ADC Pi - Raspberry Pi Analogue to Digital Converter

£21.59 each

Ex VAT: £17.99

63 in stock


Product Code: ADCPIV2


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The ADC Pi V2.2 is an 8 channel 17 bit analogue to digital converter designed to work with the Raspberry Pi platform.  The ADC Pi is based on two Microchip MCP3424 A/D converters each containing 4 analogue inputs with up to 18 bit resolution.  The MCP3424 is a delta-sigma A/D converter with low noise differential inputs. We designed the ADC Pi to work as a single ended A/D converter using the internal 2.048V reference voltage with the -V pins tied to ground.     A voltage divider on the ADC Pi board brings the input voltage range to a much more useful 0 – 5.06V. In this configuration the sample size is 17 bits for each channel.

The ADC Pi is powered through the host Raspberry Pi using the GPIO port and extended pins on the GPIO connector allow you to stack the ADC Pi along with other expansion boards.

The two MCP3424 A/D converters communicate via i2c to the host Raspberry Pi giving you eight analogue inputs to use.  A logic level converter is included on the ADC Pi board giving you a buffered 5V i2c port making it easy to add other I2C devices which operate at 5 volts without damaging the raspberry pi 3.3 volt i2c port.  The i2c buffer uses N-channel mosfets with a maximum drain current of 100mA.

Datasheets for the MCP3424 can be found on the technical information tab.

The I2C address bits are selectable using the on-board jumpers.  The MCP3424 supports up to 8 different I2C addresses so with two A/D converters on each ADC Pi you can stack up to 4 ADC Pi boards on a single Raspberry Pi giving you 32 ADC inputs.

The MCP3424 contains an on-board 2.048V reference voltage with an input range of ±2.048V differentially (full scale range of 4.096V/PGA).  A programmable Gain Amplifier gives the user a selectable gain of x1, x2, x4 or x8 before the analogue to digital conversion takes place.

The data rate for analogue to digital conversions is 3.75 (17 bit), 15 (15 bit), 60 (13 bit) or 240 (11 bit) samples per second. Data rate and resolution can be configured within software using the I2C interface.

Unused inputs should be tied to ground.

Additional Information:

Datasheets

ADC Pi V2.1 Address Configuration and Specification (Current Model)

ADC Pi V2 Address Configuration and Specification (Previous Model)

MCP3424

Input Ratings & Specifications

Maximum voltage on ADC inputs: ± 5.0V

Maximum current on i2c port: 100mA.

Schematic

Click to download
Click to download schematic PDF.

Sample Code

The Quick2wire lib from https://github.com/quick2wire/quick2wire-python-api allows easy access to the I2C port via Python.

Download demo code for the ADC Pi V2 and ADC Pi V2.1.

 

Difficult to use and very slow by Simon Howroyd submitted on 20/03/2014

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This looks great built well etc etc.To use the configuration register is far too complicated for what is needed. There is a continuous conversion mode but this is only of use if you are only reading the same channel. As soon as you change channel you have to sit and wait for it to perform the reading and conversion. I am running all 8 channels and this takes forever for me about 1Hz in the 15SPS 16bit mode.In a nutshell if you want to constantly read 1 or 2 channels then it is ok make sure you use one channel from each chip eg one from 0-3 and the other 4-7. If you are using all 8 then prepare to wait. ------- From AB Electronics, the details tab does specify the sample rate at: The data rate for analogue to digital conversions is 3.75 (17 bit), 15 (15 bit), 60 (13 bit) or 240 (11 bit) samples per second


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The following tutorials are available for the ADC Pi analogue to digital converter board.

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