# Device Guideline
The following guide will give you device recommendations and will discuss which devices you should use in your study and which you should avoid. It also includes a guide to get some devices which are not recommended to work. Please check this guide every time before you couple new participants in order to get the latest information about recommended devices, because the smartphone industry is a quickly developing industry.
# Recommended Devices
We recommend that before buying a large quantity of devices, you buy one device of the intended type beforehand and test it with movisensXS.
There are a few minimum requirements for the Smartphone:
- Operating System: Android 4.4 or higher
Other operating systems are currently not supported. Experience Sampling has lots of requirements and building a solid solution for multiple operating systems is very difficult. The iPhone is also too restricted for research purposes. We focus on Android because cheap smartphones are available. Android is also open source and it is sustainable.
- Minimum 1 GB Memory
- Minimum 1 GB internal storage free. The study configuration and the study results are stored in the internal data storage. If multimedia items are used please buy a smartphone with 16 GB internal storage
- Processor: Qualcomm Snapdragon highly recommended with 600 MHz or higher (recommended)
- Battery: 1200 mAh or higher (recommended to achieve a longer battery life)
- A larger display size makes it easier to input text but consumes more power and are not as handy for everyday use. 5" are optimal.
- If you need to transfer the results during the study to monitor compliance, choose a device with 3G mobile connectivity. Please test the data usage and disable all automatic updates. If possible choose a mobile data flat rate.
Recommended android devices because of the good value/price:
|Xiaomi||Mi A2 or Mi A2 Lite||Very low price and pretty good value. Android One program guarantees 2 years of updates.|
|Nokia||Nokia 2 or Nokia 2.1 or Nokia 3.2||Very low price but not the fastest device. Android One program guarantees 2 years of updates.|
|Nokia||Nokia 4.2 or Nokia 5 or Nokia 6 or Nokia 6.1||Very low price and good value. Android One program guarantees 2 years of updates.|
|Motorola||moto g⁵ˢ||Good performance and value.|
|Google Pixel 3a or Google Pixel 3||little more expensive, but with most recent hard- and Android software with 3 years of updates|
A full list of untested, but most likely compatible devices can be found on GSMarena.
# Unrecommended Devices
There are a lot of devices which may not work properly with movisensXS. At least there are devices where you have to configure the device itself heavily in order to get movisensXS to work. Please be sure to check your devices in advance and make the right adjustments to avoid data loss!
Usually you don't always have control of the devices which should run movisensXS (e.g. participant owned devices) and therefore you can't enforce the recommended device list. In this chapter we will list common issues of unrecommended devices and, if possible, give you some solution advices.
# Battery Saver
Some vendors are always trying to squeeze some battery saving features into the firmware with each new Android release and some go so far that they break movisensXS just to get a little more juice out of your device. These devices won't let us do work in the background unless you actively use your device at the time. This affects movisensXS because our whole execution of your sampling scheme is designed to run in the background.
Unfortunately, vendors like Huawei, Samsung or OnePlus implement their own battery savers, usually very poorly written, saving battery only superficially with side effects.
Naturally users blame our developers for our apps failing to deliver. But the truth is our developers do the maximum they can. Always investigating new device specific hacks to keep movisensXS (your sampling scheme!) working. But in many cases they simply fall short as vendors have full control over processes on your phone.
In order to get those devices to run, you have to whitelist our apps from vendor specific battery management. There are a lot of different devices with a dozen of different Android software versions, which will make it difficult to cover every bit of this topic in this documentation.
Therefore, you should check the following sources if you start a study on a new device:
- Dontkillmyapp - Originated to help developers and users to identify affected devices, rate them and give some hints to resolve those issues.
- Undoze - Lists recommendations of a huge amount of devices and vendors to disable battery savers.
- ACR Wiki - List of recommendations for different vendors and devices to disable battery savers originated by the developer of the ACR app. Please be sure while following the instructions on the site to search for movisensXS instead of ACR.
# MediaTek Processors
MediaTek Processors are highly inaccurate in triggering alarms. These processors are not recommended!
There are also a lot of devices from our recommended vendors which have a MediaTek processor for example:
|Nokia||Nokia 2.2 or Nokia 5.1 or Nokia 3 or Nokia 3.1|
So please be sure to check the chipset of your intended device! You can check this information on the official vendor page.
# Android Go Edition
Go edition of Android may not work with movisensXS because the lack of some features which movisensXS will use.
There are a lot of pretty cheap devices, which are officially running Android Go. This is an Android predecessor with a lot of cutbacks in order to make those devices as cheap as possible (intended for developing markets). Please be sure to not buy such a device because it may not support movisensXS.
# Device Check-Up
The following guide tries to give you a good step by step advice to configure and couple your devices, so they will run movisensXS flawlessly. This guide may not be complete because smartphones and their updates are released pretty quick and often. It's also possible that a device which you've tested won't run after you've installed an Android Update. So please be sure to not upgrade your devices while your study is running and also test an Android update before you update all of your devices.
# General Advice
If you plan to buy devices for your study, please buy recommended devices. If you don't have control over your bought devices or you are using participant owned devices, please follow this whole section.
Please also mind:
- If the data transfer does not work as expected, reboot the smartphone, synchronize the movisensXS again and check that mobile data transfer and Wi-Fi is enabled
- Are automatic updates of movisensXS disabled
- Security App may cause problems because they may close the movisensXS app
# Device Check-Up
Identify your vendor, model name and android version
- Go to Settings of your device and check the 'About Phone' section.
Try to match your device with our sources:
- If your device vendor is included on the Dontkillmyapp front page, try to follow the included instructions.
- If your device vendor is not included, please check Undoze or the ACR Wiki and follow their instructions if included.
- If neither of the sources include your device vendor and model or doesn't have instructions, continue the coupling process.
Couple your smartphone and start the informed consent process
- Please activate the Disable Battery Optimizations (optional) checkbox.
Check your smartphone for smartphone warnings on the movisensXS home screen. There are different warnings which will refer to unrecommended devices (it's possible to hide those afterwards):
Instruct your participant
Explain how often and when alarms should happen.
Instruct your participant to contact you if something won't run as expected and let him check that the movisensXS icon is always displayed on the smartphones Status Bar on the top left.
- Study ID
- Participant ID
- Issue description
- Smartphone model
- Android version
- movisensXS version
- and send Debug Logs (You can find this options in the settings, while study is started)
# Known Device Issues
The following issues are known and can currently not be fixed:
- Huawei Ideos X3: The "Play Audio" item does not work properly. The screen get locket by the phone.
- LG D160: The "Play Audio" item does not work properly. The media playback controls do not get removed from the screen.
- HTC One V: The "Record Video" item does not work properly. The video can be recorded, but cannot be played back on the device.
- Samsung Galaxy Tab with Android Version 4.4.2: If the personal messages windows is not fully loaded and the back button is pressed, the app crashes and restarts.