Alti-Force Sensor Pack Details

Upgrade your existing GoPro® video camera to record 3D action like the Hero5!

  • The Alti-Force Sensor Pack attaches directly to your GoPro camera for recording altitude/elevation and acceleration G-forces.
  • The Free Alti-Force GPS mobile app is also available to complement the sensor pack and add GPS speed, distance, and heading (bearing) to the recording.
  • The GPS Expander Board is a hardware GPS add-on with updates as fast as 25 times per second!

No post-processing required, record then play.

  • The chosen data are automatically saved in a subtitle track for display during video playback (raw data and GPS tracks can also be saved for analysis or map overlay).
  • Subtitle tracks can be enabled/disabled in a compatible player’s settings.
  • The video remains unmodified in its original quality; subtitles and data are saved in separate files.
    (Note: video editing may require additional steps to retain subtitles or add visual gauges)

Choose between two models: SP22 and the expandable SP30


  • Subtitled video playback for your GoPro camera¹
  • Altitude subtitles selectable as feet or meters
  • Acceleration G-force subtitles selectable as X-Y-Z axes or total magnitude
  • Compatible with GoPro Hero4 Black and Silver, Hero3+ Black and Silver, or Hero3 Black
  • Fits in GoPro cases with accessory backdoor² (available separately)
  • Speed, distance, and direction subtitles (Hero4 only)³

Great for athletes and hobbyists!

  • Skydiving, BASE Jumping, Speed Flying, Paragliding
  • Downhill Mountain Biking, Trail Riding, Motocross
  • General Aviation, Aerobatic Flights, Model Airplanes, UAVs
  • Auto Racing, Drag Racing, Rallying, Kart Racing
  • Snowboarding, Snow Skiing, Terrain Park
  • Hiking, Climbing, Rappelling
  • And many more!

¹ Requires a camera software update

² Altitude feature requires an open air vent. We recommend the Frame mount or our modified vented backdoor or a skeleton backdoor

³ Requires Hero4 camera receiving GPS data over Wi-Fi from Alti-Force GPS mobile app or using GPS Expander Board

Camera Compatibility

GoPro Hero3 Black – YES – firmware v03.00
GoPro Hero3+ Silver – YES – firmware v03.02
GoPro Hero3+ Black – YES – firmware v02.00 | v03.00* | v03.03*
GoPro Hero4 Silver – YES – firmware v05.00
GoPro Hero4 Black – YES – firmware v05.00

All efforts will be made to maintain compatibility with future firmware versions but cannot be guaranteed
*version disables USB mass storage mode, use of memory card reader is required

Case/Housing Compatibility

The GoPro camera with attached Alti-Force Sensor Pack fits in a standard camera housing with an ‘accessory backdoor’ (the deeper one, not the flat one).
The Altitude feature requires an open air vent. We recommend our modified vented backdoor or a skeleton backdoor for housings.  Frame mounts give the best audio and altitude response (although camera is unprotected).

Standard Housing
The original housing shipped with the GoPro Hero3 camera is larger than the newer version.  The Alti-Force Sensor Pack will fit in this housing with an original Hero3 accessory backdoor, but the housings are incompatible with newer accessory backdoors (including our available backdoors).
We recommend replacing the housing with a newer version made for Hero3+ and Hero4 cameras.  All three camera models are the same size and compatible with the newer housing and backdoors.

Frame Mounts
The original frame mount obstructed the back of the camera, preventing accessory attachment.  The newer frames available have open construction with a flip-out support to allow use with accessories.
Warning! Accessories are not well-secured with the frame and may be dislodged.
We recommend using a tie-wrap or rubber band to reduce the chance of losing your Alti-Force Sensor Pack or other accessory.

Player Compatibility

Any that support .SRT subtitle files (check your player’s specifications)

  • Includes most TVs and VLC media player (for all OS platforms)
  • Video must be played via USB mode or memory card reader
  • If copied off camera, video .MP4 and subtitle .SRT files must be copied together to same location

Note: QuickTime and Windows® Media Player do not natively support .SRT subtitles. (see this post for WMP)

Camera Modes

The Alti-Force Sensor Pack records data/subtitles in Video Mode only.

All standard video resolutions and frame rates are supported.

The Alti-Force Sensor Pack does not support Time Lapse and Looping video modes, and is disabled in all Photo modes.

Memory Card Compatibility

While we do not require any specific memory card, let it be known that the GoPro camera likes some and hates others. If you have any troubles after installing Alti-Force, it very well could be your memory card.

We can all learn from shared knowledge.  The Memory Card Table below is reproduced (with permission) from an article documenting a thorough testing of various memory cards and their GoPro compatibility.  In short, anything larger than 32 GB may give you trouble.

Be sure to read the article and look for the section called: Memory Cards: the Horror Story – Trial and Error.

Memory Card Table
Patriot 2Gb No No unknown
Samsung 4Gb No Yes MB-MS4GA/US
Toshiba 8Gb No Yes PFM008U-1DCK
Delkin SDHC 32Gb Yes Yes* DDMICROSDPRO2-32GB
Lexar SDHC 600x 32Gb Yes No LSDMI32GBSBNA600R
Lexar SDHC 633x 32Gb Yes No LSDMI32GBBNL633R
SanDisk Extreme 32Gb Yes Yes SDSDQXL-032G-AFFPA
Toshiba 32Gb No Yes* PFM032U-1DCK
Transcend 32Gb No No TS32GUSDU1E
Toshiba 64Gb No Yes* PFM064U-1DCK
Lexar microSDXC 64Gb No No LSDMI64GASBNAC10
Lexar SDXC 600x 64Gb Yes No LSDMI64GBSBNA600R
Lexar SDXC 633x 64Gb Yes No LSDMI64GBBNL633R
SanDisk Extreme Plus 64Gb Yes Yes SDSDQX-064G-U46A
SanDisk Ultra 64Gb No No SDSDQU-064G-AFFP-A


*The Delkin32 and Toshiba32 worked in the GoPro but refused to work with the card reader in the author’s Mac without using the supplied SD adapter. For this reason the card is rated untrustworthy.
*The Toshiba64 worked for 20 minutes then failed.


Model SP22

Size: 2.36 x 1.38 x 0.40 in (60 x 35 x 10 mm)

Weight: <1 oz (18 g)

Model SP30

Size: 2.32 x 1.61 x 0.40 in (59 x 41 x 10 mm)

Weight: <1 oz (14 g)


Standard camera voltage: 3.6v (powered from camera)

Minimal current draw: <2 mA typical


Tri-axial | ± 16 G’s | 0.1 G resolution


Absolute Pressure: 300 to 1100 mbar | 0.1 mbar resolution

Altitude range: -2000 to 30,000 feet | 1 ft resolution

Pressure to Altitude conversion assumes standard atmospheric conditions.

Sampling Rate

Hero 3/3+: approximately 4-6 samples per second

Hero 4:  approximately 25 samples per second

Subtitle Settings

Altitude: Feet | Meters | Both | None
Acceleration: XYZ axes | Total magnitude | All | None
G-bar: On | Off
Temperature: °F | °C | None

— GPS options (Hero4 only) —
Speed: MPH | Km/h | None
Distance: Miles | Kilometers | None
Heading: Degrees | None
GPS track GPX file: On | Off

— additional options —
Altitude offset: Feet only
Altitude smoothing: Low | Medium | High | None
Acceleration smoothing: Low | Medium | High | None
Data CSV file: On | Off

Before using this Alti-Force Sensor Pack with your camera, software needs to be installed on the camera.

The GoPro Hero3 Black and Hero3+ Black need only to run few files from your memory card; however, the GoPro Hero3+ Silver and Hero4 Black and Silver require a full update. Please note that when any update is performed, either from us or GoPro, you do so at your own risk, knowing that unexpected errors may occur that could render the camera inoperable.

Follow these easy steps to proceed with the install:

  1. Start with a fully charged battery.
  2. If your memory card is new, format the card in the camera.
  3. Remove the memory card from the camera and connect card to computer (via card reader).
  4. Download the installer program on the Downloads tab of the Support page and save it to the memory card.
  5. Run (double-click) the installer program (unzipped .jar file) on the memory card (main/root directory) and follow the on-screen instructions.

The camera will continue to function normally without the Alti-Force Sensor Pack attached, so an uninstall of our software is generally not necessary.

If you choose to uninstall the software, perform the standard update for the GoPro Hero3+ Silver and Hero4 Black and Silver.
For the GoPro Hero3 Black and Hero3+ Black, download the uninstaller program from the Downloads tab of the Support page.

The information on this Operation tab should be used as a quick reference only.
The complete operation guide can be found on the Literature tab of the Support Page.

Changing Subtitle Settings

  1. On a computer, run the Settings application – a file on the camera’s memory card named “settings.jar”.
  2. Choose the desired subtitle settings and click Save.

The last used settings should be shown when the Settings application opens.
The settings are stored on the memory card in a file named settings.txt (see an example here).

Recording Videos

  1. Attach the Alti-Force Sensor Pack, then power on the camera (One-button mode cannot be used, QuikCapture support requires v2.11+).
  2. Wait a few seconds for the top LED to flash red 3 times¹ = sensor pack is ready.
  3. Start video recording (Looping or Time Lapse modes not supported).
  4. Stop video recording, then wait a moment for the top LED to flash red 3 more times¹ = subtitles are saved and sensor pack is ready again.

Be sure to wait for 3 red flashes after stopping a video before starting the next recording, otherwise the sensor pack will not be ready and subtitles may not sync with the video start.

Setting Altitude Offset

  1. Attach the Alti-Force Sensor Pack and power on the camera.
  2. Wait a few seconds for the top LED to flash red 3 times¹ = sensor pack is ready.
  3. Press Mode button (on front of camera) until camera shows Setup screen (wrench or gears).
  4. Press and hold Select button (on top of camera) until top LED flashes red 3 times¹.  The altitude is now set to zero at the camera’s location.

The altitude offset can also be changed from a computer by running the Settings application (Settings.jar) on the camera’s memory card.

Field Calibrating Accelerometer Offsets

  1. Attach the Alti-Force Sensor Pack and power on the camera.
  2. Wait a few seconds for the top LED to flash red 3 times¹ = sensor pack is ready.
  3. Press Mode button (on front of camera) until camera shows Setup screen (wrench or gears).
  4. Place the camera on a flat and level surface.
  5. Press and hold Select button (on top of camera) until top LED flashes red 3 times¹.  Continue To Hold! (The altitude is now set to zero at the camera’s location.)
  6. Continue to hold the Select button until top LED begins flashing red, then release the button and camera. Camera must remain still for a few seconds.  The top LED will turn solid red, then again flash red 3 times¹.  The accelerometer offsets are now set.

Note this feature is available for serial numbers starting with 20F or 30F.

Watching Videos

  1. Attach the camera to a TV or computer via USB cable (not HDMI) to access the videos in USB mass storage mode; or use a memory card reader.
  2. Select the video and play!
  3. The selected subtitles are displayed on-screen by the video player².

If videos are renamed/copied/moved from the camera/card, be sure to also rename/copy/move the subtitle file, which has the same name as the video but ending with .SRT (e.g. GOPR1234.SRT).
Note: for editing, a “burn-in” software should first be used to permanently display the subtitle track on the video (subtitles added after editing or trimming would be out of sync).  DashWare is also available to import Alti-Force data as visual gauges and plots (as seen with Hero5 cameras).

Reviewing Data Files

  1. On a computer, browse to the location of recorded videos on the camera’s memory card (DCIM folder and subfolder).
  2. Locate the desired .mp4 video file. The data file(s) is(are) also in that location having the same name but with .csv extension (for comma-separated values data file) or .gpx extension (for GPS track file).
  3. Open the .csv data file in a spreadsheet format (see an example here), or analyze with alternate software methods.  The .gpx track file can be imported into a mapping software (such as Google Earth), or used in other software as desired.

¹ LED flashes for sensor pack status occur after, and in addition to, standard camera LED indication

² Subtitles are displayed on compatible video players only.  Click on the Compatibility tab for more information