a BRAT robot but I’m not sure which one to buy.
Autonomous
Or
Serial Port
I understand that you control the serial port version with a computer or controller and that the autonomous can be pre-programmed to interact with its surroundings.
Are the controller boards different for each model? Couldn’t you program a Serial Port Brat to be autonomous?
You build the BRAT pretty much the same, regardless of whether you are going to have it be autonomous or serial port. The main difference is for serial port you don’t necessarily need the microcontroller and can tether it via serial cable or use a wireless link between it and the computer. It depends on what you want to do. For serial port control, you can still use the microcontroller to process and interpret commands from the main computer and then do control functions on the robot.
The other big difference between serial port and autonomous control will be in the way things are programmed and how sensors are used to give input to the microcontroller. Of course, much of this can also be accomplished by sending sensor data back to a computer via a serial link, processing that data, and sending motion commands back to the robot.
You must have the microcontroller “brain” for autonomous control, of course, but it is optional for serial port or wireless serial direct control. The nice thing is you can start out with just serial port direct control for testing and then add the onboard microcontroller at any time for more advanced and/or autonomous control later, so you can ease into more advanced stuff when you are ready or want to do other stuff. In any case, the microcontroller you might need is the same and does not need to change as you move on to more advanced stuff.
This would be true for any robot you might want to build, not just the BRAT. Start out with serial port direct control and add on a microcontroller “brain” whenever you might be ready. The BRAT and all other Lynxmotion robots are extremely upgradable and changeable for whatever you might want to do. For the BRAT, just take a look at what SN96 has done with his Bratinator and you will see just some of the possibilities. There is a LOT of support here for the BRAT and various expansions to it for many different configurations, as well as all other Lynxmotion robots.
Basically, your imagination will be the only real limitation to what you can do with any mode of controlling a robot. I’d recommend going with serial port control and moving on and adding a microcontroller for more advanced and/or autonomous control later. You can always add on to any Lynxmotion robot!
So if I buy an autonomous bot, then buy a SSC32 controller I will be able to do either correct? Do I need an H-bridge in conjunction with the SSC32 to control servos?
As LinuxGuy mentioned you can do almost anything whichever way you go. As for your last question no you do not heed an H-Bridge in either setup.
If you buy the Autonomous bot you may or may not want to purchase the SSC-32 as well. You don’t need it, unless you decide that you would also like to use a program like SEQ to build up sequences for the brat, which controls the different servos using the SSC-32. Otherwise you can do everything with just the Atom Pro. You can do semi-equivelent stuff to seq by using your own custom program and serial interface to the PC. There have been a few of us who have done this, including myself.
Also you might want to consider buying a few extra components/sensors, such that you can control it using a PS2 controller or with a TV remote control. There are sticky threads in this forum about the TV control and some other threads about using the PS2…
Although what Linux guy has posted is true, if you are specifically discussing the BRAT tutorials we offer, and what you can do with them without much learning on your part…
BRAT for SEQ is controlled from a tether (db9 or USB to serial cable) or bluetooth wireless serial com connection to the PC. The movements are created and played back from the PC. You can export these sequences as a basic atom or basic stamp program. It would require you to add a Bot Board II and processor to the bot.
BRAT for autonomous operation does not require or include the SSC-32. All movements are done using the hservo command, it’s like a fewer channel built in SSC-32. This allows the bot to play sequences while it’s processor reads sensors etc. We have tutorials that make the robot walk, avoid obstacles, get up if laying down on front, back and sides, detect and kick water bottles.
We are currently working on adding a tutorial for PS2 control as well.
There are two boards: the SSC-32 and the BB2. The SSC-32 is a servo controller. It’s only function is to execute commands sent via TTL or RS232. A computer capable of running software needs to issue these commands to the SSC-32 using one of the serial protocols mentioned. The SSC-32 cannot work as a standalone board, it only works when it is connected to some type of computer that sends commands examples are: Laptop PC, BB2, PDA, etc…
The BB2 (Bot Board 2) is a microcontroller (Mini computer) that can be programmed using the Mbasic language. This board can work as standalone or in tandem with the SSC-32. For autonomous control, its common to have both the SSC-32 and the BB2 working together.
Start out with serial port direct control and add on a microcontroller “brain” whenever you might be ready. 
I’d recommend going with serial port control and moving on and adding a microcontroller for more advanced and/or autonomous control later. You can always add on to any Lynxmotion robot!