To keep costs low, the Raspberry Pi does not include a Real Time Clock module. Instead, users are expected to have it always connected to WiFi or Ethernet and keep time by checking the network. Since we want to include an external module, we'll have to wire one up. We'll go with the easy-to-use and low-cost DS1307.
In this tutorial we'll be showing how to utilize a DHT sensor Python library based on C for high-speed GPIO polling to handle bit-banged sensor output. Many low cost sensors have unusual output formats, and in this case, a "Manchester-esque" output that is not SPI, I2C or 1-Wire compatible must be polled continuously by the Pi to decode. Luckily, the C GPIO libraries are fast enough to decode the output.
Adding a LCD to any project immediately kicks it up a notch. This tutorial explains how to connect a inexpensive HDD44780 compatible LCD to the raspberry pi using 6 GPIOs. While there are other ways to connect using I2C or the UART this is the most direct method that get right down the bare metal. This technique allows for less expensive LCDs to be used, it does not require any i2c drivers and it won't steal the only serial port on the Pi.
Teaching the raspberry pi how to read analog inputs is easier than you think. The Pi does not include a hardware analog to digital converter, but a external chip can be used along with some bit banged SPI code in python to control read external analog devies such as (but not limited to): - potentiometer - photocell - force sensitive resistor ( fsr ) - temperature sensor
Once soldered together, the cable plugs between the Pi computer and the Cobbler breakout. The Cobbler can plug into any solderless breadboard (or even a prototyping board like the PermaProto). The Cobbler PCB has all the pins labeled nicely so you can go forth and build circuits without keeping a pin-out printout at your desk. We think this will make it more fun to expand the Pi and build custom circuitry with it.
Now that you've finally got your hands on a Raspberry Pi® , you're probably itching to make some fun embedded computer projects with it. What you need is an add on prototyping Pi Plate from Adafruit, which can snap onto the Pi PCB (and is removable later if you wish) and gives you all sorts of prototyping goodness to make building on top of the Pi super easy.
Raspberry Pi’s popularity makes things so easy that it is almost scary. I set forth on a simple starter project of having the Pi show me when new GMail messages arrive. After some searching it seems that lots of people are already talking about how to do this and there are some great examples. Michael over at MitchTech had the most ready to go code which I pilfered from. Adafruit's Cobbler Breakout Kit makes the bread board experience even easier with the clearly labeled pins for each of raspi’s GPIOs.
One of the great things about the Raspberry Pi is how everyone starts with same piece of gear. Since the sound cards are identical on every unit it is trivial to load the drivers and play mp3 files. This guide describes how to connect input buttons and play audio files using a Raspberry Pi with Python. We make use of the Adafruit's Pi Cobbler Breakout Kit and the python module RPi.GPIO. If you have not already used the raspberry pi as a input device this guide will show you how to wire the pull-down resistors to the GPIO pins and buttons.
The combination of connecting a Raspberry Pi to COSM makes creating a internet of things much easier than it has been in the passed. The Pi with it's easy access to ethernet and COSM's drop dead simple usability will graph all sensor data you send to it. This tutorial explains how to connect a analog temperature sensor to the Pi and use a small python script to upload that data for storage and graphing on COSM.