Parallax Pings and Servos

Hi, all. I'm trying to build a robot using the Parallax BoeBot with 3 Ping sensors and the Arduino board (BASIC stamp is not suitable). What I'm trying to do is have the 3 Ping sensors sense for objects to the front and sides and have the bot move to a predetermined location while avoiding obstacles. So I got all the hardware set up, and the software written and was testing with the bot powered by the battery pack (4xAA) and found out that the Ping sensors weren't working. I changed batteries and the Ping sensors seemed to work, but they still fail to work periodically... I hooked it up to my laptop and ran the bot using the USB power and it all worked fine (the Ping sensors I mean, not the algo, I haven't tested it on the actual obstacle course)... problem is, I cannot possibly be following the bot around while it's searching for a path to the destination...

My question is it really a problem with having 3 Ping sensors and 2 servos running on the battery pack? Or can it be the way I mounted the Ping sensors? Or the way the software is written (e.g. Checking the Ping sensors in quick succession)?

I have tested the Ping sensors individually and all 3 at the same time, separately from the motion algo (i.e. not running the servos) and they seemed to work fine. But these tests were done connected to the laptop. I don't know how I can test the Ping sensors to see if they are returning the correct values without connection to a laptop, and just running on the battery pack...

Any help or suggestions is appreciated. I need to complete this in 2 weeks time and I intend to add 2 IR pairs and 2 photoresistors as well, I just hope the battery pack can support all these...

Thanks in advance.

My question is it really a problem with having 3 Ping sensors and 2 servos running on the battery pack?

You need to add up the current requirements for the 2 servos and 3 sensors. Is that current requirement capable of being met by 4 AA batteries?

It's certainly easy enough to test. Simply wire 2 4AA battery holders in parallel, to double the current capacity. If the problem persists, batteries aren't the problem. If the problem goes away...