Compatibility / Accessories


All iPhones except the first generation 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.

This page discusses several solutions available in the market. Only a small number of combinations is supported from my side. As the battery drains fast with all features enabled, an external power supply is recommend in all configurations.


  1. Works out of the box

  2. AGPS, fast initial acquisition

  3. Pretty good on 4G, 4GS, 5

  4. Comes "for free"

  1. Limited position / timing accuracy

  2. Problems with high speeds

  3. No GPS for iPod touch, iPad Wifi

Recommended Configuration

Copyright © 2006-2015, Harald Schlangmann. All rights reserved. Last revised: 20th May 2015

GPS Configurations

Currently, Apple does not allow to connect arbitrary GPS bluetooth devices to iPhone / iPod touch devices. As there are several MFI certified devices available today, that is not so much of a problem.

In case you go the jailbreaking path, YOU can add arbitrary GPS devices. Current Recommendation to connect these is using roqyBT4. The downside is the jailbreak necessary, the ugly Cydia interface and purchase process, and the overall fragile construction (several pieces of hardware and software need to work together).

I need to finish with the statement that I do not like and do not support jailbroken installations as I cannot give any guaranties on proper operation.

  1. Inexpensive for a Wi-Fi device

  2. Standard ELM 327 communication

  1. Due to Wi-Fi usage, high power consumption for iPhone / iPod

  2. Uses AdHoc Wi-Fi mode blocking parallel connections (e.g. GoPro)

OBD II Configurations

PLX Kiwi 2 Wifi

Recommended Configuration

  1. Standard ELM 327 communication

  2. Supports several network configurations, thus allowing other
    Wi-Fi devices to work in parallel

  3. Fastest OBD adapter available

  1. Wi-Fi configuration necessary

  2. Due to wifi usage, high power consumption for iPhone / iPod

OBDLink MX Wifi

Recommended Configuration

  1. Very good positioning accuracy

  2. iOS and other devices supported

  3. 5 Hz update rate available

  4. High timing accuracy (real time)

  5. Satellites info available

  1. Additional investment ± US$ 100

Recommended Configuration

  1. Very good positioning accuracy

  2. iPhone, iPod touch, iPad supported

  3. Reuse of existing GPS devices

  4. Full timing accuracy

  5. High update rates available

  1. Requires jailbroken device

Not supported / rated

  1. Very good positioning accuracy

  2. Power supply included (USB)

  3. iPhone, iPod touch, iPad supported

  4. 5 Hz update rate available

  5. High timing accuracy (real time)

  6. Satellites info available

  1. Additional investment ± US$ 80

  2. Uses old 30-pin dock connector

Recommended Configuration

Harry's Choice

Despite all the accessory discussions on my forum, and the ratings below, I receive questions on recommended configurations VERY frequently. So to make my life easier, here is my personal choice of devices. This section is regularly updated. Please note that today's best is probably second best tomorrow, so please don't make me responsible if things change ;-)

iPhone5 or later. As an inexpensive alternative, you may go for an iPod touch (5th generation or later) plus an external GPS.

Important: in case you plan to record video or use one or more external sensors at a time, an iPhone4S or an iPod touch 5th generation is the entry level currently. For video recording, please plan a 32 or 64GB device.


RAM Mount RAM-B-166U  (add the cradle matching your iPhone)


XGPS160 (10 Hz) for any iPhone (and other smartphones), or Racelogic's 20 Hz VBOX Sport for professional use


Yes, inevitable

Power Supply

No, that's evil; enjoy simplicity, or start programming yourself



GoPoint Technology's BT1(A) or - in case you prefer a wifi based dongle - OBDLink MX

  1. Parallel PID requests supported in LapTimer GrandPrix edition

  2. Seamlessly connected using Bluetooth, auto power off

  3. Mfi certified, compatible to all iOS devices

  1. Due to BT a little slower than Wi-Fi devices

GoPoint BT1/1A (and GL1)

Recommended Configuration

There are several other GPS devices around that can be connected to the iPhone (i.e. they are Mfi = Made for iPhone certified). Please consider all of these devices to get a lower rating compared to the above devices.

The Bad Elf GPS (★★★★☆) is around for some years already and has evolved over time. The device features a 10 Hz update rate that can be measured by LapTimer. The very odd thing about the Bad Elf is it does not make it's services available through an API like all of the above devices. An API has been announced for years, but has never been delivered. Due to the connector change (Lightning), the device needs an update now or will vanish fast.

TomTom (★★★★☆) has stopped production of their original car kits (there has been one for the iPhones3 to 4S, and one for the iPod touch) including a GPS chip. The current devices - named Car Kit too - is a power supply and handsfree telephony device only, so please do not mix it up with the above device. In case you can get your hands on one of these it is still a decent option. In case it is used, check the mount is stable.

There is a number of other devices around delivering 1 Hz through BT or a cradle / 30 pin plug. As they do not have any particular advantage compared to the recommended ones, they are listed here only: GNS 5879 Mfi, GNS 1000 Mfi, Orange Gadgets i360 (outdated), Magellan Premium Car Kit, Dual XGPS300/XGPS251(outdated). The GNS features a 5 Hz chip but does not deliver this update rate through Apple's location service.

Kind of an anthology of LapTimer is the PosiMotion G-Fi (★★★★☆). At the time of its production, it has been the only external GPS available for iPhones. Connection has been implemented using Wifi and it had a direct integration into LapTimer. It featured 1 Hz update rates but delivered much better accuracy compared to the internal GPS (iPhone 3G at this time).

A new kid on the block is the Garmin Glo (★★★★☆). It is announced to featured 10 Hz update rates although it is not able to deliver this through Apple's location service (we measured 3 or 4 Hz only). Until a better integration with Apple - or a direct integration to LapTimer - is available, this relatively expensive device is not recommended.

GPS for Jailbroken Devices

  1. Very good positioning accuracy

  2. iPhone, iPod touch, iPad supported

  3. 20 Hz update rate available(*)

  4. Designed for track use

  5. High timing accuracy (real time)

  1. Additional investment ± US$ 400

Recommended Configuration

(*) Requires LapTimer Grand Prix Edition (starting v17). Other editions will connect to the VBOX Sport through Apple's location services and get 10 Hz only. Due to the high bandwidth needed, it is not recommended to use other BT devices at the same time.

  1. Very good positioning accuracy

  2. iOS and other devices supported

  3. 10 Hz update rate available

  4. High timing accuracy (real time)

  5. Satellites info available

  1. Additional investment ± US$ 150

Recommended Configuration

For compatibility statements on our new Android version of Harry's LapTimer, please follow Android Compatibility. This page is on iOS compatibility only.

Details and Background Information

In case you want to know more about the options before you order from the links above, here are the details on the individual devices. This section starts with an introduction to GPS devices, for OBD dongles, please scroll down. But we start with some general directions one needs to understand when adding accessories to iOS devices:

Preferred Partners to order from

There are some Partners I recommend to order the above devices from. This links are no "best price" benchmarks, but are based on my knowledge they will service you well. Important: using the links will initiate a contractual relation between you and my Partners, not between you and me (I'm not in the hardware business).

Order your XGPS from Dual Electronics Corporation.


Order your RAM Mount RAM-B-166U from Amazon Deutschland. Add either an iPhone4/4S cradle (RAM-HOL-AP9), or an iPhone5/5S cradle (RAM-HOL-AP11). For motorbikes, check the RAM-B-176 (plus cradle again).


For all other region / product combinations, please google as usual.



Orders will be sent by FedEx ground, and orders can only be shipped to a US address. No P.O. boxes or APO addresses.

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 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 I consider all these cheap copies to be product piracy hurting those who invest in innovation.

Order your PLX Kiwi Wifi 2 from Amazon Deutschland. As long as the GoPoint BT1(A) and the OBDLink MX wifi are not available, the Kiwi is the best option available in Germany.

Order your Dual XGPS160 featuring 10 Hz  update rate and full support by Harry's LapTimer from Amazon Deutschland.

Order your RAM Mount RAM-B-166U from Amazon. Add either an iPhone4/4S cradle (RAM-HOL-AP9), or an iPhone5/5S cradle (RAM-HOL-AP11). For motorbikes, check the RAM-B-176 (plus cradle again).


Order your GoPoint BT1 or your PLX Kiwi Wifi 2 from Amazon. The GoPoint BT1(A) is the only Apple certified BT OBD available. It receives special support by Harry's LapTimer.

Order your Dual XGPS160 featuring 10 Hz update rate and full support by Harry's LapTimer from Amazon.

Visit OBD II dongle benchmark list on our forum

Order either a GoPro HERO3+ Silver Edition or the GoPro HERO3+ Black Edition Outdoor from Amazon Deutschland. To remote control these cams fully synchronized with lap timing, Harry's LapTimer GrandPrix Edition is required.

Order either a GoPro HERO3+ Silver Edition or the GoPro HERO3+ Black Edition from Amazon. To remote control these cams fully synchronized with lap timing, Harry's LapTimer GrandPrix Edition is required.

This page discusses compatible devices for iOS devices. Although the page is focussed a lot on Harry's LapTimer, it applies to all other Harry's apps mostly too.


The page starts with our up to date recommendation named "Harry's Choice". It is followed by a collection of links to distributors we like. The details start in the next sections, they are grouped by device type:

Optional for all apps - additional data available from your car's bus


Relevant for all apps - improved accuracy and data richness


Relevant for Harry's Heavy Duty - Camper Edition


In case you want to see more details on connection technologies used for smartphones, please check an article I have made available on the forum:

[FAQ] Bluetooth, Wi-Fi, or Plug-in Accessories?

Environmental Configurations

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 Heavy Duty - Camper Edition 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.

  1. Inexpensive

  2. Lots of sensors built in

  3. Incredible battery life time

  4. Allows distributed installation

  5. Easy to use

  1. Update rates and accuracies are lower than those of the sensors built into your iPhone

TI SensorTag

Recommended Configuration

Take care to install the latest firmware version for the SensorTag. Firmware updates are applied by installing the free SensorTag app from AppStore. At the time of writing, the latest version is 1.5 (and the SensorTag is coming with 1.4 pre-installed).


Optional for all apps but Buddy - better video quality than internal cam


Both GoPro and Sony cams are supported starting with v19 of all apps. GoPro's HERO4 Silver edition is probably the best choice.

Video Configurations (Action Cams)

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 versions treat all of this as 'hints' and will override LapTimer settings if they believe it is appropriate...

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

  1. Incredible video quality

  2. Wide angle lenses

  3. Wide range of models to fit individual requirements

  4. Memory inexpensive to add

  1. Lousy battery life time

  2. Premium pricing

GoPro HERO3/3+/4

Recommended Configuration

  1. Great video quality

  2. Wide angle lenses

  3. Wide range of models to fit individual requirements

  4. Memory inexpensive to add

  1. Lousy battery life time

Sony Cams

Recommended Configuration

Remarks: all HEROs starting with 3 come with the same support by LapTimer (et al). HERO3 cams show a huge lag in life previews. The better stream protocol used by HERO4 cams is not yet supported - instead a placeholder image is displayed. HERO2 cams with a BacPac(TM) added are reported to work with our apps too.

Remarks: compatible Sony cams come in a big variety and form factors. Features supported by LapTimer (et al) vary by model. While automatic swicthing of video resolution is probably not a critical item, only the HDR-AZ1, HDR-AS200, FDR-X1000, ILCE-QX1, and DSC-QX30 support an automatic transfer of footage from cam to iPhone.

The full and up to date list of all devices supported is available on Sony's website.

  1. Custom integration including multi CAN requests (GrandPrix)

  2. Rich set of functionality beyond OBD–has its own app ecosystem

  3. Seamless connection using Bluetooth (Mfi certified)

  1. Works with customized apps only

Automatic 2nd generation adapter

Recommended Configuration