HomeScan helps find your Bluetooth weak spots

A smart home can only be truly smart if whatever system you use can collect data about the state of the home. This important task falls to sensor devices, conventionally wired or connected via a home automation protocol like ZigBee or Z-Wave. With advances in Bluetooth technology, however, the viability of Bluetooth wireless sensors has resulted in much more user friendly options.

Having sensors, which are typically small devices, be truly wireless with decent battery life is a tremendous convenience as it allows for them to be placed where ever they are needed without worrying about wiring or bulky batteries. Bluetooth LE sensors can run for months on a single AAA or ‘Half AA’ battery allowing for easy, reliable operation. The biggest issue with these devices is Bluetooth signal strength. Low strength can result in intermittent or slow response, which can be very detrimental to home automation setups.

One platform that makes extensive use of Bluetooth as a core protocol is Apple’s HomeKit. In order to make the platform accessible to typical home users, Apple opted to use the two most common wireless protocols for compatibility, WiFi and Bluetooth LE. As many HomeKit users have found, Bluetooth device performance is very dependent on good signal strength. But how can you determine the best placement for your sensors?

App Developer Sunya Limited has developed a suite of HomeKit utilities to assist with the operation of your HomeKit setup. One of these addresses the question of Bluetooth troubleshooting by providing a handy Bluetooth scanner app called HomeScan. HomeScan is designed to quickly and easily identify your Bluetooth devices, and provide a portable and data driven means of determining signal issues.

Jumping into the app, we are immediately presented with a list of devices in range, and their signal strength from your iPhone’s current location. The signal is indicated in dBm, or decibels relative to a milliwatt. This ranges from 0 to -100 where 0 is impossibly perfect signal, and -100 is essentially no signal. It’s a bit more involved than that, but for our purposes we can look at a basic range of -30 to -80. Most decent Bluetooth devices will operate well at -80 dBm or more, and everything will have no issues above -70. So you’re looking at a typical operating range of -40 to -80 for Bluetooth sensors and switches. To get more than -40 you’d be basically right next to a device, so it’s not realistic or necessary.

HomeScan shows this signal strength clearly next to each device as both a number and a partially filled ring. It will also try and match devices to your HomeKit configuration and indicate those with a HomeKit icon on the right side. The device name will be shown by default (if it has one), and matched HomeKit devices will try and use the Service Name (what you’ve named it in the Home App).

HomeScan main view

HomeScan main view

HomeScan HomeKit only view

HomeScan HomeKit only view

Tapping the menu in the top right corner will allow you to sanitize the list a bit by selecting HomeKit Only if you only want to troubleshoot those devices. If you’re looking to test placement of a new device though, you’ll need to look at all devices, as your home hubs will not show in the HomeKit list, and those are what you’ll want to test signal to. Note that while the app is designed to assist HomeKit users, it can be used for all Bluetooth devices.

For example, if you want to place a door sensor, you can go to the expected location and hold your iPhone there, then check the signal to your home hub, be it a HomePod or Apple TV. If you have more than one you’ll be able to see the strength to each, keeping in mind HomeKit will use the hub with the best signal and relay it to your primary hub. To troubleshoot a device, hold your phone on top of your home hub and check the strength of the problem device from there.

For this latter case you can tap on a single device in the list to get a full screen view of that one device, giving you an enlarged version of the ring, as well as peak and average signal over time, and a worded rating (eg: Good, Weak, Bad). With this, you’ll note that Weak is in our ‘usable range’, so don’t worry about that too much.

HomeScan device view

HomeScan device view

HomeScan graph view

HomeScan graph view

From this detail screen you can also access a graph of the signal fluctuations. The graph dynamically scales the axis based on the highs and lows of the signal over about a minute. It’s cute but probably less useful than it would at first seem. More useful is the inclusion of a speech cue, which will read out the current signal strength to you. This is handy if you are testing a placement that makes holding the screen towards you awkward.

Having a utility like this can be a huge help in deciding if the location you have in mind for a new Bluetooth device is going to be viable, as well as troubleshooting performance issues with existing devices so you can determine where you mind need additional hubs.

HomeScan is available for iPhone and Apple Watch on the App store, check it our here.