mscroggs.co.uk
mscroggs.co.uk

subscribe

Blog

Raspberry Pi weather station

 2013-07-11 
On 19 June, the USB temperature sensor I ordered from Amazon arrived. This sensor is now hooked up to my Raspberry Pi, which is taking the temperature every 10 minutes, drawing graphs, then uploading them here. Here is a brief outline of how I set this up:

Reading the temperature

I found this code and adapted it to write the date, time and temperature to a text file. I then set cron to run this every 10 minutes. It writes the data to a text file (/var/www/temperature2) in this format:
2013 06 20 03 50,16.445019
2013 06 20 04 00,16.187843
2013 06 20 04 10,16.187843
2013 06 20 04 20,16.187843

Plotting the graphs

I found a guide somewhere on the internet about how to draw graphs with Python using Pylab/Matplotlib. If you have any idea where this could be, comment below and I'll put a link here.
In the end my code looked like this:
 python 
import time
import matplotlib as mpl
mpl.use("Agg")
import matplotlib.pylab as plt
import matplotlib.dates as mdates

ts = time.time()
import datetime
now = datetime.datetime.fromtimestamp(ts)
st = mdates.date2num(datetime.datetime(int(float(now.strftime("%Y"))),
                                       int(float(now.strftime("%m"))),
                                       int(float(now.strftime("%d"))),
                                       0, 0, 0))
weekst = st - int(float(datetime.datetime.fromtimestamp(ts).strftime("%w")))
= file("/var/www/temperature2","r")
= []
= []
tt = []
ss = []
= []
= []
= []
= []
= []
weekt = []
weektt = []
weeks = []
weekss = []
mini = 1000
maxi = 0
cur = -1
datC = 0

for line in f:
    fL = line.split(",")
    fL[0] = fL[0].split(" ")
    if cur == -1:
        cur = mdates.date2num(datetime.datetime(int(float(fL[0][0])),
                                                int(float(fL[0][1])),
                                                int(float(fL[0][2])),
                                                0,0,0))
        datC = mdates.date2num(datetime.datetime(int(float(fL[0][0])),
                                                 int(float(fL[0][1])),
                                                 int(float(fL[0][2])),
                                                 int(float(fL[0][3])),
                                                 int(float(fL[0][4])),
                                                 0))
    u.append(datC)
    v.append(fL[1])
    if datC >= st and datC <= st + 1:
        t.append(datC)
        s.append(fL[1])
    if datC >= st - 1 and datC <= st:
        tt.append(datC + 1)
        ss.append(fL[1])
    if datC >= weekst and datC <= weekst + 7:
        weekt.append(datC)
        weeks.append(fL[1])
    if datC >= weekst - 7 and datC <= weekst:
        weektt.append(datC + 7)
        weekss.append(fL[1])
    if datC > cur + 1:
        g.append(cur)
        h.append(mini)
        i.append(maxi)
        mini = 1000
        maxi = 0
        cur = mdates.date2num(datetime.datetime(int(float(fL[0][0])),
                                                int(float(fL[0][1])),
                                                int(float(fL[0][2])),
                                                0,0,0))
    mini = min(float(fL[1]),mini)
    maxi = max(float(fL[1]),maxi)
g.append(cur)
h.append(mini)
i.append(maxi)

plt.plot_date(x=t,y=s,fmt="r-")
plt.plot_date(x=tt,y=ss,fmt="g-")
plt.xlabel("Time")
plt.ylabel("Temperature (#^\circ#C)")
plt.title("Daily")
plt.legend(["today","yesterday"], loc="upper left",prop={"size":8})
plt.grid(True)
plt.gca().xaxis.set_major_formatter(mdates.DateFormatter("%H:%M"))
plt.gcf().subplots_adjust(bottom=0.15,right=0.99)
labels = plt.gca().get_xticklabels()
plt.setp(labels,rotation=90,fontsize=10)
plt.xlim(st,st + 1)
plt.savefig("/var/www/tempr/tg1p.png")

plt.clf()

plt.plot_date(x=weekt,y=weeks,fmt="r-")
plt.plot_date(x=weektt,y=weekss,fmt="g-")
plt.xlabel("Day")
plt.ylabel("Temperature (#^\circ#C)")
plt.title("Weekly")
plt.legend(["this week","last week"], loc="upper left",prop={"size":8})
plt.grid(True)
plt.gca().xaxis.set_major_formatter(mdates.DateFormatter("                     %A"))
plt.gcf().subplots_adjust(bottom=0.15,right=0.99)
labels = plt.gca().get_xticklabels()
plt.setp(labels,rotation=0,fontsize=10)
plt.xlim(weekst,weekst + 7)
plt.savefig("/var/www/tempr/tg2p.png")

plt.clf()

plt.plot_date(x=u,y=v,fmt="r-")
plt.xlabel("Date & Time")
plt.ylabel("Temperature (#^\circ#C)")
plt.title("Forever")
plt.grid(True)
plt.gca().xaxis.set_major_formatter(mdates.DateFormatter("%d/%m/%y %H:%M"))
plt.gcf().subplots_adjust(bottom=0.25,right=0.99)
labels = plt.gca().get_xticklabels()
plt.setp(labels,rotation=90,fontsize=8)
plt.savefig("/var/www/tempr/tg4p.png")


plt.clf()

plt.plot_date(x=g,y=h,fmt="b-")
plt.plot_date(x=g,y=i,fmt="r-")
plt.xlabel("Date")
plt.ylabel("Temperature (#^\circ#C)")
plt.title("Forever")
plt.legend(["minimum","maximum"], loc="upper left",prop={"size":8})
plt.grid(True)
plt.gca().xaxis.set_major_formatter(mdates.DateFormatter("%d %b"))
plt.gcf().subplots_adjust(bottom=0.15,right=0.99)
labels = plt.gca().get_xticklabels()
plt.setp(labels,rotation=90,fontsize=8)
plt.savefig("/var/www/tempr/tg3p.png")
If there's anything in there you don't understand, comment below and I'll try to fill in the gaps.

Uploading the graphs

Finally, I upload the graphs to mscroggs.co.uk/weather. To do this, I set up pre-shared keys on the Raspberry Pi and this server and added the following as a cron job:
 bash 
0 * * * * scp /var/www/tempr/tg*p.png username@mscroggs.co.uk:/path/to/folder
I hope this was vaguely interesting/useful. I'll try to add more details and updates over time. If you are building something similar, please let me know in the comments; I'd love to see what everyone else is up to.
Edit: Updated to reflect graphs now appearing on mscroggs.co.uk not catsindrag.co.uk.

Similar posts

How OEISbot works
Logic bot
Logical contradictions
Logic bot, pt. 2

Comments

Comments in green were written by me. Comments in blue were not written by me.
 Add a Comment 


I will only use your email address to reply to your comment (if a reply is needed).

Allowed HTML tags: <br> <a> <small> <b> <i> <s> <sup> <sub> <u> <spoiler> <ul> <ol> <li>
To prove you are not a spam bot, please type "number" in the box below (case sensitive):

Archive

Show me a random blog post
 2020 

Feb 2020

PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2

Jan 2020

PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
 2019 
▼ show ▼
 2018 
▼ show ▼
 2017 
▼ show ▼
 2016 
▼ show ▼
 2015 
▼ show ▼
 2014 
▼ show ▼
 2013 
▼ show ▼
 2012 
▼ show ▼

Tags

realhats arithmetic people maths national lottery football big internet math-off puzzles rhombicuboctahedron london underground go menace cross stitch christmas card speed pizza cutting news bempp royal institution video games mathslogicbot polynomials folding tube maps interpolation geometry chebyshev oeis machine learning sorting graph theory asteroids stickers curvature map projections ternary boundary element methods flexagons games bodmas chalkdust magazine mathsteroids phd matrix of minors sobolev spaces misleading statistics reddit signorini conditions fractals folding paper european cup talking maths in public logic computational complexity mathsjam radio 4 ucl accuracy determinants game show probability preconditioning christmas electromagnetic field advent calendar hexapawn data visualisation world cup draughts matrix multiplication noughts and crosses sport pythagoras tennis javascript estimation gaussian elimination error bars hats inline code golden ratio cambridge trigonometry twitter finite element method rugby triangles sound harriss spiral inverse matrices palindromes final fantasy chess captain scarlet reuleaux polygons martin gardner manchester science festival royal baby dates probability wool propositional calculus tmip programming frobel simultaneous equations hannah fry platonic solids london wave scattering golden spiral game of life weak imposition manchester plastic ratio gerry anderson a gamut of games binary craft php books approximation bubble bobble dataset matrices python numerical analysis data latex matt parker dragon curves braiding countdown weather station raspberry pi coins light nine men's morris pac-man statistics the aperiodical matrix of cofactors

Archive

Show me a random blog post
▼ show ▼
© Matthew Scroggs 2012–2020