Python/MicroPython Sensor Logger: Seamlessly Store Sensor Data in Google Sheets

A robust system for recording sensor values directly into a Google Sheet. It uses simple HTTP requests to bridge your micro‑controller with a lightweight server, and the gspread library to write the data.

Before you begin, follow the OAuth2 setup instructions on the gspread documentation to grant your script access to the target spreadsheet.

Hardware connections

• D0 to RST: Required to wake the board from deep‑sleep.
• + to 3.3 V on the Wemos.
• – to GND on the Wemos.
• Signal to A0 on the Wemos.

If you run into any issues, drop a comment and I’ll help you troubleshoot.

Schematics

Code

import machine
import urequests
import time

# RTC handles deep‑sleep wake‑ups
rtc = machine.RTC()
rtc.irq(trigger=rtc.ALARM0, wake=machine.DEEPSLEEP)

# ADC pin for sensor voltage
adc = machine.ADC(0)

######################
# Sensor calibration #
######################
# Reference values (inverse ×1000)
# Dry air  = 759  (0 %) → 1.31752305665349143610013175231
# Water    = 382  (100 %) → 2.61780104712041884816753926702
# Difference = 1.30027799046692741206740751471
# 1 % relative humidity = 0.0130027799046692741206740751471

hours = str(time.localtime()[3])
mins  = str(time.localtime()[4])
secs  = str(time.localtime()[5])
if int(secs) < 10: secs = '0' + secs
if int(mins) < 10: mins  = '0' + mins
timestr = f"{hours}:{mins}:{secs}"

# Convert ADC reading to relative humidity (%)
variable = (((1 / adc.read()) * 1000) / 0.0130027799046692741206740751471) - 101
variable = max(0, min(100, variable))

# Send data to local endpoint
url = 'https://192.168.1.2:8000/solomon'
headers = {'content-type': 'application/json'}
data = f'{{"Value":"{variable}","Time":"{timestr}"}}'
resp = urequests.post(url, data=data, headers=headers)
print(resp.json())

# Schedule next reading after 25 s and enter deep‑sleep
rtc.alarm(rtc.ALARM0, 25000)
machine.deepsleep()

Source: Python/MicroPython Sensor Logger for Google Sheets