automated guided vehicle

Hi I am doing a project to build an automated guided vehicle I need some help in choosing the circuit(shield). My requirements are that circuit should support following hardware

2 stepper motors(unipolar or bipolar) 4-6 sensors 1-2 DC motors (bi-directional) module to program the chip ATmega processor Can you please help me find the required shield for my robot?

You need to provide more details as to the size of your vehicle, what type of sensors you're mounting, and what the vehicle's purpose is in order to get a good answer.

In the meantime you can dig around at pololu.com and browse their selection of motor drivers and stepper motors. Their inexpensive "A4983" driver will work well with any of the stepper motors they carry.

It is actually a model for an AGV with a fork-lift before the robot to lift objects and place them at required location. The robot what I was planning is 12cmX10cm with a capacity to lift a weight of 500-1000grams. The sensors used are normal light sensors used in line-follower robot. Also the circuit should support a IR sensor to detect object. thanks for the reply

Friends ay one please help me

I don’t think you will find a shield that is perfectly spec’d to your requirements, maybe its time to get working on your own shield or module in which you add hardware capability yourself,
Get your arduino and a protoboard, some connectors and the driver chips and voila, custom shield

Hmmm, with respect, I think you are a bit on the hopeful side.

To lift 500g to 1Kg on the forks, assuming a 'normal' forklift configuration, you must aim for a Kg or so right at the back, as ballast over the rear wheels. Some of that could be as batteries but your basic 120 x 100mm size may preclude large, lead-acid clunkers.

You don't indicate which motors do which jobs so we have no idea what currents to expect. However, if you use L298 (which are effectively dual, 2Amp H-bridges) at one-per-stepper and one for two DC-motors, you are using up processor-pins at a great rate.

Each L298 will need 4-signals, so that's 12 pins used (15 if you use 'enable' to reduce current-demands.) Pin 0 is not available to us mere mortals, 1, & 2 are best kept for interrupts, leaving P3 to P10 for say, 2 steppers. Use P11, 12, 13 plus one of the pins of the Analog port for another '298 (for the 2 DC motors) and you haven't got many pins available for your 4 to 6 sensors.

You might have to consider using a shift-register to reduce the pin-count, or perhaps not all the sensors are needed at the same time? Could they be paralleled?

Consider using the Screw Shield - you can stuff several wires into each socket. I find it very handy - in fact I have one pair pre-wired for a job that I set to one side. Can't remember what the job was now, but it seemed like a good idea at the time.

Geoff

Thank you guys for your suggestions Winner can you mention what base shield would be good to start building ?