Blackjack Secret Card Counter

This project turns your Adafruit Circuit Playground Bluefruit into a smart blackjack card counting tool!

Counting cards is a method used by skilled players to keep track of the ratio of high to low cards left in the deck during a game of blackjack.

By doing this, players can adjust their bets and playing strategy when the odds are in their favor.Using just the built-in buttons, lights, and motion sensors, you can:

1. Tally cards (+1, 0, -1)
2. Track decks in play
3. Auto-calculate true count
4. Get real-time tilt feedback with colored lights
5. Know when to adjust your bets without anyone noticing!

It’s stealthy, educational, and perfect for learning CircuitPython basics and game strategy!

Adafruit Circuit Playground Bluefruit

Micro-USB cable (for programming and power)

Computer with CircuitPython and PyCharm installed (easy Adafruit setup)

Battery pack (for portable use at the table!)

Paste the attached code into the code.py file of your Bluefruit device.

You will need to install the libraries adafruit_lis3dh and neopixel to utilize movement of the Bluefruit and the lights on the Bluefruit, respectively.

Here are instructions of how the code will let you interact with the Bluefruit.

Action What Happens

Press Button A Adds +1 to tally

Press Button B Adds 0 to tally (still counts a card)

Press Both A + B together Subtracts -1 from tally

Hold A for 3 seconds Enter "Deck Entry Mode" to set number of decks

Hold B for 3 seconds Reset tally, decks, and card count to default

Tilt board sharply Display True Count + Light up LEDs

Explanatory Youtube Video

How It Works

1. Low cards (2, 3, 4, 5, 6) are good for the dealer.
2. → You add +1 to your count when you see them.
3. High cards (10, Jack, Queen, King, Ace) are good for the player.
4. → You subtract -1 from your count when you see them.
5. Middle cards (7, 8, 9) are neutral.
6. → You add 0 when you see them.

Running Count vs True Count

1. The Running Count is your current total based on cards you've seen so far.
2. The True Count adjusts the Running Count based on how many decks are still left.

True Count Formula: True Count = Running Count ➗ Remaining Decks

True Count gives a more accurate idea of your advantage — especially important when multiple decks are used!

Why It Matters

1. When the True Count is high (positive), more high cards are left.
2. → Player advantage! Increase your bets!
3. When the True Count is low (negative), more low cards are left.
4. → Dealer advantage. Lower your bets or even sit out.

How It Works

1. Keep a simple +1 / 0 / -1 tally as cards are played.
2. Tilt the device to quickly check your True Count and know when to bet big.
3. Practice makes perfect — counting fast and adjusting in real-time is the goal!

Lights

Red Lights = Bad true count (negative count, disadvantageous)

Yellow Light = Neutral (small positive, or zero)

Green Lights = Good true count (high positive, betting opportunity!)

More lights = Stronger count value (positive or negative)

Here’s how to practice:

1. Set the number of decks (default is 6, change if needed by holding Button A).
2. Tap Button A/B during a simulated game to represent cards seen.
3. Tilt the board:
4. View the current True Count, Tally, and Remaining Decks on the console.
5. Instantly read light colors:
6. Green → Raise your bets!
7. Yellow → Normal play.
8. Red → Play cautiously or reduce bets.

Watch the lights change dynamically as you count more cards!

Hold steady while pressing A or B to avoid accidental tilts.

Place middle knuckle and tip of thumb on A and B buttons to avoid hitting the "reset" button in between the two while inputting a -1 tally.

Tilt only briefly to check the count (the lights and readout will only update once per second).

Reset often if starting a new shoe.

Stay subtle: Hide the board in a pocket, under a jacket or on your lap when using it in real games! 😉

Practice offline with a deck of cards to get faster at inputting.