Reference Guide

I2C Pin Out (from DFRobot Gravity)


The DFRobot Gravity Series stands as a premium open-source electronics toolkit, designed to be modular, plug-and-play, and accessible to all. Featuring robust expansion shields, a diverse array of professional-grade functional modules boasting standard interfaces, and comprehensive documentation, the Gravity Series empowers users of any expertise level to effortlessly connect and combine components, bringing their ideas to life or advancing their projects with ease.

I2C connector pinout for DFRobot Gravity

The I2C cable used for Gravity (DFRobot) is the same connector used for Grove (Seeed Studio) and Stemma (Adafruit), but however the pin out wiring is not the same. So while you can use the I2C cable, but you cannot mixed and inter-connect Gravity electronic board with the other brands. An adaptor cable is needed to do the signal line conversion.

Gravity I2C connector details

Gravity I2C inter-connection system uses PH series from JST. JST specialises in connector product. The following is the datasheet and drawing for the JST PH series connectors use.

Cable Plug

Housing part number: PHR-4
– Available from Digikey: 455-1164-ND

Crimp Pin part number: SPH-002T
– Available from Digikey: 455-1127

Board Socket

– Socket part number: B4B-PH-K-S (Available from Digikey: 455-1706-ND)
– Socket part number: S4B-PH-K-S (Available from Digikey: 455-1721-ND)

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I2C Pin Out (STEMMA QT from Adafruit)

STEMMA QT is a connector system designed to simplify connecting sensors and other devices to microcontrollers and single-board computers. Used by Adafruit, STEMMA QT aims to streamline the process of prototyping and building electronics projects.

Do note that STEMMA AT, and STEMMA are both the same I2C connection standard, however they are different in size. STEMMA AT is smaller in size (1mm pitch), while STEMMA is easier to handle (2mm pitch).

I2C pinout for STEMMA QT from Adafruit

STEMMA QT connectors typically feature a standardized pinout, making it easy to plug and play with compatible devices. With STEMMA QT, you can quickly connect sensors, displays, actuators, and other peripherals without worrying about wiring configurations or compatibility issues.

One of the key advantages of STEMMA QT is its versatility. It’s compatible with a wide range of microcontrollers and single-board computers, including popular platforms like Arduino, Raspberry Pi, and Adafruit’s own CircuitPython boards. This compatibility makes it a convenient choice for makers and hobbyists working on diverse projects.

Overall, STEMMA QT provides a user-friendly interface for integrating sensors and devices into your electronics projects, allowing you to focus on experimentation and creativity rather than wrestling with wires and connectors. Whether you’re a beginner or an experienced maker, STEMMA QT can help streamline your prototyping process and bring your ideas to life.

The I2C cable connector from STEMMA QT (Adafruit) is compatible to qwIIC (Sparkfun Electronics). Their connector and the pin out are the same.

STEMMA QT I2C connector details

STEMMA QT I2C inter-connection system uses SH/SR series from JST. JST specialises in connector product. The following is the datasheet and drawing for the JST SH SR series connectors use.

Cable Plug

Housing part number: SHR-04V-S-B
– Available from Digikey: 455-1379-ND

Crimp Pin part number: SSH-003T
– Available from Digikey: 455-1561-2-ND

Board Socket

– Socket part number: BM04B-SRSS-TB (Available from Digikey: 455-BM04B-SRSS-TB)
– Socket part number: SM04B-SRSS-TB (Available from Digikey: 455-SM04B-SRSS-TB)

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