Our devices offer a number of different inputs including:

• Digital Inputs
• Analogue (0-30V) inputs
• 4-20mA
• Bluetooth®
• I2C
• 1-wire
• SDI-12
• RS232
• RS485 

These interfaces allow for a wide variety of various sensors to be connected to devices for applications such as:

• Tank Level Monitoring
• Fuel Level Monitoring
• Temperature Monitoring and Cold Chain
• Door+Gate Open/Close
• Battery Level monitoring
• Run hours/odometer monitoring
• Agricultural Monitoring (soil moisture,temp,rainfall)
• Axle load monitoring
• and many more

Device Selection

Many devices in our current range are able to read various sensors, so it may be confusing as which to choose. 

In general, we have some simple decisions to make when selecting a product. 

1. Power – Do we have the option to hard-wire? Or do we need a battery powered device
   1. This will largely dictate the product we choose
   2. Hard-wiring will allow sensor readings to be uploaded more frequently for real-time monitoring and alerting
   3. We generally need to be more efficient with when we choose to sample/upload on battery powered devices to get the maximum battery life
      
      
2. Required Sensor
   1. We may need to use an SDI-12 sensor for example in which case the only option is to hard-wire with the Hawk
   2. Generally though there is a large array of Bluetooth Low Energy (BLE) sensors available to fit a given use case.
      
      
3. Tracking and Sensor reading update rate
   1. As per 1b – for live updates go with a hard wired device
   2. The Hawk does not support trip tracking – rather periodic sensor/GPS updates

Check each individual product’s data sheet for the full specification, but inputs are collated below.

Historic devices are shown for completeness, but many are no longer in production. Current products in Bold. 

Click the hyperlinks to be taken to relevant documentation. 

Input Descriptions

Digital Inputs:

Used to determine on/off status. Will be registered as 0 (off) or 1 (on).

Typical applications include panic buttons, door open closed, monitoring engine on/off, run hours when connected to a PTO

Analogue Inputs:

Can be connected to a variety of sensors e.g. Temp Sensor, ultrasonic sensor etc, that output a certain voltage based on the temp/distance etc. This can be thought of as a voltage input.

Can also be used to read 4-20mA signals when combined with a sense resistor.

4-20mA:

Common sensor output. Sensor will output 4mA when at the minimum of its range, and 20mA when at the maximum.

BLE:

Some Digital Matter Devices have a BLE 5 Module on board. This means that any sensor that uses Bluetooth could be integrated into the device FW so the sensor can be read.

I2C:

Inter-IC communication. Low level communication interface which is used on many different sensor types.

SDI-12:

Commonly used in the Ag-Tech space for soil moisture probes etc. 

1-wire:

Generally used for i-Button Tags and readers. But some 1-wire sensors (e.g. temp) exist

What Sensors do DM products support:

The following table lists some sensors we have seen in use with our devices, or integrated at the request of partners. This is not an exhaustive list, and not all have been thoroughly tested by DM, instead we rely on the feedback from our reseller partners.  

Integrating sensors across multiple devices requires firmware development per device – as such a single sensor integration is not rolled out across all devices with the same input immediately (or even at all if it is not required). 

If you want to use one of the above sensors with another device, contact us.

I need to use a sensor that isn’t listed here, what are my options?

For users on 3rd party platforms – the quickest path forward is generally a BLE sensor. Nearly all tags can be read and their data reported to the server with no integration effort.

If an application requires a particular sensor that is not currently catered for, DM can integrate sensors. Typically a sensor which utilises one of the above inputs can be integrated with firmware development. 

Most common are I2C sensors. I2C is a low level communication interface, so simply connecting an I2C sensor to a product with an I2C input in general will not work – the firmware must be modified.
Note for these sensors, The sensor should be able to be powered by a 3.3V source. As this is what is available to power sensors on DM devices. If it requires greater than this it will need to be powered externally to the device.

Please contact DM so that the sensor can be integrated into device firmware. Similarly if a particular Bluetooth® sensor is desired, contact DM for integration information.