No description, website, or topics provided.
Other R
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

Connected Seeds' sensor unit

Nanda Khaorapapong


As part of a research into how Internet of Things and sensor technologies can benefit an urban food growing community in London, this Connected Seeds (CS) sensor unit is designed for outdoor monitoring weather and plant growing conditions. It measures 7 parameters hourly (i.e. luminosity, barometric pressure, air temperature and humidity, soil temperature and humidity and approximated voltage level of the power supply), all of which are stored in an SD card and uploaded to an cloud server Thingspeak channels via 3G communication once a day.

Required hardware:

See component list

Required software:

Circuit Building and Installation:

  1. Prepare CS shields – download PCB design files (i.e. L2 and L4) and print each as a double-sided shield. See PCB design note for details.

  2. Assemble – Solder components on both shields and assemble a 4-layer circuit. See Assemble note for details.
    A fully assembled CS sensor circuit:

  3. Download and install all required libraries into Arduino/library folder

  4. Download the zip folder of CS_sensorUnit software, unzip and open CS_sensorUnit.ino file in Arduino or other preferred IDE

  5. Create a channel on Thingspeak with 7 fields; copy the channel's API write key to replace the 16-digit key on line 153 in CS_sensorUnit.ino file

  6. Upload software: set two slide switches on the top shield at 'usb' positions before uploading CS_sensorUnit software onto Arduino Mega board. Set both switches back at 'serial' positions once the uploading process is completed.

  7. Switch on the circuit

  8. Place all of the components in the enclosure and install it half way into the soil. Make sure the upper SHT10 sensor is exposed to air.

    A fully assembled CS sensor unit with two STH10 sensors on the side:


  • How it works – On start up, MCU is put into sleep mode and only wakes up by 2 alarms to perform series of events:
    • Alarm 1 wakes up MCU @ minute zero of every hour. This is to read, do a simple stat and store all data including alarm event in text files before entering sleep mode.
    • Alarm 2 wakes up MCU @ 23:10 every day to upload data to ThingSpeak and record alarm and 3G communication events in text files. After that, it checks 3G shield's power state and attempts to power it off (several times since the 3G shield is having issue with its power on/off feature of the original hardware). Before going into sleep mode, it sends out an sms notification to two phone numbers if the sensed voltage is lower than the mininum threshold.


The work is still under development. Though it is fully functional, several elements regarding both hardware and software can be improved. I will be very grateful if some parts or the entire system can be beneficial to your research or practice or play, and/or if you like to help improve. If so, please feedback using a contributing template or drop me a line at



Copyright (c) 2018 Nanda Khaorapapong and Connected Seeds
GNU GPLv3 license