New Product – 4 Chan/16 Bit ADC for Raspberry Pi

SwitchDoc Labs is pleased to announce the immediate availability of the Grove (and Pin headers) 4Chan/16 Bit ADC for the Raspberry Pi (based on the industry standard ADS1115).  3.3V and 5V compatible.  Works with Raspberry Pi and with Arduino.

No question about it.   The lack of an Analog to Digital Converter is a pain on the Raspberry Pi.   We want to read those real world signals all the time and we didn’t have a good way of doing it.   And not one really workable ADC for the Grove either.   So, we designed the board above.   4 channels of 16 bit Analog to Digital nirvana.   Based on the TI ADS1115 IC.  Works on the Raspberry Pi and the Arduino.

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Compatibility

 

What are Grove Devices?

There are hundreds of Grove compatible devices out now from numerous manufacturers. Seeedstudio is one example. They have over 100 sensors and boards available.

Here is our Grove Tutorial.

SwitchDoc Labs has over 25 Grove products available and more coming soon.

Downloads

• – Current Specification for Grove4Ch16BitADC Board
• – Raspberry Pi Pure Python Software is at:  https://github.com/switchdoclabs/SDL_Pi_Grove4Ch16BitADC
• – Arduino and ESP8266 Software is at:  https://github.com/switchdoclabs/SDL_Arduino_Grove4Ch16BitADC

Three Ways to Connect

There are three different ways of connecting to this ADC board.

Using Pi2Grover on the Raspberry Pi and a Grove Cable

If you have a Pi2Grover board for the Raspberry Pi, connecting to the 4Chan/16BIt ADC board is simple.   Grove to Grove Cables will do this job.

 

Using a Female Jumper Converter Cable to Grove

If you want to use the GPIO pin headers directly on the Raspberry Pi, then you can use a Female Jumper to Grove Converter cable.

Using Female Header Jumper Cables

Finally, you can use traditional jumper cables to connect from the GPIO on the Raspberry Pi to the ADC board using the provide pin headers (already soldered!)

Features

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[list_item size=”small” icon=”icon-beaker” hex_color=””]The Missing Board for the Raspberry Pi[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Power and I2C Activity LEDs[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]4 Channels with Grove Analog Connectors[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Works with all Raspberry Pi boards, ESP8266 designs and Arduino Boards.[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Grove I2C connector provided[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Software Provided for Raspberry Pi, Arduino and ESP8266[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Pass Through Raspberry Pi GPIO Connector[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]All Grove Connectors support 5V[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Pin Headers provided for non Grove usage[/list_item]

[list_item size=”small” icon=”icon-beaker” hex_color=””]Supports both 3.3V and 5V I2C[/list_item]

[/list]

Theory of Operation

The ADS1115 is a very small, low-power, 16-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC). The ADS111/5 are extremely easy to configure and design into a wide variety of applications, and allow precise measurements to be obtained with very little effort. Both experienced and novice users of data converters find designing with the ADS1115 to be intuitive and problem-free.

The ADS111/5 consists of a ΔΣ analog-to-digital (A/D) core with adjustable gain, an internal voltage reference, a clock oscillator, and an I2C interface. An additional feature available on the ADS1115 is a programmable digital comparator that provides an alert on a dedicated pin. All of these features are intended to reduce required external circuitry and improve performance.  The ADS1115 functional block diagram is shown above.

The ADS1115 A/D core measures a differential signal, VIN, that is the difference of AINP and AINN. A MUX is available on the ADS1115. This architecture results in a very strong attenuation in any common-mode signals. The converter core consists of a differential, switched-capacitor ΔΣ modulator followed by a digital filter. Input signals are compared to the internal voltage reference. The digital filter receives a high-speed bitstream from the modulator and outputs a code proportional to the input voltage.

The ADS1115 has two available conversion modes: single-shot mode and continuous conversion mode. In single-shot mode, the ADC performs one conversion of the input signal upon request and stores the value to an internal result register. The device then enters a low-power shutdown mode. This mode is intended to provide significant power savings in systems that only require periodic conversions or when there are long idle periods between conversions. In continuous conversion mode, the ADC automatically begins a conversion of the input signal as soon as the previous conversion is completed. The rate of continuous conversion is equal to the programmed data rate. Data can be read at any time and always reflect the most recent completed conversion.

PinOut