IoT and devices (pyzed.iot)

Services that talk to devices: boards on a serial port, MQTT brokers, WebSockets, UDP and TCP sockets, Modbus PLCs and meters, Bluetooth LE gadgets and what answers on the local network. They work like the services: handlers go in on_<event>=, the connection runs in a thread of its own and events reach the handlers on the app’s thread. In Pyzed Design they are the components of the IoT category. See the IoT guide.

board = pz.SerialPort(match="arduino", baud_rate=115200, on_line=self.reading)
board.connect()

mqtt = pz.MqttClient("broker.local", subscribe="home/#", on_message=self.received)
mqtt.connect()
mqtt.publish("home/lamp/set", "on")

Every connection has connect(), disconnect(), connected, running and the events connected, disconnected and failed; with reconnect (milliseconds) it comes back by itself.

Serial ports

SerialPort

class SerialPort

A serial or USB serial port (Arduino, ESP32, Pico, GPS…): port names it ("COM3", "/dev/ttyUSB0") or, empty, the first one match names ("arduino", "2341:0043"; empty: the first USB port). Raises data (bytes) and line (text); write(), send_line(), reset() (DTR), set_baud_rate(). SerialPort.ports(match) lists the ports. Opens the device again when it comes back (reconnect, 1000 ms by default).

SerialWatcher

class SerialWatcher

Notices serial devices being plugged in and unplugged, every interval milliseconds: plugged and unplugged with a PortInfo (name, kind, vid, pid, usb_id, manufacturer, product, description), change with the list; ports is the last list.

Messages and sockets

MqttClient

class MqttClient

An MQTT 3.1.1 client (Mosquitto, Home Assistant, EMQX…): publish(topic, payload, qos, retain), subscribe(topic), unsubscribe() and on_topic(pattern, handler) with the wildcards + and #. Each message raises message with an MqttMessage (topic, payload, text, value, json()); last keeps the last one of each topic. TLS, logins, QoS 0, 1 and 2, a last will, and the subscriptions kept after every reconnection (2000 ms by default).

WebSocket

class WebSocket

A WebSocket client (ws://, wss://): send() text, bytes or JSON; each message raises message (text, bytes or, with json=True, the parsed data). headers, protocols, a ping every ping_interval milliseconds.

UdpSocket

class UdpSocket

Sends and receives UDP datagrams: start() listens on port, each one raises message with a UdpMessage (data, text, json(), host, port); send(data, host, port), reply(message, data), broadcast and multicast_group.

TcpClient

class TcpClient

A TCP connection (optionally TLS) to a device or server: raises data and line; write() and send_line().

Industrial

ModbusClient

class ModbusClient

A Modbus client over TCP (host) or RTU (serial_port, RS-485): read_coils, read_discrete_inputs, read_holding_registers, read_input_registers, read(table, address, format) ("float32", "int32"…), write_coil, write_register, write_coils, write_registers and write(address, value, format). poll lines (name table address [format] [count]) are read every interval milliseconds and raise update with a dict. Raises ModbusError when the device refuses or does not answer.

Discovery and Bluetooth

DeviceDiscovery

class DeviceDiscovery

Finds the devices of the local network with mDNS/Bonjour (service: "_http._tcp", "_esphomelib._tcp"…; empty: all) and SSDP/UPnP: scan(), start(); raises found and lost with a Device (name, host, port, address, kind, service, hostname, properties, url), change and done. pyzed.iot.resolve_local("esp32.local") finds one address.

BluetoothScanner

class BluetoothScanner

Finds Bluetooth LE devices nearby for timeout milliseconds, filtered by match (name or address) and services: scan(), start(), devices (nearest first); raises found with a BleDevice (address, name, rssi, uuids, manufacturer_data), change, done and failed. Needs pip install "pyzed-ui[bluetooth]" (bleak).

BluetoothDevice

class BluetoothDevice

A connection to one Bluetooth LE device by address or name: read(uuid), write(uuid, data, response), subscribe(uuid), services(); the characteristics in notify raise notification with a BleNotification (uuid, data, text, value). UUIDs can be short ("2a37") or names ("heart_rate_measurement", "battery_level", "nordic_uart_tx").