The Remora can be fitted with an HES Magnetic Tamper Detection board. This allows the device to wirelessly detect that it has been detached from the asset.

The HES board works with a magnet that should be firmly glued to the asset. The Remora is fitted over the magnet, aligned with the circular recess in the housing. The HES board detects the magnetic field. If the field is present, tamper is OFF. If the field is lost, tamper is ON.


From October 2016, Remoras are built with the HES board included. If you are unsure, be sure to specify the inclusion of the HES board in your order. Magnets are supplied with the HES board.

To check if an HES board is fitted, look underneath the main PCB for a small separate PCB placed over the housing recess and connected by a 3 wire harness.


  • Glue the supplied magnet to the surface of the asset. 
  • Place the Remora over the magnet, allowing the magnet to fit into the recess underneath the Remora.
  • Ensure that the magnet firmly adheres to the surface of the mount point. If it is not stuck strongly to the mount point, either magnetically or with the aid of adhesives, it may instead stick to the Remora. 
  • Ensure that it will reliably separate from the Remora during tampering, so that the alarm will be triggered.

Setup on OEM

The ‘Tamper Detect’ indicator is mapped to a digital input, and goes high when the magnet is removed. The default mapping is to digital input 2. This will be setup by default.

From firmware version 1.35 onwards, the default response to a tamper event is to log the event, attempt a single GPS fix, and attempt a single upload. Previous firmware versions do not allow the action to be configured, and default to retrying the GPS fix and upload until they succeed, with increasing back-off times. You must choose an action that at least logs the event if you wish to receive an alert in TG.

Setup on client software

Use digital input 2 for the tamper indication, similar to this:


Creating an alert
To alert when a tamper is detected, you would want to setup the alert to fire on Digital Input 2 turning on.

In Telematics Guru, that looks like this:

Using the HES board to force a connection

The HES board is useful if you need to force an upload. Trigger the tamper upload by moving a magnet into range. If configured correctly, the Remora will attempt to connect to the server.

Disabling Tamper Detection

From firmware version 1.35 onwards, it is possible to disable the tamper detection feature in the system parameters on OEM. If the HES board is fitted, disabling it saves approximately 0.75% of a set of Alkaline batteries per year. If the feature is disabled in OEM no tamper events will be logged, no alerts will be triggered in TG, and the tamper digital input will always read low.