Quick Start, Set up a LabRat and Logging Inator

Quick Start, Set up a LabRat and Logging Inator#

This is a guide to get startd logging with LabRat and a Inator logging device.

Requirements

  1. A computer with Python installed

  2. A microprocessor (we are using a Pico W which has built in Wifi)

  3. A DHT11 temperature and humidity sensor (we used the version from Seeed Studios)

The first step is to set up the Inator to log data from. We will make a DHT_Inator in this example where we connect a DHT11 Temperature and Humidity Sensor to our Pico. But everything here can be applied to any sensor you would like to use.

Logger set up#

To set up the pico as a logger follow the instructions in the tutorial to install the CircuitPython firmware

The next step is to connect the DHT sensor.

LabRat/images/rat-quick_1.png

Make the following connections:

DHT11 Pin

Pico Pin

GND

GND

VCC

3.3V out

NC

Not connected

SIG

GPO1

Next we will set some test code on the Pico to connect to the DHT11.

A library is required, it is not included in the core CircuitPython package you uploaded to the Pico but can be very easily added using the instructions here.

import time
import board
import adafruit_dht

dht = adafruit_dht.DHT11(board.GP0)

while True:
    try:
        temp = dht.temperature
        humidity = dht.humidity
        print(f"Temperature: {temp} C \t Humidity: {humidity}%")
    except RuntimeError as e:
        print("Reading from DHT failure: ", e.args)
    time.sleep(5)

This should print the temperature and humidity recorded by the DHT11 to your serial connection. For more info on how to connect the Pico to serial and upload code the instructions are here.

LabRat set up#

THe next step is to install the LabRat control and logging software

Go to the repo[inator-project/LabRat] and download the repo contents, either use Git or just download the zip.

The first step is to install the necessary Python libraries. Files for installation from pip or conda (or mamba) are in the installation folder

conda env create -f environment.yml

pip install -r /path/to/requirements.txt

If you now run

python labrat_log.py -h

You should get something like the following

Readying Logging at:2026-02-21T16:17:47+00:00
usage: labrat_log.py [-h] [-sql SQL] [-secrets SECRETS] [-setupsql] [--createdb] [--dev_file DEVFILE] [-file FILE]
                     [--setfile] [-ser_port SER_PORT] [-baud BAUD]
                     CONN

Purpose: Connect sensors and log to DB

positional arguments:
  CONN                Which connection will be monitored. Can be mqtt for a MQTT connectionserial for a wired Serial
                      Connection or flask for a Flaks based API

options:
  -h, --help          show this help message and exit
  -sql SQL            The SQL database path. Should be absolute
  -secrets SECRETS    The path to the toml fil with secrets, such as log ins are kept
  -setupsql           If added this flag will run the create Inator DB function.This will then require extra flags
                      such as the device info file location
  --createdb          If setup flag added this will create a new DB if the given db doesn't exist
  --dev_file DEVFILE  If the setup flag is added this will load the device informationThis is the path to the JSON
                      file that contains the deviceinformation to be loaded into the SQL
  -file FILE          If set this is the file path to a text file where data can be logged.Should be an absolute path
  --setfile           If set this will run a set up file function, for headers etc...
  -ser_port SER_PORT  The COM port to connect to for serial
  -baud BAUD          The Baud rate for the serial connection

Connecting it together#

Now we will combine the logging Pico with the LabRat programme to save data from a sensor into a sqlite database. There are several ways to make this connection. Choose which ever you prefer/need.

If we are connecting over serial we will use the following code on the pico

import os
import microcontroller
import time
import json
import board
import adafruit_dht

dht = adafruit_dht.DHT11(board.GP0)

#Retrieve variables from settings.toml
inatorname = os.getenv("INATORNAME")
accTime = os.getenv('ACQUIRETIME')  #how often to acquire and transmit data

while True:
    temp = dht.temperature
    humidity = dht.humidity
    #Create dictionary
    json_dict = {"inator":inatorname,"temperature":temp,"humidity":humidity}  # Send data with JSON syntax
    json_data = json.dumps(json_dict)
    print(f"{json_data}")
    time.sleep(accTime)

Where we would have the following settings.toml file saved on the pico. We shall call the Inator teminator_1 and acquire for 30 seconds

INATORNAME = "teminator_1"        # Name of the device, will be used when sending data (put name between the quote marks)
ACQUIRETIME = 30       # The value (in seconds) of how often to acquire data and log for

To add the inator to the database we need a device_info.json file

{
  "devices": [
    {
      "device_name": "teminator_1",
      "device_guid": "",
      "num_sensors": 2,
      "device_info": "Has DHT11 sensor",
      "device_type": "pico",
      "device_location": "TBD",
      "device_active": 1,
      "connection": "Serial",
      "sensors": [
        {
          "sens_name": "temperature",
          "measures": "Temperature",
          "returns": "Celsius",
          "calib": "1:1",
          "range": "0-50",
          "info": "Seeed DHT11 on GP0",
          "comments": "None"
        },
        {
          "sens_name": "humidity",
          "measures": "Humidity",
          "returns": "%",
          "calib": "1:1",
          "range": "0-100",
          "info": "Seeed DHT11 on GP0",
          "comments": "None"
        }
      ]
    }
  ]
}

The most important thing here is that the device_name and sens_name must match the names sent from the pico, otherwise the logging will fail It is also necessary to have A GUID set for the device. To generate this run

python -c "import uuid
print(uuid.uuid4())"

The next step is to find out which COM port the Pico is on.

On Windows go to the device manager and look under ports to see which COM port is connected

On linux

ls /dev/tty*

Will display a list of all tty devices. The pico will probably be either ttyAM0 or ttyAM1 if in doubt plug and unplug it. If you get permission errors run

sudo adduser <red-user> dialout

We can now (finally) set up the LabRat, run the following replacing with the COM port from above

python labrat_log.py -sql ./datalog.sql -setupsql --createdb --dev_file ./device_info.json -ser_port <PORT> -baud 11520 serial

This should start the programme, create the sqlite database, add tables for the teminator_1 device and then start listening on the serial port

When you need to run it again the command can be simplifed to:

python labrat_log.py -sql ./datalog.sql -ser_port <PORT> -baud 11520 serial

as the database exists and has the correct tables

We are now set up for logging

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