What about connecting also 5 Volts from the usb cables together? No?
If hard disk can be stopped but display lit and usb communication going that would be nice. The laptop is in the shopping basket with lots of soft material around, but one cannot be too careful with it.
Hi, Do you need the 4 USB's for Communications? Or some of them just for power?Either way, you can probably butcher (AKA Modify) some USB cables to supply the +5V from a different source.
The laptop is mainly a datalogger.
An alternative approach is to ditch the laptop, and get SD shields (or EEPROM) for each arduino, and let each one do the logging, and then combine them later on the laptop. You probably need a RTC (real time clock) on each arduino to get the timestamps right.
You didn't say what form the logger was capturing the data, but you might be considering just writing it to an HD.That's quite a risky thing to do on a laptop that is being subjected to vibration. If you write to an SD card or USB flash drive, you can leave the HD safely powered off.