Make an IoT Thermometer using Zerynth (Python for Microcontrollers)

• Tweet
• Pin It

Web site:

Project Summary:

In this tutorial, we’re going to see how to develop a simple but powerful IoT Thermometer, using a Zerynth-powered single-board microcontroller and Zerynth App as the remote display.

Full Project:

Zerynth App is a mobile application for Android and iOS that allows fast prototyping of graphical interfaces for your IoT projects.

With Zerynth App you can turn any mobile into the controller and display for smart objects and IoT systems! In particular, you can manage and control the connected devices programmed with Zerynth, enabling a bidirectional communication channel between them and your mobile.

In this tutorial, we’re going to see how to develop a simple but powerful IoT Thermometer, using a Zerynth-powered single-board microcontroller and Zerynth App as the remote display.

Required materials

First of all, you need a board. You can select one of the 32-bit microcontroller devices supported by Zerynth. We’ve chosen the Flip&Click by Mikroelektronika, that shares many of the same attributes as the popular Arduino platforms, including the 32-bit AT91SAM3X8E by Microchip, the core of Arduino Due.

To measure the temperature we’ve picked the Temp&Hum Click, that carries an HTS221 temperature and relative humidity sensor.

To connect the board to internet we’ve chosen the WiFi PLUS Click, that features MRF24WB0MA – 2.4GHz, IEEE std. 802.11 – compliant module from Microchip, as well as MCW1001 companion controller with on-board TCP/IP stack and 802.11 connection manager.

Last but not least, you need:

• Zerynth Studio, a powerful IDE for embedded programming in Python that enables the IoT. You can download it here.
• Zerynth App. You can download it here.

Assembling your IoT Thermometer

Flip&Click is Arduino’s two-sided cousin. On one side it’s an Arduino. But on the other side, you’ll find four open mikroBUS sockets for what the company calls “click boards.” Essentially, these are add-on modules that resemble Arduino shields, but shrunken down so that you can fit a few at the same time on the Flip & click without any trouble. Just add the Temp&Hum and the Wifi Plus clicks to the board, respectively at the slot A and B.

How to program the IoT Thermometer using Python

Clone the example

Once you have installed Zerynth Studio and created a Zerynth user, you can clone the example “Zerynth App Oscilloscope“. Take a look here to learn how to clone an example.

Let’s take a look at the original code in the “main.py” file: here is where you develop the logic of your Python script. We’ll start from the original code and then we’ll edit the script to develop our specific project.

################################################################################
# IoT Thermometer
################################################################################

from wireless import wifi
# this example is based on Particle Photon
# change the following line to use a different wifi driver
from broadcom.bcm43362 import bcm43362 as wifi_driver
import streams
import adc

# Import the Zerynth APP library
from zerynthapp import zerynthapp

streams.serial()

sleep(1000)
print("STARTING...")

try:
    # Device UID and TOKEN can be created in the ADM panel
    zapp = zerynthapp.ZerynthApp("DEVICE UID", "DEVICE TOKEN", log=True)

    # connect to the wifi network (Set your SSID and password below)
    wifi_driver.auto_init()
    for i in range(0,5):
        try:
            wifi.link("SSID",wifi.WIFI_WPA2,"PASSWORD")
            break
        except Exception as e:
            print("Can't link",e)
    else:
        print("Impossible to link!")
        while True:
            sleep(1000)

    # Start the Zerynth app instance!
    # Remember to create a template with the files under the "template" folder you just cloned
    # upload it to the ADM and associate it with the connected device
    zapp.run()

    # Read ADC and send values to the ADM
    while True:
        sleep(1000)
        x = (adc.read(A4)*100)//4096
        zapp.event({"data":x})
        if x>95:
            # send mobile notification
            # (there is a limit of one notification per minute per device on the ADM sandbox)
            zapp.notify("ALARM!","The value is greater than 95!")

except Exception as e:
    print(e)

################################################################################
# Zerynth App Oscilloscope
################################################################################

from wireless import wifi
from microchip.mcw1001a import mcw1001a as wifi_driver
import streams
import adc

streams.serial()

# Import the Zerynth APP library
from zerynthapp import zerynthapp

# Import the HTS221 library
from stm.hts221 import hts221

temp_hum = hts221.HTS221(I2C0, D21) # slot A

sleep(1000)
print("STARTING...")

try:
    # Device UID and TOKEN can be created in the ADM panel
    zapp = zerynthapp.ZerynthApp("DEVICE UID", "DEVICE TOKEN",ip = "178.22.65.123", log=True)

    # connect to the wifi network (Set your SSID and password below)
    wifi_driver.init(SERIAL2,D24) # slot B
    for i in range(0,5):
        try:
            wifi.link("SSID",wifi.WIFI_WPA2,"PASSWORD")
            break
        except Exception as e:
            print("Can't link",e)
    else:
        print("Impossible to link!")
        while True:
            sleep(1000)

    # Start the Zerynth app instance!
    # Remember to create a template with the files under the "template" folder you just cloned
    # upload it to the ADM and associate it with the connected device
    zapp.run()
    
    # Read the sensor and send values to the ADM
    while True:
        sleep(1000)
        tmp, hum = temp_hum.get_temp_humidity() # Read tmp and hum
        print("Temp is:", tmp, "Humidity is:", hum)
        try:
            zapp.event({"data":tmp})
        except Exception as e:
            print(e)
        if tmp>30:
            # send mobile notification
            # (there is a limit of one notification per minute per device on the ADM sandbox)
            try:
                zapp.notify("ALARM!","High Temperature!")
            except Exception as e:
                print(e)
        
except Exception as e:
    print(e)

Remember that “DEVICE UID”, “DEVICE TOKEN”, “SSID” and “PASSWORD” have to be edited to fit with your own parameters.

At this point, you can uplink the script into your device.

How to see the IoT Thermometer dashboard on the Zerynth App

As you can read in this very brief tutorial, you have just to open the Zerynth App, log-in and select the specific device to see your IoT Thermometer dashboard. Last, Zerynth App can also receive push notifications from the connected devices. In this case, a notification will appear when the temperature will be greater than the threshold!

If you have any questions don’t hesitate to open a discussion in the Zerynth community forum.

Enjoy!