iOS Compatibility

Before we go into the details, we want to discuss the smartphone and tablet options available. For the latest Harry's app versions, iOS9.3 is the minimum OS level required. We try hard to always support the current and last major OS version. With 9.3 we are well beyond that currently. We recommend to always use the latest iOS version. There is no need to hop onto it on day one, but after a few weeks it will simply be the version most users use and the basis for our application testing too.

The minimum iOS requirement makes an iPhone4S the last generation supported. The iPhone4S is certainly dated and may run into limits when using too demanding add-ons like high update rate GPS / OBD or when doing video recording in parallel. The iPhone4S is the device with the best video support for LapTimer. This sounds strange as all later models introduced great video features. Oddly, many of the optimizations were not in favor of track day users moving fast around a circuit–instead of focussing a moving object. You will get more "jello effects" for the latest generations compared to the 4S. Except this, the iPhone 5S, iPhone 6, etc are the perfect track companion and the recommended smartphones for LapTimer user. They have the processing power necessary for all the features, have big enough screens, and enough main memory to process videos.

In case you want to use an iPod touch, the 5th generation (and later) is supported. Please keep in mind you will need an external GPS on top, iPod touches do not have a GPS chip built in. The iPod touch 5th gen comes with 512 MB main memory - which is the minimum required for video overlaying and processing.

iPads make great track companions too. Like iPod touches, the Wi-Fi only iPad versions do not come with a built in GPS chip and need to be extended by an external accessory (see below). All iPads except the first generation are supported currently. An iPad or iPad mini with 1 GB of main memory is recommended. Most of Harry's apps are optimized for iPads and feature additional layouts to fully use the large screen.

Storage size in another spec you need to take care about. While a 16 GB device is fine to use LapTimer in standard mode (no videos), it is getting a cumbersome operation once you start working with videos. Keep in mind, a minute of Full HD video requires approximately 190 MB of storage. This means a typical session of 20 minutes will require around 4 GB for the raw video alone. Exporting an overlaid video will double this requirement. The recommendation when recording and processing videos is to go for a 64 GB or better device from the beginning.

A stable mount is the only accessory besides a power supply one needs to start using LapTimer. A mount is used to install the smartphone in a place it has both perfect operating conditions (like good GPS reception and a low amount of vibrations) and can be monitored by the driver. Please never use LapTimer without a mount - like placing the smartphone in your cloth or in your car's center console. You need to be serious about this when attending track days.

There are plenty of mounts available today, in all colors, shapes, sizes, and prices. Only a very small number of mounts is well suited for track or other heavy duty use. We have tested dozens and were almost always disappointed. The selection shown here covers some mounts produced by RAM Mounts(R). RAM Mount has an incredible big portfolio for all kinds of vehicle types, mounting positions, and smartphone form factors. They are not the only ones to provide usable solutions, neither all of their mounts are suitable for track use. So please read this section as our recommendation on devices we have experience with. Use a slightly different one (e.g. one made from composite instead of aluminium, or one with a smaller suction cup), and you will get completely different results.

As introduced above, RAM Mount provides several other options. The above two examples are the ones used most frequently. In case you do not want to, or cannot use a suction cup, you may opt for a RAM Flex Adhesive Base with 1" Ball (RAP-B-378U) or a RAM Rail Base (e.g. RAM-B-231U).

All iPhones supported by LapTimer come with an internal GPS sensor and can be used for lap timing out of the box. However, if you are interested in higher accuracy and use LapTimer a lot, I recommend the use of an external GPS accessory. For iPod touch devices and iPads (non-3G) it is a different story. They do not have an internal GPS sensor (network triangulation only) and thus cannot be used without additional sensor support.

For iOS devices any Bluetooth GPS connected needs to be Mfi (Made for iPhone) certified. This is the reason most GPSes you can buy will not work with your i-device. In addition, there are two approaches for LapTimer to receive data from GPS devices: direct access or using iOS's Location Service. The later works with all Mfi GPSes but limits data to what is passed through by iOS and limits update rates in addition. This is the reason we recommend GPSes connected directly and list these only.

Dual XGPS 160 (Sky Pro)

The Dual XGPS 160 is LapTimer's work horse currently and will provide very good data recordings for most users. It delivers 10 positions per second (10 Hz) and utilizes both the U.S. GPS and the Russian GLONASS system. Using both systems has its advantage in having nearly double the number of satellites available–yielding better accuracy and better lock stability. The XGPS 160's ability to connect to several devices at once does not look like a key feature initially, but saves you from conflicts when accessing it with more than one smartphone. LapTimer is fully integrated with all of this device's features.

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Legacy: Dual XGPS 150A

The Dual XGPS 150A is the 160's predecessor and has been the former recommendation for LapTimer. Other than the 160, it comes with a 4 or 5 Hz GPS only chip (i.e. no GLONASS support) and connects to one smartphone at a time. In terms of integration and capabilities, we consider it the same value for money like the 160, making it the recommended solution for price sensitive users. NB: the XGPS 150A often comes with a 1 Hz firmware preinstalled. To enabled 4 or 5 Hz operation, please sign up for the fast firmware here.

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As introduced above, Mfi devices not mentioned in the list are not directly integrated into LapTimer and are not recommended. We add direct integration for all devices we get support by the manufacturer. Please contact the manufacturer in case you want to use their devices. In case you want to use one of these devices nevertheless - they are available using iOS's location service, but will show up as "iPhone GNSS": Garmin Glo 2, GNS (all devices).

With introduction of our developer program, device manufacturers and other 3rd parties can add support for arbitrary sensors to LapTimer and friends. The following GPS and GNSS devices are predefined in our apps and can be used "out of the box". As we do not have access to this devices, any support needs to be provided by the manufacturer or by the person who provided the integration using our developer program. ReDrive BLE (20 Hz GPS) integration has been contributed by Mateusz Szczurek. RaceHF (high update rate GNSS sensor) integration has been provided by 李政 (Le Zheng).

For combined GPS/GNSS and engine sensors, please see the OBD II and combos section.

Last not least there are two legacy GPSes LapTimer supports: PosiMotion's G-Fi and Tom Tom's first generation car kit. Both devices are 1 Hz only and are not available any more. Nevertheless, we keep support included already. In addition, any GPS making an NMEA stream available via Wi-Fi can be connected. Samples are several marine devices and the π-GNSS.

A final remark on jailbroken iPhones: in case your device is jailbroken, there are two solutions available to connect any NMEA GPS (i.e. not Mfi) to iOS: roqyBT and BTstack GPS. GPS mouses connected using this solutions will not benefit from LapTimer's direct integration like Satellite View, but work otherwise. We do not support this configurations and discourage the use of jailbroken devices in general.

The following section shows a number of genuine OBD II dongles supported by LapTimer. I'm aware there are a lot cheaper ELM327 copies around but I discourage their use. Although LapTimer will connect to most – if not all – ELM327 BT SPP and WiFi dongles, my recommendation is to spend the money for a genuine ELM 327 dongle like those listed. It really makes you feel better because you know what you connect to your car's bus. Furthermore we consider all these knock offs to be product piracy hurting those who invest in innovation.

Besides the discussion below, we regularly run benchmarks on OBD II update rates achieved with LapTimer.

With introduction of our developer program, device manufacturers and other 3rd parties can add support for arbitrary sensors to LapTimer and friends. The following OBD II / engine or combo adapters are predefined in our apps and can be used "out of the box". As we do not have access to this devices, any support needs to be provided by the manufacturer or by the person who provided the integration using our developer program. airVentDisplay (BMW E46 CAN and GPS data) integration has been contributed by This email address is being protected from spambots. You need JavaScript enabled to view it..

Today's smartphones come with great internal cams contributing awesome material to add overlays using LapTimer. Nevertheless, there are some limitations making external solutions interesting. For spectacular driving videos, a wide field of view is what you want. Action cams listed below all come with wide angle objectives. For iPhones in particular, there is another reason you may opt for an external solution: although the cams became better and better for each generation, video stabilization and other "smart" controls are not optimized for track use. They are made to focus a moving object, not for a fast moving landscape. We try to disable as much as possible, but late iOS and Android versions treat all of this as 'hints' and will override LapTimer settings if they believe it is appropriate...

Opposed to LapTimer, Harry's Camper uses external cams to make a rear view available. There are cheaper solutions available than action cams, but why not use them if you have one anyway?

I'm contacted frequently with the question if action cam XY is compatible with LapTimer too. The answer is "any external action cam recording H.264 encoded HD and FullHD videos can be used to provide video which can be overlaid by LapTimer". This statement however focusses on compatibility of video material, not remote controlling or integrating the cam with LapTimer. A tight remote controlling integration including easy synchronization of data recordings and video is provided for the above cams only. For all others, the cam needs to be operated manually, synchronization needs to be added by the user, and transfer of footage from cam to smartphone is a manual process too. All of this is described in Video Documentation.

Please understand I will not add further cam support as long as the cam manufacturer does not offer a public developer program, or offers individual support for integration. I contacted many in the past but found most of them not interested in 3rd party support.

When talking about tire management, we see two major dimensions: Tire Temperature Monitoring Systems (TTMS) and Tire Pressure Monitoring Systems (TPMS). The later is mandatory for new passenger cars today, so we see a quick adoption. This type of sensors is focussing on avoiding accidents, fuel economics, and on detecting a hazardous state of the tires. Oddly, access to this data is not standardized, so adding some after market sensors will be required to allow access by our apps. Expect for blow outs, pressure management will work fine at low update rates.

Temperature monitoring is by far more interesting when on track. An optimized tread temperature is a vital measure for optimized grip. When too low, grip will be low, and when too high, tires will wear very fast. Especially with high update rate sensors (5 Hz and more), it is possible to detect critical driving conditions on corner level.

Fitness and health sensor are discussed everywhere - a real trend. In case you are interested in how your body is performing on track, you may opt for one of the options getting available. Support for vitality parameters is limited to heart rate measurements currently. Nevertheless, we expect we will add others in the future. Any health or fitness sensor to be used needs to deliver its data to iOS's Health app. LapTimer will not access any sensor directly but will retrieve data from Health app only. We are sensible to privacy for health data, from our Privacy Policy: "Any health kit data is displayed only and not stored locally or remotely, neither is it shared with any party."

The list below is an arbitrary selection from sensors we got our hands on. Different to other sensor types described on this page, we have no market overview yet. In case you find a sensor showing good results and feeding data into Health Kit, please let us know.

Apps featuring weather options come with support for an arbitrary number of Texas Instruments' SensorTags. This little Bluetooth Low Energy device is coming with a variety of sensors, namely temperature, humidity, pressure, accelerometer, gyroscope and magnetometer. Due to the use of BT LE, the battery included has enough energy for month and years of operation. By adding more than one tag, you can measure different areas - inside and outside - in parallel.

In addition to environmental measurements, Harry's Camper uses the accelerometer included to allow remote leveling. The sensor is sitting inside the caravan and sends information on corrections necessary to the app the user carries around.

All environmental sensors shown here use Bluetooth Low Energy. There is no pairing required like for regular Bluetooth accessories. NB: They will not show up in iOS's list of paired Bluetooth devices. Nevertheless, to use the sensors, Bluetooth needs to be turned on. The first iPhone generation featuring Bluetooth Low Energy is the iPhone4S.