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Configure I²C Sensor Readings

The I²C interface is commonly used for connecting sensors to data-logging devices like the Hawks. I²C Sensors use 3 lines

  • Power (typically 3V3, but sometimes 5V)
  • SDA (Serial Data Line) - data is transmitted over this line
  • SCL (Serial Clock) - Clock signal

I²C is a multi-controller/multi-target interface - meaning multiple sensors can be connected to the same bus (i.e. you can wire in multiple I²C sensors into the same terminals on the Hawk.
Multiple sensors are managed as each sensor can be given a unique address (the Hawk uses 8-bit addresses).  The Hawk will specify which sensor it is aiming to read from. 

This means if you want to use multiple of a specific sensor, it will work provided you can give them different addresses.
Some sensors are only sold pre-configured with a single specific address meaning only one will be able to be used.

Wiring

The Ag-Tech1 card pin out is given here: Hawk Baseboard + Plug in Cards - Wiring+Pin Out

Key connections for an I²C sensor are:


FunctionHawk IO
I²C SDA4Connect to sensor SDA
3.3V output5Connect to sensor 3V3
I²C SCL6Connect to sensor SCL


Configuration

Configure Task

We must configure a task and set I²C Action 1 and/or I²C Action 2 as one of the task actions.

This means currently we can configure readings from 2 sensors. If you require more readings, speak to our support team. 

Above - Do I²C Action 1 hourly (sample sensor and log) - and upload the readings every 4 hours. 

Configure I²C Action

Sensor Type
Chose your sensor type from the dropdown
Specific sensors need to be integrated. Contact our support team to discuss options if you have a sensor not listed you wish to use
I²C Address
Typically leave as 0 to use the default address for the sensor integration
If you have multiple sensors with multiple addresses you would set the sensor address to read from here
Analogue Offset
Set the Hawk Analogue Input to log the sensor reading to
The offset is where the first reading will be stored (some sensors return multiple readings)
It is important to be aware of sensors which return multiple values to avoid clashes. Generally, it is best to use analogues 10+ to avoid any clashes
Sensor Parameter 1-3
Some specific sensors have additional parameters which these fields are used for. For the majority, this can be left blank

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