Documentation

Setup Guide

Complete hardware wiring and software installation guide for your Autobowl system.

Step 0: Get the 3D Printed Parts

This project requires the Mini Tabletop Bowling 3D printed automatic pinsetter files from Kickstarter. All mechanical components are 3D printed — no additional hardware needed except the PCA9685 servo driver board.

View Kickstarter Project

Hardware Requirements

The only electronic component you need to purchase separately is the PCA9685 servo driver board. All other components (servos, sensors, LEDs) are included with the Kickstarter kit or are standard Raspberry Pi accessories.

Main Controller

Raspberry Pi 4

2GB+ RAM recommended
MicroSD card (16GB+)
USB-C power supply (5V 3A)
USB webcam (for pin detection)
HDMI display (optional, for kiosk mode)

PCA9685 PWM Board

16-channel, 12-bit PWM driver via I2C for reliable servo control

7 Servos

Deck raise, slide, scissors, sweep arms, ball return

Stepper Motor

Turret control with Hall effect sensor for homing

USB Webcam

For camera-based pin detection

Sensors

IR (pins), dual ball sensors (speed calc), Hall effect (home)

WS2812B LEDs

106 addressable RGB LEDs (4 strips) for lane & deck lighting

Servo Channel Mapping

Channel	Servo	Function
0	Slide	Deck forward/back movement
3	Scissors	Pin grab/release mechanism
5	Ball Return	Ball return door
9	Left Raise	Deck height (left side)
11	Right Raise	Deck height (right side)
13	Right Sweep	Lane sweep arm (right)
15	Left Sweep	Lane sweep arm (left)

Wiring Diagrams

                Raspberry Pi 4 GPIO Header
                ┌─────────────────────────┐
         3.3V ──│ 1                     2 │── 5V
(I2C SDA) GPIO2 │ 3  ← PCA9685 SDA     4 │── 5V
(I2C SCL) GPIO3 │ 5  ← PCA9685 SCL     6 │── GND
      GPIO4     │ 7                     8 │── GPIO14
          GND ──│ 9                    10 │── GPIO15
      GPIO17    │11                    12 │── GPIO18
      GPIO27    │13                    14 │── GND
      GPIO22    │15                    16 │── GPIO23 (Conveyor)
         3.3V ──│17                    18 │── GPIO24 (Ball Speed)
     (MOSI)     │19                    20 │── GND
     (MISO)     │21                    22 │── GPIO25 (Ball Trigger)
     (SCLK)     │23                    24 │── GPIO8
          GND ──│25                    26 │── GPIO7
       (ID_SD)  │27                    28 │── (ID_SC)
      GPIO5     │29                    30 │── GND
   Step GPIO6   │31                    32 │── GPIO12 (WS2812 LEDs)
Direction GPIO13│33                    34 │── GND
HallSensor GPIO19│35                    36 │── GPIO16
 IRSensor GPIO26│37                    38 │── GPIO20
          GND ──│39                    40 │── GPIO21
                └─────────────────────────┘

PCA9685 Board                    Raspberry Pi
┌────────────────┐              ┌──────────────┐
│      VCC       │──────────────│ 3.3V (Pin 1) │
│      GND       │──────────────│ GND  (Pin 6) │
│      SDA       │──────────────│ GPIO2 (Pin 3)│
│      SCL       │──────────────│ GPIO3 (Pin 5)│
│                │              └──────────────┘
│  V+ (Servo Pwr)│──── External 5V Power Supply (2A+ per servo)
│                │
│  Channel 0 ────│──── Slide Servo Signal
│  Channel 3 ────│──── Scissors Servo Signal
│  Channel 5 ────│──── Ball Return Servo Signal
│  Channel 9 ────│──── Left Raise Servo Signal
│  Channel 11 ───│──── Right Raise Servo Signal
│  Channel 13 ───│──── Right Sweep Servo Signal
│  Channel 15 ───│──── Left Sweep Servo Signal
└────────────────┘

Each servo connects:
• Signal (orange/yellow) → PCA9685 channel PWM pin
• VCC (red) → PCA9685 V+ rail
• GND (brown/black) → PCA9685 GND rail

Important: Do NOT power servos from Pi's 5V pins! Use an external 5V power supply (2A+ per servo) connected to V+ terminal. PCA9685 uses I2C address 0x40 by default.

Stepper Driver (A4988/DRV8825)      Raspberry Pi
┌──────────┐                       ┌──────────────┐
│   STEP   │───────────────────────│ GPIO6  (31)  │
│   DIR    │───────────────────────│ GPIO13 (33)  │
│   GND    │───────────────────────│ Any GND pin  │
│   VCC    │──── 5V Logic supply
│   VMOT   │──── Motor voltage (12-24V)
└──────────┘

Hall Effect Sensor (Turret Home)
┌──────────┐
│   VCC    │──── 3.3V (Pin 1 or 17)
│   GND    │──── GND
│   OUT    │───────────────────────│ GPIO19 (35)  │
└──────────┘     (internal pull-up enabled)

Raspberry Pi                    LED Strip Chain
┌──────────────┐
│ GPIO14 (8)   │───DATA──┐
│              │         │
│   GND        │───GND───┼────────────────────────────────────┐
└──────────────┘         │                                    │
                         ▼                                    │
              ┌─────────────────┐    ┌─────────────────┐     │
              │  LANE LEFT (41) │    │ LANE RIGHT (41) │     │
              │    DIN    DOUT  │───▶│    DIN    DOUT  │──┐  │
              │    5V     GND   │    │    5V     GND   │  │  │
              └─────────────────┘    └─────────────────┘  │  │
                                                          ▼  │
              ┌─────────────────┐    ┌─────────────────┐     │
              │ DECK LEFT (12)  │◀───│ DECK RIGHT (12) │     │
              │    DIN    DOUT  │    │    DIN    DOUT  │     │
              │    5V     GND   │    │    5V     GND   │     │
              └─────────────────┘    └─────────────────┘     │
                                                             │
              EXTERNAL 5V POWER SUPPLY (10A recommended) ────┘

Total: 106 LEDs (41 + 41 + 12 + 12)

Power Warning: 106 LEDs at full white can draw ~6.4A @ 5V (60mA per LED). Use 10A+ 5V power supply with adequate wire gauge (18 AWG or thicker). Connect GND from power supply to Pi GND. Must run with sudo for DMA access.

Ball Trigger Sensor (First sensor ball passes - starts timer)
┌──────────┐           Raspberry Pi
│   VCC    │──── 3.3V (Pin 1 or 17)
│   GND    │──── GND
│   OUT    │───────────│ GPIO25 (22)  │ (internal pull-up)
└──────────┘

Ball Speed Sensor (Second sensor - stops timer for velocity calc)
┌──────────┐
│   VCC    │──── 3.3V (Pin 1 or 17)
│   GND    │──── GND
│   OUT    │───────────│ GPIO24 (18)  │ (internal pull-up)
└──────────┘

  Sensor Placement (top view):
  ─────────────────────────────────────────────────
     BALL RETURN TRACK
  ─────────────────────────────────────────────────
       ↓ Ball Direction ↓

   [Trigger Sensor]  ────┐
         GPIO25          │ 12 inches (configurable)
                         │
   [Speed Sensor]    ────┘
         GPIO24

IR Sensor (Pin Detection)
┌──────────┐
│   VCC    │──── 3.3V
│   GND    │──── GND
│   OUT    │───────────│ GPIO26 (37)  │ (internal pull-up)
└──────────┘

Conveyor Motor Relay
┌──────────┐           ┌──────────────┐
│   VCC    │──── 5V (external or Pi Pin 2/4)
│   GND    │───────────│ Any GND pin  │
│   IN     │───────────│ GPIO23 (16)  │
│   COM    │──── Power supply (or INA226 CUR-)
│   NO     │──── Motor (+)
└──────────┘

The INA226 monitors conveyor power for blockade detection.
If power exceeds 14W (jam/obstruction), triggers emergency stop.

INA226 Board                     Raspberry Pi
┌──────────┐                    ┌──────────────┐
│   VCC    │────────────────────│ 3.3V (Pin 1) │
│   GND    │────────────────────│ GND  (Pin 6) │
│   SDA    │────────────────────│ GPIO2 (Pin 3)│ (shared with PCA9685)
│   SCL    │────────────────────│ GPIO3 (Pin 5)│ (shared with PCA9685)
│   A0     │────────────────────│ 3.3V (Pin 1) │ (sets address 0x41)
└──────────┘

Power Monitoring Wiring:
                    CUR+ ────────── Power Supply (+)
                      │
               ┌──────┴──────┐
               │   INA226    │
               │   [shunt]   │  Shunt: 0.002Ω (R002)
               └──────┬──────┘
                      │
                    CUR- ─┬──────── Relay COM
                          │
                     V+ ──┘         Relay NO ────── Motor (+)
                                                        │
                     V- ─────────── GND ◄───────── Motor (-)

I2C Address: 0x41 (configured via A0 pin to 3.3V)

Blockade Detection: Monitors power every 100ms with 200ms grace period after startup. If power exceeds 14W, triggers emergency stop disabling all hardware until cleared via UI.

Software Setup

Download Autobowl

Get the latest Autobowl software for your Raspberry Pi from our download page. Pre-built binaries are available for easy installation.

Go to Downloads

Configuration

Servo Calibration

Access the debug page at http://<raspberry-pi-ip>:8080/debug to:

Adjust servo positions with sliders (0-180°)
Test stepper motor movement
Monitor sensor values in real-time
Trigger LED animations (Strike, Comet, etc.)

Web Interface URLs

/Main scoreboard display

/new-gameStart a new game

/playersPlayer management

/debugHardware diagnostics

LED Animation Modes

offAll LEDs off

idleSolid white

strikeRed wipe → Flash → White

comet4-LED white comet

greenSolid green (fill ball)

Troubleshooting

PCA9685 Not Detected

Check I2C is enabled via sudo raspi-config
Scan I2C bus: i2cdetect -y 1
Should show device at address 0x40
Check SDA/SCL wiring (GPIO2/GPIO3)
Verify VCC (3.3V) and GND connections

Servos Not Moving

Verify PCA9685 is detected via I2C
Check external 5V power supply to V+ on PCA9685
Ensure common ground between Pi, PCA9685, and power supply
Test with debug page slider at /debug
Check logs for "PCA9685 initialized" message

WS2812 LEDs Not Working

Must run with sudo for DMA access
Check data pin connection (GPIO14, Pin 8)
Verify 5V power supply capacity (10A+ for 106 LEDs)
Check logs for "WS2812 initialized" message

Sensors Not Detecting

Check 3.3V power to sensor
Verify GND connection
Use debug page to view raw sensor values
Sensors use internal pull-ups (active LOW)
Test sensor output with multimeter

INA226 Not Detected

Scan I2C: i2cdetect -y 1 should show 0x40 (PCA9685) and 0x41 (INA226)
Check A0 pin is connected to 3.3V (sets address to 0x41)
Verify SDA/SCL wiring (shared with PCA9685)
Check 3.3V and GND connections
If power readings seem wrong, verify shunt is 0.002Ω (R002 marking)

False Blockade Triggers

The 200ms grace period should prevent startup triggers
Check if motor startup spike exceeds the grace period
Verify conveyor motor is not overloaded or stalled
Check power readings on debug page Conveyor Power panel
Logs show power readings: Power monitor reading

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