30  Assignment 2

30.1 Some guidelines

In this project each one of you will individually create a Thingspeak channel and will upload to it data from an ESP32.

Minimal requirements:

  • Measure temperature (using SHT31)
  • Measure humidity (using SHT31)
  • Calculate VPD

30.2 Deadline

All Chanels must be live in two weeks from the day you hear about it in class.

The name of the channel MUST be spelled with the prefix “Assignment2_” and then your first and last name with separated by an underscore.
For example: Assignment2_Erez_Feuer

You MUST provide information regarding your channel in the “description” section which can be found under “channel settings”. This information should include:

  • location (e.g.: balcony in Rechovot, kitchen in Gan-Yavne, 7th floor bedroom window, etc.),
  • what the sensors are measuring, and
  • any other information that you find relevant - the more the better.

Upload interval should be every 5 minutes.

30.3 Public view

We will be monitoring your Thingspeak channels via the “Public view” section. It is very simple to make your channel public, just check “Share channel view with everyone” under the Sharing tab as you can this in the following image:

30.4 How to power your projects

Once the code is uploaded to the ESP32 and every thing works fine, you don’t need your computer anymore, and can use a generic USB charger as a power supply. Don’t worry about the code, it will work as long as the ESP32 has power, because you already uploaded the code to memory.

30.5 Calculate VPD

The Vapor Pressure Deficit (VPD, in kPa) is the difference between saturation vapor pressure \(e_s\) and actual vapor pressure \(e_d\):

\[\text{VPD} = e_s - e_d.\]

For temperatures ranging from 0 to 50 °C, the saturation vapor pressure can be calculated with

\[ e_s = \exp \left[ \frac{16.78\, T -116.9}{T+237.3} \right], \]

and the actual vapor pressure is given by

\[ e_d = e_s \frac{RH}{100}, \]

where \(RH\) is the relative humidity (%), and the temperature \(T\) in the equations above is in degrees Celcius.

30.6 Circuit diagram

As part of the project, you will draw the circuit diagram using the following website:
https://www.circuit-diagram.org/editor/
Save the diagram as a png and upload it to moodle.