def record_pcap(hostname: str,
lidar_port: int = 7502,
imu_port: int = 7503,
n_seconds: int = 10) -> None:
"""Record data from live sensor to pcap file.
Note that pcap files recorded this way only preserve the UDP data stream and
not networking information, unlike capturing packets directly from a network
interface with tools like tcpdump or wireshark.
See the API docs of :py:func:`.pcap.record` for additional options for
writing pcap files.
Args:
hostname: hostname of the sensor
lidar_port: UDP port to listen on for lidar data
imu_port: UDP port to listen on for imu data
n_seconds: max seconds of time to record. (Ctrl-Z correctly closes
streams)
"""
import ouster.pcap as pcap
from datetime import datetime
# [doc-stag-pcap-record]
from more_itertools import time_limited
# connect to sensor and record lidar/imu packets
with closing(client.Sensor(hostname, lidar_port, imu_port,
buf_size=640)) as source:
# make a descriptive filename for metadata/pcap files
time_part = datetime.now().strftime("%Y%m%d_%H%M%S")
meta = source.metadata
fname_base = f"{meta.prod_line}_{meta.sn}_{meta.mode}_{time_part}"
print(f"Saving sensor metadata to: {fname_base}.json")
source.write_metadata(f"{fname_base}.json")
print(f"Writing to: {fname_base}.pcap (Ctrl-C to stop early)")
source_it = time_limited(n_seconds, source)
n_packets = pcap.record(source_it, f"{fname_base}.pcap")
print(f"Captured {n_packets} packets")
def plot_imu_z_accel(hostname: str,
lidar_port: int = 7502,
imu_port: int = 7503,
n_seconds: int = 5) -> None:
"""Plot the z acceleration from the IMU over time
Args:
hostname: hostname of the sensor
imu_port: UDP port to listen on for imu data
n_seconds: seconds of time to take a sample over
"""
import matplotlib.pyplot as plt # type: ignore
# [doc-stag-imu-z-accel]
from more_itertools import time_limited
# connect to sensor and get imu packets within n_seconds
source = client.Sensor(hostname, lidar_port, imu_port, buf_size=640)
with closing(source):
ts, z_accel = zip(*[(p.sys_ts, p.accel[2])
for p in time_limited(n_seconds, source)
if isinstance(p, client.ImuPacket)])
# initialize plot
fig, ax = plt.subplots(figsize=(12.0, 2))
ax.plot(ts, z_accel)
# [doc-etag-imu-z-accel]
plt.title("Z Accel from IMU over {} Seconds".format(n_seconds))
ax.set_xticks(np.arange(min(ts), max(ts), step=((max(ts) - min(ts)) / 5)))
# add end ticker to x axis
ax.set_xticks(list(ax.get_xticks()) + [max(ts)])
ax.set_xlim([min(ts), max(ts)])
ax.set_ylabel("z accel")
ax.set_xlabel("timestamp (ns)")
ax.ticklabel_format(useOffset=False, style="plain")
plt.show()