ModularSensors > Modules > Supported Sensors > Atlas Scientific EZO Circuits

Atlas Scientific EZO Circuits module

The Sensor and Variable objects for all Atlas EZO circuits.

This library currently supports the following Atlas Scientific sensors:

The chips have operating voltages between 3.3V and 5V; power can be stopped between measurements. The probes and sensors can (and should) be calibrated using sketches provided by Atlas Scientific on their website. Atlas Scientific recommends that you integrate their sensor chips into a board, so you can buy one from them or make your own (example:

The code in ModularSensors requires the Atlas Sensors to communicate over I2C. Atlas scientific sensors are shipped with probes and sensor chips that communicate using UART by default. Data sheets, found on the Atlas Scientific website, show how to manually switch the chips to I2C. Before deploying your Atlas chip chip and sensor, I recommend locking the protocol (plock) to I2C so the sensors do not accidentally switch back to UART mode. Legacy chips and EZO chips that do not support I2C are not supported.

Build flags

Both hardware and software I2C communication is supported for the Atlas sensors. Use the build flag -D MS_ATLAS_SOFTWAREWIRE to switch to software I2C. Only Testato's SoftwareWire is currently supported.

    • switches from using hardware I2C to software I2C


module Atlas EZO-CO2
module Atlas EZO-DO
module Atlas EZO-EC
module Atlas EZO-ORP
module Atlas EZO-pH
module Atlas EZO-RTD


class AtlasParent
A parent class for Atlas EZO circuits and sensors.