Ground mistake

Hi all,

I am currently working on a robot. All the grounds coming from all components are grouped up. I have an ssc-32u, a few sensors, a sound device, etc...

The common gnd wire should have gone to the gnd pin on the arduino...i connected it to the 3.3v pin instead..all components remained on but did not work correctly. everything seems to be working now that i connected it back to the gnd pin. But still a bit paranoid. What do you think about this?

Thanks!

If 3.3V is your only power source and all grounds were connected to 3.3V, then no harm done. All electronic components would see 0V difference for all pins.

5v is my main source for these comonents. I mixed the common ground pin with the 3.3v instead.

Still nothing to worry about as the max potential difference seen would be 1.7V, far below the specification limits.

Thanks! Another question. if i connect the ssc-32u servo controller (powered by a 7.2v) ground in common with the arduino and sensors ground will it be ok? Is there any limitations when it comes to common grounds coming from separate higher voltages connected to the arduino gnd pin?

No limitations for qty of ground connections. Its good to use separate ground wires and have them all terminate at a common point (usually GND terminal power supply). Also, they could all terminate to a ground bus. Using separate wires in this manner avoids ground loops. Connecting from one GND connection to another (in series) creates a ground loop and can create problems.

Is there any limitations when it comes to common grounds coming from separate higher voltages connected to the arduino gnd pin?

No grounds must be connected together.

http://www.thebox.myzen.co.uk/Tutorial/Power_Supplies.html