Breakout board based on the integrated analog / digital converter MCP3221 (SMD type SOT-23-5) of Microchip. The integrated allows the A / D conversion with a resolution of 12 bits (4096 steps) as a function of the supply voltage. If the device is powered at 5 V, the extension of the dynamic range at the input is 5000 mV then the translation, intended as a voltage value corresponding to the smallest portion sampled (one bit of the 4096 possible) is obtained by the ratio 5.000 / 4.096, or Vdd / 4,096. The maximum input voltage for the conversion, is also a function of the supply voltage. Specifically, the voltage on pin AIN may be at most that of the supply voltage. The A / D converter has an output type I²C-Bus running clocked at 100 kHz in the I²C Standard Mode and up to 400 kHz in fast mode. The sampling at a maximum rate of 22.3 ksps in I²C Fast Mode. The breakout board is interfaced with Arduino without the aid of any specific library, as it uses the Wire library already available basic IDE. The integrated used can be programmed with its own address between 8 available, so you can use up to 8 boards connected to the same communication lines SDA and SCL. Power connections, which digitize the analog input signal and the I²C bus are made available through the connectors on the side of the card; the same is repeated on a row of pitches to 2.54 mm prepared to mount a pin-strip that allows the quick breakout board on the electronic board where you want to add the ADC.

Sketch Arduino