TTL Barcoder

Generate and decode binary barcodes over TTL signals to synchronize multiple data acquisition systems.

→ Full documentation Barcodes encode a timestamp or random value as a sequence of timed HIGH/LOW pulses, transmittable over any digital output.

Quick Start

from ttl_barcoder.core import BarcodeTTL, BarcodeConfig, TTLType, TimestampPrecision

# Timestamp barcode (default) — encodes current time at ms precision
barcoder = BarcodeTTL()
sequence = barcoder.get_sequence()   # [(level: bool, duration_ms: float), ...]

# Random barcode
config = BarcodeConfig(ttl_type=TTLType.random, barcode_bits=32)
barcoder = BarcodeTTL(config)
sequence = barcoder.get_sequence()

Bpod

from ttl_barcoder.core import BarcodeTTL
from ttl_barcoder.hardware.bpod import inject_barcode_states

barcoder = BarcodeTTL()
sequence = barcoder.get_sequence()
inject_barcode_states(sma, sequence, bnc_channel='BNC1', first_state_name='send_sync', last_state_name='next')

Raspberry Pi GPIO

from ttl_barcoder.hardware.pigpio import send_barcode_sequence

send_barcode_sequence(barcoder.get_sequence(), pin=18)

Installation

pip install ttl-barcoder          # core only
pip install ttl-barcoder[bpod]    # + Bpod
pip install ttl-barcoder[pigpio]  # + Raspberry Pi GPIO

Configuration

BarcodeConfig is a Pydantic model — all fields are validated on construction.

from ttl_barcoder.core import BarcodeConfig, TTLType, TimestampPrecision

config = BarcodeConfig(
    ttl_type=TTLType.timestamp,            # or TTLType.random
    barcode_bits=37,                        # 16–64 bits
    timestamp_precision=TimestampPrecision.milliseconds,  # s / ms / us
    bit_duration_ms=35.0,
    init_duration_ms=10.0,
    tolerance=0.25,
)

Presets: default, high_speed, conservative, high_precision, random

from ttl_barcoder.core import get_preset
config = get_preset("conservative")

Preset	Bits	Precision	Bit duration	TX duration	Coverage
default	37	ms	35 ms	1355 ms	4.4 yr
high_speed	32	ms	25 ms	848 ms	49 days
conservative	37	ms	50 ms	1940 ms	4.4 yr
high_precision	42	us	50 ms	2190 ms	51 days

Architecture

ttl_barcoder/
├── core/
│   ├── config.py        # BarcodeConfig (Pydantic), TTLType, TimestampPrecision
│   ├── generator.py     # TTLGenerator ABC → TimestampGenerator / RandomGenerator
│   ├── encoder.py       # bits → (level, duration_ms) timing sequence
│   ├── decoder.py       # edge timestamps → barcode value
│   └── barcode_ttl.py   # BarcodeTTL — main interface combining the above
└── hardware/
    ├── bpod/            # Bpod StateMachine integration
    └── pigpio/          # Raspberry Pi GPIO via pigpio

• The generator is selected via a factory (create_generator(config)) based on TTLType.
• TimestampGenerator quantizes Unix time at the configured precision
• RandomGenerator draws from a numpy RNG. Both share the same encode_bits / max_value interface on the TTLGenerator base class.

Examples

• examples/dry_simulation.py — full walkthrough, no hardware needed
• examples/bpod_loopback.py — Bpod StateMachine with loopback test
• examples/pigpio_send.py — Raspberry Pi GPIO transmission

Contributing

1. Fork and create a feature branch
2. Add tests for new functionality
3. Run pytest
4. Submit a pull request

Acknowledgments

• Based on barcode synchronization from University of Colorado ONE Core
• Inspired by Open Ephys protocols
• Built for the neuroscience and scientific DAQ community

License & sources

This software is released under the BSD 3-Clause License.