FlexTail developer workflow

Flex CLI example

Flex CLI connects to FlexTail over Bluetooth Low Energy or USB serial, then streams measurements, converts recordings, and calculates metrics without requiring a custom application.

1. Discover

Find an available sensor

Scan both transports automatically, or target BLE and USB serial individually when a workflow needs explicit device selection.

flex scan --transport auto

2. Stream

Send live data to Python through stdout

Run flex connect to stream raw CSV measurements directly into a Python script. This example parses each row with flexlib and calculates lumbar bend.

Stream command

flex connect | python analyze_live.py

analyze_live.py

import flexlib
import sys

for line in sys.stdin:
    measurement = flexlib.CSVReader.parse_string(line).measurements[0]
    lumbar_bend = measurement.angles.bend
    print(f"lumbar bend: {lumbar_bend:.1f}")

3. Publish

Forward live measurements to MQTT

Pipe the same stream into a small Python publisher to send every measurement to an MQTT topic. This example expects a broker on localhost:1883 and the paho-mqtt package.

Stream command

flex connect | python publish_mqtt.py

publish_mqtt.py

import csv
import json
import sys

import paho.mqtt.client as mqtt
from paho.mqtt.enums import CallbackAPIVersion

client = mqtt.Client(CallbackAPIVersion.VERSION2)
client.connect("localhost", 1883)
client.loop_start()

for sample in csv.DictReader(sys.stdin):
    client.publish("flextail/live", json.dumps(sample))

client.disconnect()
client.loop_stop()

4. Transform

Convert and inspect recordings

Batch workflows can export CSV, JSON, Arrow, Parquet, or RSF. Add angles and three-dimensional coordinates for downstream analysis, then emit posture and movement aggregates as JSON.

flex convert session.rsf session.parquet --angles --coordinates

flex stats session.csv --json

Python SDK path

Process captured packets directly

The bundled Python BLE example also accepts packet hex on stdin. This lower-level route is useful for replaying captured packets through the native FlexTail SDK without opening a Bluetooth connection.

cat captured_packets.hex | python examples/python/ble-stream/flex_ble_stream.py --stdin-hex --no-ble

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