The PCF8574 is an 8 bits I/O port expander that uses the I2C protocol. Using this IC, you can use only the SDA and SCL pins of your Arduino board to control up to 8 digital I/O ports. A0,A1,A2 are address pins P0,P1,P2,P3,P4,P5,P6,P7 are digital…

The ADXL345 is a small, thin, low power, 3-axis accelerometer with high resolution (13-bit) measurement at up to ±16g. Digital output data is formatted as 16-bit twos complement and is accessible through either a SPI (3- or 4-wire) or I2C digital interface. The ADXL345 is…

This is a simple example using the Waveshare DVK512. You press a key and this is displayed on the command line, one of the 4 LEDs is also lit for each of the 4 buttons on the board You can see the LEDS (9) and Buttons…

Recently I bought a DVK512 Raspberry Pi Expansion Board from Waveshare for my raspberry Pi. If you have never heard of the DVK512 the its a reasonably priced add-on (hat). The following features and image are from the Waveshare site UART interface: easily connects to UART modules…

Handy if you lose the information Distribution | Username | Password —————|————|————- Debian Squeeze | pi | raspberry Arch | root | root QtonPi | root | rootme Raspbian | pi | raspberry OpenElec | root | openelec Pidora | root | raspberrypi RISC OS…

In this example we will connect one of the popular 8×8 LED matrix modules that can be found at low cost on various web sites. These commonly use a MAX7219 Here is how to connect this to your Raspberry Pi Board Pin Name RPi Pin…

In a previous example at connecting a mcp23017 to your raspberry pi we used a python script to flash LEDs connected to mcp23017 but there are other options available. In this example we look at a command line tool called i2cset i2cset is a small helper…

If you need to add more I/O lines to your Raspberry PI you can connect an mcp23017. The MCP23017 uses two i2c pins and this gives you 16 general purpose pins. You can set each of 16 pins to be input, output, or input with a…

One of the frustrating things about the Raspberry PI is the lack of any analogue inputs, this means there are a number of sensors that are commonly used that cannot be used quite so easily on a Raspberry PI. Examples of these are light dependent…

MCP9808 digital temperature sensor example The MCP9808 digital temperature sensor converts temperatures between -20°C and +100°C to a digital word with ±0.5°C (max.) accuracy. The MCP9808 comes with user-programmable registers that provide flexibility for temperature sensing applications. The registers allow user-selectable settings such as Shutdown…