The Barra Range of devices features a Hall Effect Sensor, and includes a magnet. 

A Hall Effect sensor can detect the presence of a magnetic field. So the device can detect whether the small magnet shown below is within the housing recess or not.

This enables 2 key features/modes - Activation Mode and Tamper Detection

• Activation Mode
  • While the magnet is present, the device remains in a super-low power ‘dormant’ state - and is effectively shut off. 
  • The device will not attempt to obtain a location fix, or upload.
  • This allows devices to be provisioned (SIM inserted, batteries inserted, device sealed) and shipped to users in this state
  • When the user wants to install the device, they can simply remove the magnet and it will begin operation.
  • If the magnet is reinserted, the unit will log that it has been deactivated and then go dormant. 
     
• Tamper Detection
  • When installing the device, the magnet can be glued or otherwise attached to the asset. 
  • The Barra is then installed over the magnet (the magnet fits inside the housing recess).
  • If the Barra is removed from the asset - the Barra will immediately detect that the magnet is no longer present and send an alert. 

Configuration

The Barra ships in Activation Mode as standard, meaning…

1. The magnet must first be removed when installing in order for the device to connect
2. If the magnet ever gets reinserted, it will log that it has been deactivated and then go dormant again

The parameters can be edited to set the ‘Sensor Function’ to the following:

• None (disable the Hall Effect sensor) - This saves a small amount of energy and is worthwhile if once deployed you are not making use of Tamper Detection
• Tamper Detection
• Activation Mode

The specific timing of applying parameters, or a parameter template should be considered, particularly when the device is in Activation Mode, with the magnet inserted. New parameters can then be applied which will only take effect once the magnet is removed and checks in.

Example Process:

1. Ensure that there is no connector applied on the device in Device Manager (to ensure that initial messages aren't sent to the end platform, possibly incurring fees).
    
2. Remove magnet, install batteries, install SIM card.
    
3. Observe LEDs flashing on the board, observe activity with Device Manager or the Installer Page.
    
4. Update to latest firmware, apply desired parameter templates, and wait for Device Manager to show slot synchronization.
    
5. Seal housing, re-insert magnet (if using activation mode).
    
6. Wait until the device logs that it has been deactivated.
    
7. Apply the connector in Device Manager.
    
8. (if using tamper mode) Update system parameters to enable tamper detection in device manager.
    
9. Device arrives at deployment site, magnet is removed, activating it.
    
10. (if using activation mode) Collect the magnets and use them to affix high resolution printouts of Digital Matter hardware to your refrigerator to showcase them to friends and family.
     
11.  (if using tamper mode) Review the Installer Page until the “Parameters” attribute resolves as okay.
     
12. (if using tamper mode) Glue magnet to asset, fit device over the magnet.
     

System Parameters

The ‘Sensor Function’ dropdown can be found in the ‘Magnet Sensor’ tab; which can be accessed by adding ‘Advanced Parameters’ in the ‘Edit System Parameters’ menu.

Activation Mode (Default)

1. Magnet present = device is dormant and offline
2. Magnet removed = device will operate
    

Disable Magnet Sensor

Turn the Hall Effect Sensor off, if it is unused, to save energy. 

This also has the benefit of preventing the device from being inadvertently disabled after deployment if the magnet is reinserted. 

Tamper Detect

• Tamper Detection can be enabled
• Select a digital input to be set when the magnet is not present
• Set the action (i.e. upload to alert on the server)
   

Admin Parameters

The ‘Allow Activation Mode’ dropdown can be found in the ‘Magnetic Sensor Override’ tab which can be accessed by adding parameters’  in the ‘Edit Admin Parameters’ menu.

Setting ‘Allow Activation Mode’ to No will prevent the device from going dormant (offline), irrespective of what system parameters are set. 
This allows for a failsafe mechanism, as simply applying the wrong system parameter template cannot cause a device to go dormant. 

Tamper Detection Payload and Alert Example

For the Tamper Detection setup below, Digital Input 7 will be set to ‘1’ when the magnet is not present. 

In addition, Bit 6 of the Device Status Field is set. 

{
"date": "2022-11-02T07:12:49Z",
"device": {
"sn": "415828",
"prod": 85,
"rev": 1,
"fw": "1.21",
"iccid": "89610185002696330407",
"imei": "351358810440518"
},
"sqn": 8617,
"reason": 3,
"lat": -31.9476768,
"lng": 115.8195775,
"posAcc": 13,
"posInfo": {
"Src": 6
},
"analogues": [
{
"id": 1,
"val": 4324
},
{
"id": 3,
"val": 2600
},
{
"id": 4,
"val": 18
},
{
"id": 5,
"val": 4289
}
],
"inputs": 129,
"outputs": 0,
"status": 67,

Tamper Alert in Telematics Guru

The ‘Magnet’ Status Flag is mapped to Digital Input 30 in Telematics Guru by default. 

Configure an alert on this digital input in order to set up a tamper alert.

 

 

Provisioning Workflow Examples

Parameters applied while the device is dormant (magnet present in Activation mode) will queued and applied when the device first connects in (i.e. magnet removed for deployment).