Khalil set up a Raspberry Pi with a LAMP server and wired temperature/humidity sensor to acquire readings from his bedroom. He displayed the readings on a simple website hosted on the Pi and accessible remotely over the internet. The project stayed under budget at $100 and involved soldering the sensor, programming in C and Python, and setting up a MySQL database to log readings every 60 seconds for graphing temperature and humidity trends over 24 hours.

1. Khalil Abdul-Fattah IT499

2.  Set up Raspberry Pi with all necessary software
components for a LAMP server
 LAMP = Linux/Apache/MySQL/PHP, Perl
 Wired temperature/humidity sensor to Pi,
acquire and display readings from my bedroom
 Worked primarily via terminal and Emacs/Vim
text editors
 Got it fully up and running online so that it’s
accessible from outside of LAN
 Attempted to keep budget low ($100 max)

3.  Raspberry Pi Model B+ (2014 model)
 700MHz CPU (overclocked to 800MHz)
 512MB SDRAM
 Ports: HDMI, 4xUSB 2.0, Ethernet, Micro
USB power socket
 8GB pre-installed microSD card for storage
and Raspbian OS
 40-pin GPIO connector
 Extra peripherals including case and HDMI
cable
 Total package = ~$60
 AM2302 wired temperature-humidity
sensor
 3 to 5V power
 Reads humidity from 0 to 100% with 2 to
5% margin of error
 Reads temperature from -40 to 80 degrees
Celsius with +-0.5 degrees C margin of error
 Cost = $15

4.  PoEAdapter
 Provides power over Ethernet conversion
 Potentially allows for greater mobility (don’t need to
plug into power outlet)
 Electrical wiring woes
 Out $20…
 …But unintentionally worked as a barrier between Pi
and sensor to block electrical interference!
 Wi-Fi networking
 Would have allowed further mobility
 UnstableWi-Fi environment at home
 Raspberry Pi camera add-on
 To capture still images of Pi location, just for fun
 Wouldn’t fit properly with case
 Budget was climbing
 Considered building multiple units to
monitor/compare two or more locations at once
 Too time consuming and costly

5.  Had to solder sensor wires
to proper GPIO (General
Purpose Input/Output) pins
 Red to pin 1 (power)
 Yellow to pin 7 (data)
 Black to pin 9 (grounding)
 Maybe trickiest part of
project (wires are thin and
easy to burn through)
 GPIO pins not enabled by
default
 Must be turned on by
modifying code in wiringPi C
program

6.  Apache PiWeb server initially
LAN only; single mostly blank
Web page
 Created MySQL database,
“Monitor”
 Table “TempHumid”
▪ Columns: ComputerTime (Unix
Epoch: seconds since 1970)
▪ Temperature (degrees Celsius)
▪ Humidity (percentage)
 Query: Select * fromTempHumid
 Later added statement to
convert Celsius to Fahrenheit
 Many issues trying to enter
MySQL commands into
terminal

7.  TH.c:
 C program to take
readings from sensor and
insert into database
 Includes/calls wiringPi
library
 Waits 60 seconds
 Loops so it keeps going
until Pi powers down
 TH.log:
 System log file that makes
sureTH.c starts every time
Raspberry Pi is booted up

8.  Matplotlib:
 open-source, powerful, versatile
math plotting program
 Utilizes python scripts
 GraphTH.py:
 Includes/calls matplotlib library
 Graphs last 24 hours of readings
from MySQL database using
simple x/y coordinates
 CreatesTH.png image and puts
it in server directory /var/www
every 60 seconds
 Issue: supposed to ignore
anomalies, but graphs them
anyway

9.  Simple Website consists of three
pages:
▪ Home with about section and description,
navigation column and links
▪ Table page that uses PHP to display data
from MySQL database on Pi; converts
ComputerTime to standard date & time
format
▪ Graph page where updated graph PNG
image is uploaded every 60 seconds
 Registered free domain name at
dnsdynamic.org:
▪ Home: http://khalil.wow64.net/index.html
▪ Table: http://khalil.wow64.net/test.php
▪ Graph: http://khalil.wow64.net/graph.html
 DNS is unreliable, goes down
frequently
▪ Use IP address:
http://108.185.174.217/index.html