The power pins are as follows:

About Uno Flash To start a game, turn the game on and choose a setting – infinite, 4 second, or 6 second time limit. Each player is dealt 7 cards and they activate the red button that is closest to them. The first difference you between Uno Flash rules and standard Uno rules is the game unit automatically selects a player to start randomly. How to Play UNO. If you're looking for a fun card game to play with friends, give Uno a try! Each player begins with a hand of 7 Uno cards. To play, match one of your cards with the card that's been dealt with.

Vin. The input voltage to the Arduino/Genuino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.
3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
GND. Ground pins.
IOREF. This pin on the Arduino/Genuino board provides the voltage reference with which the microcontroller operates. A properly configured shield can read the IOREF pin voltage and select the appropriate power source or enable voltage translators on the outputs to work with the 5V or 3.3V.

2007 UNO FLASH Electronic Mattel Sounds Lights Card Game Sealed Cards - Works 4.5 out of 5 stars (8) 8 product ratings - 2007 UNO FLASH Electronic Mattel Sounds Lights Card Game Sealed Cards - Works. UNO® is the classic card game that’s easy to pick up and impossible to put down! Players take turns matching a card in their hand with the current card shown on top of the deck either by color or number. Special action cards deliver game-changing moments as they help you defeat your opponents.

Uno Flash Hand Card

The power pins are as follows: Flash

Uno Flash Card Game

Vin. The input voltage to the Arduino/Genuino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.
3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
GND. Ground pins.
IOREF. This pin on the Arduino/Genuino board provides the voltage reference with which the microcontroller operates. A properly configured shield can read the IOREF pin voltage and select the appropriate power source or enable voltage translators on the outputs to work with the 5V or 3.3V.