Defining Artificial Operating System Sensors


In addition to “real” sensors Apple has built into your Mac, Hardware Monitor can also monitor other operational values of your computer. This is done by creating artificial software sensors, which are called Probes.

You can define an unlimited number of probes that monitor the following aspects of the operating system:

Note: If you are using internal “hot-swap” drives, or external eSATA drives, a probe of the type S.M.A.R.T. drive verification status will also register a hard disk error when you are switching off or removing the drive.

Hardware Monitor Preferences: Probes
Hardware Monitor Preferences: Probes

Creating and editing probes

Creating a new probe is possible with the section Probes in the Preferences window of Hardware Monitor. Select the desired type of probe, then press the button + below the left bottom corner of the probe table. If it is necessary, Hardware Monitor will ask for additional data to create the probe, e.g. the processor number for a CPU load sensor, or the hard drive for a virtual S.M.A.R.T. sensor. The probe will be added immediately.

Probes behave the same way as “real” sensors. You can use them without any restrictions, for example to define alerts, to record history data, to display them in output windows, etc.

To delete a probe, select its entry in the table, then press the - button below. History data of a deleted probe will be deleted as well. It is not possible to recover history data of a deleted probe even if you attempt to recreate the same probe later.

It is not possible to create two identical probes, i.e. probes of the same type which monitor the very same object. Hardware Monitor can create probes for the local computer only. It is possible to monitor probes on remote computers as well, but in this case you’ll have to create them with a copy of Hardware Monitor running on the remote computer first.

Importing and exporting probe definitions

If you have created a complex setup of artificial sensors, you might like to reuse this definition on other computers of the same model series. This is possible even if you don’t use a macOS network with roaming user accounts: You can export and import the probe definitions using files.

To export the current list of probe definitions, select the menu item Export probes… from the pull-down menu Import/Export in the upper right corner of the pane Probes. After specifying a file name, the definitions will be saved.

To import a file with probe definitions, select the menu item Import probes… from the pull-down menu Import/Export. After selecting a file, the definitions will be loaded, hereby replacing all your current probes.

It is recommended to use this feature among computers of the same model series only. If you are trying to import a probe definition which refers to a device unknown on the current hardware (like a network interface, or an electrical sensor unavailable on that system), Hardware Monitor will either discard this probe automatically, or create a non-working probe which always gives the reading “—”, depending on case. After importing artificial sensors from a different model series, it is recommended to review the list of probes afterwards.