Luigi Francesco Cerfeda
Published © GPL3+

Real-Time Data Plotting of LoRa Nodes Using Python

In this article, we'll see how to get and visualize sensor data of LoRa nodes using Zerynth, The Things Network, and Matplotlib.

IntermediateFull instructions provided2 hours2,359

Things used in this project

Hardware components

MikroElektronika Flip&Click
×1
MikroElektronika LoRa Click
×1
MikroElektronika Temp&Hum Click
×1
RN2483
Microchip RN2483
×1

Software apps and online services

Zerynth Studio
Zerynth Studio
The Things Network
The Things Network

Story

Read more

Schematics

Zerynth and TTN - LoRa

Zerynth lora node data plotting k6asnjtvti

Code

LoraWAN sensor data Logging

Python
# LoraWAN sensor data Logging
 
import streams
from microchip.rn2483 import rn2483
from stm.hts221 import hts221
 
streams.serial()
 
try:
    rst = D16 # reset pin 
    # insert otaa credentials!
    appeui = "YOUAPPEUI"
    appkey =  "YOUAPPKEY"
    print("joining...")
    
    if not rn2483.init(SERIAL1, appeui, appkey, rst): # LoRa Click on slot A
        print("denied :(")
        raise Exception
 
    print("sending first message, res:")
    print(rn2483.tx_uncnf('TTN'))
 
    temp_hum = hts221.HTS221( I2C1,D31 ) # Temp Hum Click on slot C
    
    while True:
        temp, hum = temp_hum.get_temp_humidity()
        print('temp: ', temp, 'hum: ', hum)
        data = bytearray(4) 
        data[0:2] = bytearray([ int(temp) + 127, int((temp - int(temp)) * 100) ])
        data[2:4] = bytearray([ int(hum) + 127, int((hum - int(hum)) * 100) ])
        r = rn2483.tx_uncnf(data) # send data to TTN
        sleep(5000)
        
except Exception as e:
    print(e)

get_plot_data_TTN.py

Python
# Get and plot data from TTN Console using Python
 
import paho.mqtt.client as mqtt
import json
import base64
 
APPEUI = 'YOURAPPEUI'
APPID  = 'YOUAPPID'
PSW    = 'YOURPASSWORD'
 
import matplotlib.pyplot as plt
#import DataPlot and RealtimePlot from the file plot_data.py
from plot_data import DataPlot, RealtimePlot
 
fig, axes = plt.subplots()
plt.title('Data from TTN console')
 
data = DataPlot()
dataPlotting= RealtimePlot(axes)
 
count=0
 
def bytes_to_decimal(i,d):
    xx = i - 127
    dec = (-d if xx < 0 else d)/100
    return xx + dec
 
def on_connect(client, userdata, flags, rc):
    client.subscribe('+/devices/+/up'.format(APPEUI))
 
def on_message(client, userdata, msg):
    j_msg = json.loads(msg.payload.decode('utf-8'))
    dev_eui = j_msg['hardware_serial']
 
    tmp_hum = base64.b64decode(j_msg['payload_raw'])
    tmp = bytes_to_decimal(*tmp_hum[0:2])
    hum = bytes_to_decimal(*tmp_hum[2:4])
 
    # print data
    print('---')
    print('tmp:', tmp, ' hum:', hum)
    print('dev eui: ', dev_eui)
 
    # plot data
    global count
    count+=1
    data.add(count, tmp , hum)
    dataPlotting.plot(data)
    plt.pause(0.001)
 
# set paho.mqtt callback
ttn_client = mqtt.Client()
ttn_client.on_connect = on_connect
ttn_client.on_message = on_message
ttn_client.username_pw_set(APPID, PSW)
ttn_client.connect("eu.thethings.network", 1883, 60) #MQTT port over TLS
 
try:
    ttn_client.loop_forever()
except KeyboardInterrupt:
    print('disconnect')
    ttn_client.disconnect()

plot_data.py

Python
import time
import math
from collections import deque , defaultdict
 
import matplotlib.animation as animation
from matplotlib import pyplot as plt
 
import threading
 
from random import randint
 
from statistics import *
 
class DataPlot:
    def __init__(self, max_entries = 20):
        self.axis_x = deque(maxlen=max_entries)
        self.axis_y = deque(maxlen=max_entries)
        self.axis_y2 = deque(maxlen=max_entries)
 
        self.max_entries = max_entries
 
        self.buf1=deque(maxlen=5)
        self.buf2=deque(maxlen=5)
 
     
    def add(self, x, y,y2):
 
        self.axis_x.append(x)
        self.axis_y.append(y)
        self.axis_y2.append(y2)
 
class RealtimePlot:
    def __init__(self, axes):
     
        self.axes = axes
 
        self.lineplot, = axes.plot([], [], "ro-")
        self.lineplot2, = axes.plot([], [], "go-")
 
    def plot(self, dataPlot):
        self.lineplot.set_data(dataPlot.axis_x, dataPlot.axis_y)
        self.lineplot2.set_data(dataPlot.axis_x, dataPlot.axis_y2)
 
        self.axes.set_xlim(min(dataPlot.axis_x), max(dataPlot.axis_x))
        ymin = min([min(dataPlot.axis_y), min(dataPlot.axis_y2)])-10
        ymax = max([max(dataPlot.axis_y), max(dataPlot.axis_y2)])+10
        self.axes.set_ylim(ymin,ymax)
        self.axes.relim();
 
def main():
    fig, axes = plt.subplots()
    plt.title('Plotting Data')
 
    data = DataPlot();
    dataPlotting= RealtimePlot(axes)
 
    try:
        count=0
        while True:
            count+=1
            data.add(count, 30 + 1/randint(1,5) , 35 + randint(1,5))
            dataPlotting.plot(data)
 
            plt.pause(0.001)
    except KeyboardInterrupt:
        print('\n\nKeyboard exception received. Exiting.')
        plt.close()
        ser.close()
        exit()
 
if __name__ == "__main__": main()

Credits

Luigi Francesco Cerfeda

Luigi Francesco Cerfeda

2 projects • 56 followers
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