I decided to pick this project up again after it got interrupted by my move to San Francisco. I have a couple weeks between jobs and thought I could get this working in that time frame.
The goal is to make a solar powered Raspberry Pi weather station with accompanying website (available here). The weather station would take a picture of the view from the roof of my apartment building every 10 seconds, posting that picture on the website. Additionally a temperature and humidity sensor would take data and store it on google spreadsheets at the same rate. A graph of this would be visible on the website. At night the Pi would take all the pictures and make a timelapse video of the day, upload that to youtube and that video would display on the front page of the website.
A lot to promise!
Today's post is a bit dry as it is entirely code, but if you are interested in doing something similar yourself, it will be useful.
As of today, I have code that can...
- take data from the temperature and humidity sensor (Available Here)
- write data to google spreadsheets
- take a picture with the picamera
- store that picture on dropbox
I am working on writing code to...
- take a set of jpeg images and create a .mov (hopefully using ffmpeg)
- upload that .mov to youtube
- managing the images (will delete each day's pictures from local storage)
- schedule everything using crontab
I will get to writing the code for...
- the entire website
- managing dropbox's images (I would run out of space in about 10 days without managing storage).
So I'll start by documenting what I have done.
Interfacing With The DHT22 Sensor
This took a lot of trial and error. I ended up finding this
tutorial and, while the website looks ridiculous, it worked like a charm!
Bash commands / packages to install:
sudo apt-get install git
cd ~
git clone https://github.com/adafruit/Adafruit_Python_DHT.git
cd Adafruit_Python_DHT
sudo apt-get update
sudo apt-get install build-essential python-dev
sudo python setup.py install
Python code:
import Adafruit_DHT as dht
import datetime
h,t = dht.read_retry(dht.DHT22, 4)
Writing Data To Google Sheets
First, create a spreasheet where your data will sit. Delete all but one row (there are only 1000 rows so if you delete rows 2-1000 you will be left with only the first row).
Next is a bit tricky because while Google updates its APIs regularly it doesn't, apparently, always keep its documentation up to date. I followed google's own documentation (found
here), but ran into problems. Two hours later, I found the solution
here.
So, if you are doing this yourself, follow the google tutorial, just replace the python in step 6 with what I have below (with certain things replaced to refer to your own project, of course).
Bash commands / packages to install:
pip install PyOpenSSL
pip install --upgrade oauth2client
Python code:
import json
import gspread
from oauth2client.service_account
import ServiceAccountCredentials
#The following refers to the json file created by google. It must be placed in the same directory as this script.
json_key = 'WeatherStation-41a4ca0f181e.json' #replace with your own
scope = ['https://spreadsheets.google.com/feeds']
#this service account credentials part was what was not documented.
credentials = ServiceAccountCredentials.from_json_keyfile_name(json_key, scope)
gc = gspread.authorize(credentials)
sht = gc.open('WeatherStationData') #the name of the spreadsheet
wrksht = sht.worksheet('Sheet1') #the name of the worksheet
wrksht.append_row([datetime.datetime.now(), t, h]) #append the data
Picamera
This is well documented and easy to use. All information can be found
here.
I chose to use the date and time as the file name for a couple of reasons. One is that the pictures have a lot to do with time, so if I ever need to find one taken at a particular time, I search by file name. The other reason is that the date and time is always unique so I know I won't have any file naming errors.
However, if you do use datetime.datetime.now() you have to do two things:
- Change the date and time of your pi to local time from Universal Time (for your convenience and sanity)
- Replace all strange characters like ':' with '_' so you make sure you know the naming format
I did a little more with naming and replaced all non-numeric characters with '_' and removed the sub-second digits as they were not necessary for this project.
Bash commands / packages to install:
Enable picamera
sudo raspi-config
Change date and time
sudo dpkg-reconfigure tzdata
Install picam library
sudo apt-get update
sudo apt-get install python-picamera
Note: This is for python 2.7. If you want to use python 3, read the
tutorial.
Python code:
import picamera
import datetime
#define filename as year_month_day_hour_minute_second.jpg
temp = str(datetime.datetime.now())
print temp
file_name = ''
for char in temp:
if char == ":" or char == "-" or char == " ": #want to replace all with '_'
file_name += "_"
elif char == ".": #exclude fractional seconds
break
else:
file_name += char
file_name += ".jpg"
#take picture
camera = picamera.PiCamera()
camera.capture(file_name)
Storing Picture on Dropbox
This takes a little extra than just the dropbox api.
This tutorial walks you through the entire procedure in painful detail. So painful, in fact, that I won't rehash it here.
Bash commands / packages to install:
Read the tutorial!
Python code:
from subprocess import call
photofile = "/home/pi/Documents/weatherprojects/Dropbox-Uploader/dropbox_uploader.sh upload /home/pi/Documents/weatherprojects/{} {}".format(file_name, file_name)
call ([photofile], shell=True)
That's all for now!
