Using Single-App Mode for Long-Term Noise Monitoring

Using Apple's iOS device supervised mode, an iOS device can be set up to run a single app, and even launch directly into that app after rebooting. The app cannot be shutdown, and no other app can be run. Siri can be disabled. The home button can be disabled, and much more. This is ideal for setting up a system for long-term noise monitoring.

Using a third-party device management service, the device location can be monitored, apps updated, and it can even be remotely rebooted, with the app restarting automatically after the reboot. We recommend using SimpleMDM for this service. They charge a small fee, currently no more than $3/month per device. Note that you will have to have internet connectivity to be able to remotely manage a device, either through WiFi or a cellular connection.

Single-app mode, using a supervised device, opens up the possibility to use Apple hardware as the basis for solid, reliable long-term noise monitoring, where the device can be managed from a remote location.

This method is superior to guided access mode, as it provides for remote device management and for automatically restarting the app after rebooting. You will need a Mac computer for this process.

Overview

Follow these steps to set up an iOS device in Single-App Mode. They are described in detail in the sections below.

  • Buy a dedicated iOS device and microphone. You don't want to do this on a device that you use for other purposes
  • Activate Supervised Mode using Apple Configurator 2
  • Turn off notifications on the device to prevent other potential interruptions
  • Install the app, typically the SPL Graph or the SPL Graph Pro standalone app (not AudioTools) and adjust the settings in the app for your noise logging case
  • Subscribe to a third-party Apple Mobile Device Manager Service, enroll your device, and configure the device for single-app mode using the device manager

See below for full instructions on each of these steps. 

Hardware

Decide which iOS device to use. We like iPad Mini, but other choices will work. Get the cellular data option if needed, and decide how much memory you need. Audio and video files can use a lot of space, so take that into account.

Pick your Studio Six Digital microphone option, from iTestMic2, iPrecisionMic, or iAudioInterface2. Plan how you will power the system, whether using AC, battery, or solar. Get a Lightning extender, If needed. If required, get the system type certified.

Once you have your hardware, you can complete the set up process.

Activating Supervised Mode

This is the first step in setting up an iOS device for remote management and single-app mode. Note that this process will completely wipe the device, so if there is any data that you need to get off the device, do it now. Once this step is done, the rest is fairly easy.

Before starting this process, go to Settings on the device, and turn off "Find my iPad/iPhone" and then log out of iCloud and iTunes.

Next, follow these instructions from SimpleMDM, using the section for "Supervise a Device with Apple Configurator". This is probably a good time to setup an account with SimpleMDM, using their free 30-day trial. They have excellent support! 

Activating Supervise Mode information from SimpleMDM:

Apple Configurator is an OS X application. To supervise a device with Apple Configurator, you must have an OS X computer and USB cable available. Each device that is to be supervised will need to be connected to the computer. 

NoteTo get the URL mentioned in step 7 below, if you have signed up with SimpleMDM, you can go to the "Devices" page in SimpleMDM, tap the blue square "Enroll" button, and then tap the blue "Show Enrollment" button. Copy the URL on the right side of the screen.

  1. Download the latest version of Apple Configurator. We’re using Apple Configurator 2.4 in this guide. https://itunes.apple.com/us/app/apple-configurator-2/id1037126344?mt=12
  2. Attach your iOS device to the computer using the USB cable.
  3. Start Apple Configurator.
  4. In the “All devices” view, click the iOS device.
  5. Click “Prepare”
  6. Select “Manual” from the “Configuration” drop down
  7. On the “Enroll in MDM Server” screen, optionally define an MDM server using your SimpleMDM enrollment URL copied above.
  8. On the “Supervise Devices” screen, make sure that the checkbox next to “Supervise devices” is checked.
  9. Add the details of your company on the following screen if desired.
  10. Generate a supervision identity when asked to do so if you haven’t already.
  11. Click the “Prepare” button once you reach the end of the dialog boxes.
  12. The device will be prepared and reset.

iOS Device Configuration

Now that Supervise mode is set up, you can turn off notifications, download the app, and get the iOS device all ready for single-app mode. 

Follow our guide for preparing a device for noise logging. Not all of these steps are crucial, but this is a good time to clean up the device to prevent an interruption from coming in.

Download SPL Graph, or SPL Graph Pro. You need one of these if you want the app to start up automatically into noise logging mode after a reboot. 

We recommend using iCloud to transfer files remotely. If you are using it, sign into iCloud now on the device, but turn off everything except Keychain, Find My iPad (iPhone), and iCloud Drive. Leave SPL Graph access turned on.

Set up SPL Graph for your noise logging use case. You can always change these later, but this is a good time to get it ready for noise logging. This is where you set up the octave logging mode, time resolution, Ln mode, audio/video triggers, and time limits.

Make sure you turn on "Start Recording When App Opens". This option appears on the Auto Save Setup page in SPL Graph.

This is a good time to run some tests, and make sure everything is operating as you want it to, before locking the device into single-app mode. Proceed to the next steps when you are satisfied that all is good.

Set Up the Apple Mobile Device Manager Service

Apple has a very rich and complex server-based system for managing enterprise devices, and although it can all be done for free, we highly recommend using a third-party MDM (Mobile Device Management) service. We have been very happy using SimpleMDM and recommend using their service.

You can sign up for a free 30-day trial, and while you are working through setting up your device they are available to provide excellent and timely tech support. You can start with their "Planning Your Deployment" support page, or just dive in to the device management screen, which appears after you sign up

From this page, if you have entered the URL in the Apple Configurator setup, your device will already appear in the list. If not, you will enroll your device, following the instructions that appear after you click the "Enroll Devices" button.

Once the device is enrolled, you will want to create a configuration that will be applied to it, for noise monitoring. 

Click the "Configs" button on the left, and then select "Add Profile" on the right. Select "App Restrictions", and "Only Allow Restricted Apps". Click on "Add Apps", and type SPL Graph, and select the app that you will be using. Click Save.

Now, create a new Group on the devices page. This is where you setup all of your restrictions and policies that you will be applying to your iOS device. You can use it for more that one iOS device, if you are setting up a group of devices. Click the edit button to the right of the Group name, and look through all of the tabs that are there. Pay special attention to the Restrictions page, turn off anything you don't want to be enabled, like Siri, and then at the bottom right, click the "App restrictions" selector and pick the Config that you created above.

Finally, drag your device (or devices) into the new Group, or select the device using the checkbox and use the small menu on the upper right and select "Assign to Group".

To get started, select the device using the checkbox, and then use the menu in the upper right to reboot the device. The app should start running, and noise logging should begin.

Managing a Device Remotely

Now that everything is setup and running, you can remotely manage the device, including doing things like rebooting it remotely, updating the iOS version, or even shutting the device down (but you can't wake it back up if you do this). You can also get information about a device, such as its location, by clicking its name.