STEMMA QT / Qwiic / e-Radionica EasyC / Modulino Comparison

Qwiic is SparkFun's I2C prototyping system. It's only for use with I2C devices. There's also only one cable, a JST SH 4-pin connector and will only use it for I2C. Qwiic is a bit newer than Grove, it was created around May 2017.

Compatibility:

• Like Qwiic, STEMMA QT only uses the 4-pin connectors for I2C. The STEMMA QT connector is identical to the Qwiic connector and uses the same pin ordering.

Differences:

• Qwiic only has level shifting and voltage regulation on the controller, not devices. So, you can use STEMMA + STEMMA QT devices with any Qwiic controller and you can use Qwiic devices on a STEMMA controller if you set the voltage jumper from 5V to 3V (and have a cable that converts the 2mm to 1mm pitch connector).

Arduino Modulino

Modulino is a system of I2C modules which were introduced in 2024. Originally as a kit and in May 2025 they became available individually. 

Modulino modules use a STM32C011F4 microcontroller with a 2.0 to 3.6v supply range using 3.3V signaling (not 5V compatible). Reference.

They have the same voltage (3.3V) and JST connection as Qwiic so you can treat it the same as Qwiic.

e-Radionica EasyC

This company also makes sensors and breakouts with the Qwiic connector, it is the same voltage as Qwiic so you can treat it the same