[FTC]: Samantha - Connectivity at Comps

[ethan_orion]

Dear Teams,

At the Montana state championship several robots experienced connectivity issues with the Samantha module. There were some suggestions that when in defensive positions (pushing) that the added resistance increases the draw from the batteries and caused the Samantha to discount from the FCS.

Have other teams experienced this?

Any thoughts on other potential flaws in the systems, electronics/powering that could have caused the drops in samantha connections?

Thanks,

Ethan

[jcarr]

I often see robots disconnect from Samantha after a collision or pushing contest. Often it is because a connection is jarred loose temporarily (usually the Molex battery connector) or another wire.

However, the way the motor controllers work is that if you tell it to go forward, and the wheel can't turn, it increases current to the max 4 amps, regardless of what you told it to run at. You will see the battery drain quickly and the motor will burn out if you continue for more than 1.75 seconds. That can also cause disconnects and you may see the NXT freeze. You will smell the motor.

PS - a lot of the time the motor is only singed - it will still run, just at reduced power. If you are on a limited budget, like we are, we continue to use the singed motors, although we may switch them to an arm.

[pyroslev]

Below is a link to the alternate wiring method for the Samantha Module. This way your Sam shouldn't brown out and reboot at the drop of a hat.

The loose wiring aspect is also common. I tell teams to check the wiring after a match when I see a rebooting Sam and they don't check thoroughly. My advice is when you leave the field, start checking wiring connections and anywhere it can come loose, even the battery connections, to make sure your connections are solid.

http://www3.usfirst.org/sites/defaul...tha-wiring.pdf