Coldbox/Tessie Python Library via MQTT

This Python library allows you to control the Coldbox/Tessie system via the MQTT protocol.

Installation

Ensure you have the paho-mqtt library installed:

pip install paho-mqtt

Usage

You can either:

1. Import the library into another script and use it programmatically.
2. Use it interactively in a Python shell.

Example interactive usage:

python
from coldbox import *

box = Coldbox('your_mqtt_broker_address')
print(box.tecall.getTemp())  # Retrieve all temperatures

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Classes Overview

Tessie

The Tessie class facilitates communication with the MQTT broker and provides methods to interact with the system.

Attributes

• broker (str): MQTT broker address.
• port (int): MQTT broker port (default is 1883).
• topic (str): MQTT topic to subscribe to.
• _client (mqtt_client.Client): Paho MQTT client instance.
• waiting (list): Variables awaiting responses.
• found (list): List of received variables and their corresponding values.

Methods

• __init__(broker): Initializes the MQTT client, connects to the broker, and subscribes to the topic.
• on_connect(client, userdata, flags, rc): Callback for successful broker connection.
• _connect_mqtt(): Establishes connection to the MQTT broker.
• decode_msg(msg): Decodes and processes received MQTT messages.
• on_message(client, userdata, msg_recv): Callback for handling received MQTT messages.
• _subscribe(): Subscribes to the MQTT topic.
• _wait_for_var(var): Waits for a specific variable's response.
• get(var, args=""): Retrieves a variable's value.
• set(var, data, args=""): Sets a variable's value.
• cmd(cmd, args="", answer=False): Sends a command.
• help(): Sends a help request.

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Valve

The Valve class represents a controllable valve.

Methods

• __init__(tessie, i): Initializes the valve with a Tessie instance and index.
• set(value): Sets the valve to "on" (1) or "off" (0).
• get(): Retrieves the current state (1 for "on", 0 for "off").

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Env (Environment)

The Env class provides access to environmental data.

Methods

• __init__(tessie): Initializes the environment instance.
• getRH(): Returns relative humidity as a float.
• getDP(): Returns dew point as a float.
• getTempAir(): Returns air temperature as a float.
• getTempWater(): Returns water temperature as a float.
• getVprobe(number): Returns voltage probe data as a list of floats.

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TEC (Thermoelectric Cooler)

The TEC class represents a TEC device with operational and configuration methods.

Methods

• __init__(tessie, i): Initializes the TEC instance.
• pon(): Powers on the TEC.
• poff(): Powers off the TEC.
• getState(): Returns power state as a list of booleans.
• getTemp(): Retrieves the TEC temperature.
• getUI(): Retrieves voltage and current data.
• setTemp(temp): Sets the TEC's target temperature.
• setVoltage(u): Sets the control voltage.
• getVoltage(): Retrieves the control voltage.
• reset(): Reboots the TEC.
• loadFromFlash(): Loads stored variables from flash memory.
• getSWVersion(): Retrieves the software version.

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ConfTEC

The ConfTEC class handles TEC configuration settings.

Methods

• __init__(tessie, i): Initializes the TEC configuration.
• saveToFlash(): Saves configuration to flash memory.
• getPID(): Retrieves PID control constants [kp, ki, kd].
• setPID(kp, ki, kd): Sets PID control constants.
• getPIDMinMax(): Retrieves PID output range [min, max].
• setPIDMinMax(min, max): Sets PID output range.
• setRef(ref): Sets reference temperature.
• getRef(): Retrieves reference temperature.
• setMode(mode): Sets TEC operating mode.
• getMode(): Retrieves TEC operating mode.
• clearError(): Clears TEC errors.
• getError(): Retrieves TEC error codes.

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Coldbox

The Coldbox class aggregates multiple TECs, valves, and environmental sensors into a single interface.

Attributes

• valve0 / valve1: Valve instances.
• tecall: Master TEC instance for all TECs.
• tec1-tec8: Individual TEC instances.
• env: Environmental sensor instance.

Methods

• __init__(broker): Initializes the Coldbox with a specified MQTT broker.
• help(): Sends a help request to the Tessie system.

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Example Code

def main():
    # Initialize Coldbox with broker address
    box = Coldbox('coldbox02.psi.ch')

    # Get temperature from TEC 1
    print(f"TEC1 Temperature: {box.tec1.getTemp()} °C")

    # Turn on TEC 2
    box.tec2.pon()

    # Set TEC 3 target temperature
    box.tec3.setTemp(25.0)

if __name__ == "__main__":
    main()

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