Temperature Lab

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ABOUT

This is a Raspberry Pi-powered node.js application that reports the temperatures from DS18B20 temperature sensors.

PROJECT STATUS

Somewhat operational: thermometer readings are displayed on a webserver. Thermometers are able to be hot-swapped while the server is running. Data is logged to a SQLite3 databse.

INSTALLATION

Prerequisite: a Raspberry Pi with installed OS. We recommend the Raspberry Pi Educational Linux Distro from Adafruit: Occidentalis v0.2. It has built-in support for One Wire. One or more DS18B20 sensors is probably a good thing to have for this but not required to get things up and running.

Installing node.js:

Step 1: Download the latest stable version of node.js

~ $ wget http://nodejs.org/dist/v0.8.18/node-v0.8.18-linux-arm-pi.tar.gz

Step 2: Unzip and remove superfluous files

~ $ cd /usr/local
/usr/local $ sudo tar xzvf ~/node-v0.8.18-linux-arm-pi.tar.gz --strip=1
/usr/local $ sudo rm LICENSE
/usr/local $ sudo rm README.md
/usr/local $ sudo rm ChangeLog

Cloning the repository and installing modules

/usr/local $ cd ~
~ $ git clone https://github.com/flamescape/TemperatureLab.git
~ $ cd TemperatureLab
~ $ npm install socket.io
~ $ npm install express
~ $ npm install sqlite3

USAGE

Loading the kernel modules

In order to read the raw data from the DS18B20 sensors, we need to load the One Wire kernel modules. To do that, execute the following commands:

~ $ sudo modprobe w1-gpio
~ $ sudo modprobe w1-therm

To check that the modules loaded properly and that your sensor is functional, execute the following command:

cat /sys/bus/w1/devices/28-*/w1_slave

These modules must be loaded every time the RPi is booted for the temperature sensors to be read. To make things a little easier, you can load the modules at boot by editing /etc/modules and appending the following lines:

w1-gpio
w1-therm

Running the server

~ $ node server.js

Direct your web browser to http://localhost:8080 on the RPi (or to the RPi's local IP address from a different machine on the network) to view the lab.

LICENSE

TemperatureLab is released under the Simplified BSD License.