ddLooper user guide

This guide describes the current version of ddLooper. It covers every screen, button and setting.

What the app does
What you need
Your account, sign-in and devices
Opening the app
The start screen
Placing the camera
The live screen
First start with the microphone
The settings panel, section by section
Trigger mode: microphone (MIC)
Trigger mode: second phone (PHONE and MOTION SENDER)
Trigger mode: Bluetooth sensor (BT) (coming soon)
Watching the replay
Saving clips
AUTO MODE in practice
EXIT and the background rule
Without internet
Troubleshooting

General questions (devices, internet, privacy, trial and subscription) are answered in the Frequently asked questions on the ddLooper page.

1. What the app does

The camera runs all the time. The app keeps the last few seconds of video in the device’s memory. When a shot signal arrives, the app waits until the part after the shot is recorded. Then it builds a short clip and plays it in a loop.

Nothing is written to your device unless you press SAVE. The clips have no sound.

2. What you need

A phone, tablet or computer with a camera.
Chrome or Edge (version 94 or newer), or Safari on iOS/iPadOS 16.4 or newer. Other and older browsers are not supported.
Internet when you open the app and sign in. The phone trigger needs internet on both devices all the time.
For the Bluetooth sensor (coming soon): Chrome or Edge on Android or on a computer. iPhone and iPad cannot use Bluetooth in the browser.
For the PHONE trigger, the second phone (the sensor phone) needs a built-in motion sensor, a current operating system and a current browser (Chrome or Edge on Android, Safari on iPhone/iPad as in the list above). Most newer phones have all of this. If the phone or its system does not support keeping the screen awake and the screen goes to sleep while you train, switch off the automatic screen lock (screen timeout) in the phone settings yourself, or the program will not work correctly. On some older phone models the motion sensor or the browser is too old, and MOTION SENDER may not work there. A computer has no motion sensor.
For the MIC trigger: an external microphone (preferably wireless) or a piezo sensor on the bow handle is recommended for stable operation. See section 10.
A stand or tripod is a big help.

3. Your account, sign-in and devices

The app opens only for a signed-in ddmatrix.eu account with an active subscription.
The app checks your subscription when it opens, every few hours while it runs, each time you come back to it, and quickly again each time you press START LOOPER.
The app works only when it is opened from ddmatrix.eu (the Software page, your bookmark of /app/looper/ or the home screen icon). A copy of the page saved to a file or put on another address stays locked and shows “Please open the Looper from ddmatrix.eu.”
On every device you use, sign in with the same ddmatrix.eu account. This matters most for the phone trigger: two devices find each other through your account. No code is needed.
If you switch accounts in one browser, the app uses the account that is signed in right now.
You sign in on ddmatrix.eu with a passkey (Face ID, Touch ID or Windows Hello), with Google, or with a sign-in link by email (it works once, within 15 minutes). There is no password. A device stays signed in for up to 90 days.
To sign out, open Account in the top menu and press Sign out at the bottom of the page.
If you are signed out, the start screen shows “Please sign in to ddmatrix.eu again.” and a Sign in button. The START LOOPER and MOTION SENDER buttons stay grey until you sign in.
If no active subscription is found, the start screen shows a message and a See plans button. The saved copy of the app is then removed from that device.

IMAGE S3 (SCREENSHOT): start screen with the “Please sign in to ddmatrix.eu again.” message and the Sign in button

4. Opening the app

Sign in on ddmatrix.eu, go to the Software page and press Open next to ddLooper.
Or bookmark the address /app/looper/ and open it directly.
Add it to your home screen. It then opens like an app, without browser bars.
- Android (Chrome): menu ⋮ > Install app or Add to Home screen.
- iPhone/iPad (Safari): Share > Add to Home Screen.
- Computer (Chrome/Edge): the install icon in the address bar.

The app always loads the newest version when you are online. You do not need to update anything. The version number is shown at the bottom of the settings panel and on the MOTION SENDER screen.

5. The start screen

START LOOPER: starts the looper with the trigger you used last time (MIC, BT or PHONE). The first time, this is the microphone. To change the trigger, open the settings (⚙) after the start, see “Trigger input”.
Before the looper starts, a small window Athlete asks who is training (see below). The free trial does not ask, because it cannot save clips.
MOTION SENDER: turns this device into the motion sensor for another looper. The camera is not used.

6. Placing the camera

Use a stand or tripod. The picture must not move.
Side view or a view from behind works well. Make sure your whole bow and draw arm are in the picture.
In MIC mode, keep the microphone close enough to hear the shot clearly. For the best results use a piezo sensor on the bow handle or an external microphone. The built-in microphone of a computer or phone works only in a quiet place without noise from other people or machines. It is not suitable for public halls or a noisy environment. If the surroundings are noisy, use the PHONE or BT trigger instead (section 11; BT is coming soon, section 12).
Plug in the charger for long sessions. The screen stays on while the app runs.
Choose Landscape or Portrait in the settings before you start.

The athlete name at START

The name is used for the folder of saved clips (see “Saving” in section 9).

If a name is saved, the window asks “Continue with the name …?” Press Continue as … to keep it, or Another name to type a new one.
When you type a name, press Use this name (or Enter). Continue as noname starts without a name; the clips then go to the noname folder.
The first time, or when the saved name is “noname”, the window asks for a name straight away.
If you always train alone, tick Keep this name (do not ask at START) in the settings. Then START LOOPER starts at once with the saved name. With “noname” it still asks.

IMAGE S12 (SCREENSHOT): the Athlete window “Continue with the name …?” with the buttons Continue as … and Another name

IMAGE P2 (PHOTO): phone on a tripod at the shooting line, side view of the archer at full draw

7. The live screen

Gear ⚙ (top left): opens the settings.
Status (top): what the app is doing.
- WARMING UP: the app is filling its video memory. Wait a moment.
- ● LISTENING: ready for a shot.
- ● REC: a signal arrived; the part after the shot is being recorded.
- PROCESSING: the clip is being built.
- SWITCHING CAMERA: a new camera is starting.
- MIC OFF, NO CAMERA FRAMES: see Troubleshooting.
- BT NOT CONNECTED / BT CONNECTING / BT RECONNECTING and PHONE NOT CONNECTED / PHONE CONNECTING / PHONE RECONNECTING: the trigger is not connected yet.
Top bar (top centre): the trigger in use: MIC, BT or PHONE. Green means connected. BT ✕ or PHONE ✕ means not connected. In BT mode the sensor battery can show here (for example bat 45%). In PHONE mode the last motion peak from the sensor phone can show here (for example peak 63.0), and the estimated delay of the signal (for example delay ~25 ms). The delay is the time the signal needs to travel over the internet. It helps you choose the Sync offset.
Connect BT (top left, BT mode only): shown when the sensor is not connected.
EXIT (top right): stops everything.
“Sensor phone connected. Switch to the PHONE trigger?”: a message that can appear in MIC mode, see “Automatic switch from MIC to PHONE” in section 11.

IMAGE S4 (SCREENSHOT): live screen with the gear, ● LISTENING, MIC in the top bar and EXIT

8. First start with the microphone

Press START LOOPER. Answer the Athlete window (keep the name, type another one, or continue as noname).
Allow the camera and the microphone when the browser asks. On an iPhone home screen app, the question may come again each time.
Wait for ● LISTENING.
Calibrate before your first session (see section 10). This is important. Out of the box the microphone is set to the least sensitive level, so only very loud shots are detected.
Shoot. You see ● REC, then the clip plays in a loop.

9. The settings panel, section by section

Tap the gear ⚙ in live view. The settings open only in live view, not during playback. While the panel is open, shot signals are ignored. Tap Close when you are done. All settings are saved on the device and stay after a restart.

IMAGE S5 (SCREENSHOT): settings panel, top part with Camera and Trigger input

Camera

Camera list: choose which camera to use. Names may be general, like “Camera 1”.
Next camera: switches to the next camera. On phones this goes through front, back and any extra back cameras.
Filming speed: 30 fps (default) or 60 fps. 60 fps gives twice as many frames, which helps slow motion and frame stepping. The camera restarts with the new speed. If the camera cannot film at 60 fps, the button is grey or the app goes back to 30 fps and tells you. In poor light many cameras cannot keep 60 fps.
The line below shows the measured speed and what the camera reports.
When to change: use 60 fps in good light when you want smoother slow motion.

The app starts with the front camera until you choose another one. After a camera change the app shows WARMING UP for a moment.

Trigger input

MIC: the microphone hears the shot.
BT (coming soon, in development): a Bluetooth sensor sends the signal. Only on Android Chrome and desktop Chrome/Edge. Not on iPhone/iPad.
PHONE: a second phone running MOTION SENDER sends the signal.
In BT and PHONE mode the microphone is switched off completely. You can switch back to MIC at any time without restarting.
DEVICE_NAME: the name of the Bluetooth sensor to look for. Default Sensor_1. Leave it empty to go back to the default. The Bluetooth sensor is still in development.
Connect BT: opens the browser’s device list. When connected, it reads Reconnect / choose device.
The line below shows the BT state, for example “BT connected, bat 80%”.

Phone trigger

A note reminds you to sign in with the same ddmatrix.eu account on the sensor phone.
Sensor threshold (sensor phone): how hard the sensor phone must move to send a signal. Range 5 to 100 m/s², default 15. Left is more sensitive. You can change it here or on the sensor phone. Both stay the same; the last change wins. A change made here reaches the sensor phone while PHONE is connected. A sensor phone that connects later gets it too.
Restore default threshold (15): sets it back to 15.
Connect / Disconnect: connects or disconnects the phone trigger. If another trigger is in use, the button reads Use PHONE trigger and switches to PHONE.
The status line shows the connection, the time and strength of the last signal, and the last motion peak measured on the sensor phone.

Microphone sensitivity

Calibrate (3 shots): the app measures the background noise and three of your shots and sets the threshold. See section 10.
Threshold: the sound level a shot must reach, shown in dB. Range -60 dB (most sensitive) to -0.5 dB (least sensitive, the default).
Level bar: the blue bar is the sound right now. The red mark is the threshold.
Slider: left is more sensitive, right is less sensitive.
Calibrate and the threshold slider are grey in BT and PHONE mode.
For the best results with MIC, use a piezo sensor on the bow handle or an external microphone (see section 10).

Sync offset

Moves the clip earlier or later in time. Range -300 to +300 ms, steps of 10 ms, default 0.
A positive value moves the clip later. A negative value moves it earlier.
It works for MIC, BT and PHONE. It sits under Microphone sensitivity but is not greyed out in BT or PHONE mode.
When to change: if the release is not where you expect it in the clip. Bluetooth and the phone trigger arrive a little late, so they often need a negative value. As a starting point, try about -50 to -150 ms for BT and -150 to -300 ms for PHONE, then adjust.

Video ring buffer

Length: the clip length. 0.5 to 5 s, in steps of 0.5 s. Default 2 s.
Signal position: how much of the clip is before the shot and how much after. Shown as “1 s before | 1 s after”. Steps of 0.1 s. Default: the shot in the middle.
Playback starts only after the “after” part is recorded. A long “after” part means a longer wait.
When to change: more “before” to see your setup and draw; more “after” to see the follow-through.

IMAGE S6 (SCREENSHOT): settings with Video ring buffer (Length, Signal position) and AUTO MODE

AUTO MODE

Off by default.
When on, shots are also detected while a clip is playing. The next clip replaces the playing one. The old clip is dropped unless you saved it.
See section 15.

Screen orientation

Landscape (default) or Portrait.
Android Chrome locks the screen in that direction. On iPhone, iPad and computers the browser cannot lock it: the app tells you, and you rotate the device yourself (turn off rotation lock). The app works both ways.

Slow motion

SLOMO_SPEED: how many frames per second the SLOMO button shows. 1 to 30 fps, default 7.
The change works at once, also while slow motion is playing.
Saved videos always keep normal speed.

Saving

Athlete name: the name of the athlete who is training now. It is used as a folder name. Change it here, or in the Athlete window at START, when another athlete takes over. The name is saved on the device. The default name is noname.
Keep this name (do not ask at START): off by default. When it is not ticked, every START LOOPER asks whether to continue with the saved name or type another one (see “The athlete name at START” in section 5). When it is ticked, START LOOPER does not ask and uses the saved name. With the name “noname” it always asks.
Save folder (Chrome and Edge on a computer): at first the clips go to the Downloads folder. Press Browse… and choose a folder, for example a folder Documents\Archery\looper that you make once. The app remembers it. Use the Downloads folder goes back to normal downloads. A browser cannot be given a ready-made path, so you choose the folder once.
Clips are saved to save folder / athlete name / yyyy-mm-dd / yyyy-mm-dd_hh-mm-ss.mp4. The athlete folder and the day folder are made by the app. If you change the athlete name, the clips go to that athlete’s folder (made if it does not exist yet). With the name “noname”, the clips go to the noname folder.
The first time you press SAVE in a new session, the browser may ask once for permission to write to the folder. Allow it.
On phones, tablets and in other browsers a folder cannot be chosen. The clips then go to the Downloads folder (iPhone/iPad: the share sheet), and the athlete name is added to the file name.

Playback zoom

Zoom is always on. There is no switch for it.
Pinch with two fingers to zoom (up to 8x) and drag with two fingers to move. On a computer, the mouse wheel zooms at the cursor, and Shift + drag (or the right mouse button) moves the picture.
The zoom stays for the next clips until you press Reset zoom. Every time the looper starts, the zoom is back at 1:1 (no magnification).
SAVE writes the clip with this zoom.

Playback grid

Grid intensity: 0 (grid off) to 10 (solid), default 4. The grid is on by default.
Cell size: 30 to 200 px, default 50.
Colour: black, white (default), red, green or blue.
One grid line always goes through the centre of the screen.
While the settings are open, the grid also shows over the live picture, so you can line it up.
SAVE writes the clip with the grid.
When to use it: to check your body line, bow arm and head position from shot to shot.

IMAGE S7 (SCREENSHOT): settings with the Playback grid section and the grid preview over the camera picture

Debug

Debug: shows a technical log of the last events.
Copy log: copies it, so you can send it to support.
The version number is next to it.

10. Trigger mode: microphone (MIC)

In the settings, choose MIC (it is the default).
Tap Calibrate (3 shots). The settings close and a banner shows Calibrating… stay quiet.
Stay quiet for about 1.5 seconds.
The banner shows Shot 1/3. Shoot a normal shot. Then Shot 2/3 and Shot 3/3.
The banner shows Calibration complete and the new threshold. It is saved.
Press Cancel on the banner at any time to stop calibration.

IMAGE S8 (SCREENSHOT): calibration banner “Shot 1/3 make a normal shot” with the Cancel button

Which microphone to use

For stable operation of the app in MIC mode, an external microphone (preferably wireless) or a piezo sensor is recommended.
Best: a piezo sensor fixed to the bow handle, or an external microphone placed close to the bow. They pick up the shot clearly and hear little of the surroundings.
Built-in microphone of a computer, tablet or phone: usable only in a quiet place where no other noise disturbs. It is not suitable for public halls or a noisy environment: voices, other archers and machines can trigger it or hide the shot.
If the place is noisy and you have no piezo sensor or external microphone, use the PHONE trigger (section 11) or, when it is available, the BT sensor (coming soon, section 12).

Good to know:

The microphone reacts to a short, sharp, loud sound that is clearly louder than the background. It does not recognise the type of sound. Claps or a door bang can also trigger it.
After a signal, the app ignores new signals for 1.5 seconds. One shot gives one clip.
If shots are missed, calibrate again or move the threshold slider to the left. If other sounds trigger it, move it to the right.
Calibrate again when you change place, for example indoors to outdoors.

11. Trigger mode: second phone (PHONE and MOTION SENDER)

You need two devices:

the looper: the device with the camera,
the sensor phone: a phone fixed to your bow or held by you. It runs MOTION SENDER.

Note: the sensor phone must have a built-in motion sensor (accelerometer), and its operating system and Chrome/Edge (or Safari on iPhone) must be recent enough. Most newer phones qualify. If MOTION SENDER does not work on an older phone model, this is the usual reason; use a newer phone, or use the microphone trigger.

Both must be signed in with the same ddmatrix.eu account, and both need internet (Wi-Fi or mobile data; they can be on different networks).

IMAGE P3 (PHOTO): sensor phone fixed to the bow (for example on the stabilizer) next to the looper on a tripod

On the looper

Press START LOOPER. Then open the settings (⚙) and choose PHONE under Trigger input. Next time the app starts with PHONE by itself. If the sensor phone connects while the looper is in MIC mode, the app can also offer the switch (see below).
The app connects by itself. The top bar shows a green PHONE when it is ready. A short message “PHONE connected, your account” appears.
If the connection drops, the app tries again by itself (after 2.5, 5, 10 and then every 15 seconds).

Automatic switch from MIC to PHONE

You do not have to open the settings. When the looper runs in MIC mode and the sensor phone (MOTION SENDER, same account) connects, a message appears on the looper: “Sensor phone connected. Switch to the PHONE trigger?”

Switch to PHONE: the looper changes to the PHONE trigger and the microphone is switched off. You can go back to MIC at any time in the settings.
Stay on MIC: the message closes and the looper keeps using the microphone. It does not ask again while the sensor phone stays connected. If the sensor phone disconnects and connects again later, the message comes again.
The message appears only when the looper is in MIC mode, and both devices are signed in with the same ddmatrix.eu account.

On the sensor phone

Open the app and press MOTION SENDER.
Set the Threshold: 5 to 100 m/s², default 15. Left is more sensitive.
Press CONNECT & START SENSOR. On iPhone, allow motion sensor access.
The screen turns black and locks (see below). The phone goes full screen where the browser allows it, and the screen stays on.
When the phone moves harder than the threshold, it sends a signal. The dot flashes white and the looper shows the clip.

IMAGE S9 (SCREENSHOT): MOTION SENDER screen with Threshold slider, level bar, Last peak and CONNECT & START SENSOR

The lock screen

While the sensor runs, the whole screen ignores touches, so nothing is pressed by accident in your hand or pocket.

Dot: green means connected, red means not connected, a white flash means a signal was sent.
Text: SENSOR ON, NOT CONNECTED or NO SENSOR DATA.
Gear ⚙ (top right): hold it for about one second to open the settings. A short tap only shows the hint “Hold ⚙ to open settings”.
If full screen is lost (for example after a back gesture), tap the black screen to get it back.
iPhone Safari cannot show web pages full screen. Add the app to the Home Screen and start it from there; then the browser bars are gone.

IMAGE S10 (SCREENSHOT): sender lock screen, black with the green dot, “SENSOR ON” and the gear

Sender settings (when opened)

Threshold slider and a level bar: the bar shows the motion now; the red mark is the threshold.
Motion: the current motion in m/s².
Last peak: the strongest motion in the second after the last signal. The looper sees it too. Use it to choose the threshold: set the threshold clearly below your usual peak, but above normal handling.
Hide: back to the lock screen. The settings also lock again by themselves after 20 seconds without a touch.
Send test: sends one signal by hand. Good for checking the connection.
Stop: stops the sensor.
Back: stops the sensor and goes back to the start screen.

Good to know

After a signal, the sensor waits until the motion calms down (below 60% of the threshold) and at least 1 second has passed before it can send again. The looper also ignores repeats for 1.5 seconds.
The internet adds a small, changing delay. If the shot comes late in the clip, use a negative Sync offset on the looper.
The sensor phone must stay in the foreground with the screen on. The app asks the phone to keep the screen awake. If your phone model or system does not support this and the screen goes to sleep while you train, switch off the automatic screen lock (screen timeout) in the phone settings yourself, otherwise the program will not work correctly.
A computer has no motion sensor. It shows NO SENSOR DATA, but Send test still works.

12. Trigger mode: Bluetooth sensor (BT) (coming soon)

Coming soon: the Bluetooth sensor is still in development and is not yet available as a finished product. This section describes how it will work.

Works only in Chrome or Edge on Android or a computer.

Press START LOOPER.
In the settings, choose BT under Trigger input. The device list opens.
Check that DEVICE_NAME matches your sensor. If you change it, tap Connect BT again.
Choose your sensor in the list. The top bar shows a green BT. A message “BT connected” appears.
Close the settings and shoot.

Good to know:

Next time the app tries to connect to the same sensor by itself. If it cannot, tap Connect BT at the top left.
If the connection drops, the top bar shows BT ✕ and the app tries again every few seconds.
If the sensor sends its battery level, it shows in the top bar as bat %.
If the app says none of its services is on the device, the sensor is not compatible with the app.
Bluetooth arrives a little late. Adjust Sync offset if needed.

13. Watching the replay

The clip plays in a loop right after the shot.

IMAGE S11 (SCREENSHOT): playback screen with the three tap zones marked (left quarter, middle half, right quarter) and the frame counter

Tap the middle (middle half of the screen): pause or play. A pause sign shows.
Tap the left edge (left quarter): one frame back.
Tap the right edge (right quarter): one frame forward. The frame number shows at the top, for example “23 / 60”.
Drag one finger left or right: move through the clip frame by frame. The clip stays paused afterwards. On a computer, drag with the mouse.
Two fingers pinch to zoom, move to pan. On a computer, mouse wheel and Shift + drag.
Reset zoom (top left): removes the zoom. It shows only while zoomed.
SLOMO: plays the clip in slow motion at SLOMO_SPEED. The button turns blue and shows the speed, for example “SLOMO 7 fps”. Tap again for normal speed. Slow motion stays on for the next clips until you turn it off. Taps on the middle and edges also work in slow motion.
SAVE: saves the clip. See section 14.
NEXT: drops the clip and goes back to live view. Nothing is saved.
EXIT: stops everything.

Right after a drag or pinch, SAVE, SLOMO and NEXT ignore taps for a short moment, so a gesture does not press them by accident.

14. Saving clips

Press SAVE during playback.
The file is named like 2026-10-20_15-30-12.mp4 (date and time of the save). Two saves in the same second get a number at the end.
Where it goes:
- Computer (Chrome or Edge) with a save folder chosen in the settings: save folder / athlete name / date / file, see the Saving settings.
- Computer without a chosen folder, and Android: the Downloads folder (the athlete name is added to the file name).
- iPhone/iPad: the share sheet opens. Choose Save Video (to Photos) or Save to Files. If you close the share sheet, you see “Save cancelled”.
The button then reads SAVED.

With zoom or grid on, the saved video shows exactly what you see: the same zoom, position and grid. The app renders it first (the button reads RENDERING…, usually a few seconds). If that fails, the original clip is saved and a note tells you.

Saved videos are MP4 (H.264), without sound, at normal speed. Some gallery apps may show a tiny bit of extra video at the start.

15. AUTO MODE in practice

Turn on AUTO MODE in the settings if you want to shoot without touching the device.

During playback the top shows AUTO ● LISTENING.
When you shoot again, it shows ● REC. When the new clip is ready, it replaces the old one and plays.
The old clip is gone unless you saved it.
If you press NEXT while a new clip is recording, you go back to live view, and the new clip still plays when it is ready.

16. EXIT and the background rule

EXIT (top right, in live view and playback) turns off the camera, microphone, Bluetooth and the phone connection. A window “The looper is stopped” appears, and the start screen shows “Stopped. Camera and microphone are off. You can close this app.” Press OK and close the tab or app yourself; browsers do not let a page close itself.
Background rule: browsers stop the camera when the app is not on screen. If you switch to another app, lock the phone or let the screen turn off, the looper stops and the start screen shows “Paused because the app went to the background. Press START LOOPER to continue.” (no window appears). Your settings are kept.
Saving on iPhone (share sheet) does not count as leaving the app.

17. Without internet

After the app has loaded once and your subscription was confirmed, the looper keeps working without internet for up to 3 days (72 hours) with MIC and BT. The 3 days count from the last successful check. Setting the device clock back does not make them longer.
After that, connect to the internet once. The app says “Please connect to the internet once to confirm your subscription.”
PHONE and MOTION SENDER always need internet on both devices.
If the ddmatrix.eu server does not answer, the app tells you and keeps working for the same time.

18. Troubleshooting

A window “The looper cannot start” The looper could not start. The window tells you why. Read the text, press OK and fix the cause (see the next lines).

“No camera found on this device” The looper needs a camera for the instant replay. Connect a webcam, or open the page on a phone or tablet. Without a camera the app cannot run.

“No microphone found on this device” The MIC trigger needs a microphone. Connect a microphone, or choose the PHONE trigger (or BT, coming soon) instead. If a microphone is connected while the app is running, press EXIT and START LOOPER.

A window “The microphone cannot be used” The microphone failed to start (permission denied, no microphone or in use by another app). Fix it as the text says, or switch to PHONE (or BT, coming soon).

A window “The looper has stopped” Something went wrong while the looper was running, for example the camera was taken by another app or your subscription could not be confirmed. The window says what happened. Press OK, then START LOOPER.

The camera does not start / “permission denied” Allow camera (and microphone in MIC mode) for the site in the browser or system settings. Then press START LOOPER again.

“Camera … is busy or cannot be started” Another app uses the camera. Close it, then press START LOOPER.

“Camera was disconnected or taken by another app” Close other camera apps and press START LOOPER.

“This browser has no WebCodecs support” Use Chrome or Edge 94 or newer, or Safari on iOS 16.4 or newer.

“Camera access needs a secure (https) page” Open the app from the Software page or your bookmark, not from a saved file.

“Paused because the app went to the background” Normal. Press START LOOPER. Keep the app on screen and the screen on.

The status shows MIC OFF The microphone did not start. Check the microphone permission, then press EXIT and START LOOPER.

The status shows NO CAMERA FRAMES The camera stopped sending pictures. Press EXIT and START LOOPER, or choose another camera.

Shots are not detected (MIC) Calibrate again. Move the threshold slider to the left. Move the device closer. Check that the settings panel is closed and the top shows ● LISTENING. A built-in microphone often hears too little: use a piezo sensor on the bow handle or an external microphone, or the PHONE trigger.

Other noises trigger clips (MIC) Calibrate again, or move the threshold slider to the right. In a noisy hall the built-in microphone is not suitable: use a piezo sensor, an external microphone, the PHONE trigger (or the BT sensor, coming soon).

The shot is too early or too late in the clip Change Sync offset (with PHONE, the “delay ~ms” in the top bar shows the internet delay). Too late: go negative. Too early: go positive. You can also move Signal position.

The phone trigger does not arrive – Both devices signed in with the same ddmatrix.eu account? – Both online? Some school or company Wi-Fi networks block the connection; try mobile data. – Top bar on the looper shows green PHONE? Dot on the sensor phone green? – Press Send test on the sensor phone. If that works, lower the threshold. – Is the looper in live view (or playback with AUTO MODE) and the settings closed? – Sign out and in again on ddmatrix.eu on both devices, then reopen the app.

“Please open the Looper from ddmatrix.eu.” The app was opened from a saved file or from another address. Open it from the Software page on ddmatrix.eu, or from your bookmark of ddmatrix.eu/app/looper/.

The Athlete window comes at every START Normal. If you always train alone, type your name and tick Keep this name (do not ask at START) in the settings under Saving.

“Please sign in to ddmatrix.eu again” Tap Sign in, sign in, then open the app again.

“No active subscription” / See plans Check your subscription on ddmatrix.eu and that you are signed in with the right account.

The sensor stops working after a while The screen of the sensor phone probably went to sleep. Some phone models and systems cannot keep the screen awake for the app. Switch off the automatic screen lock (screen timeout) in the phone settings, keep the app on screen, and start the sensor again.

Sensor phone shows NO SENSOR DATA The browser gives no motion data. On iPhone, allow motion access and try again. A computer has no motion sensor.

“Motion sensor permission denied” On iPhone, allow “Motion & Orientation Access” for the site, then press CONNECT & START SENSOR again.

(Coming soon) BT is grey or “Web Bluetooth is not available” Use Chrome or Edge on Android or a computer.

BT sensor not in the device list Check DEVICE_NAME, switch the sensor on and keep it close. Bluetooth must be on.

60 fps is grey or goes back to 30 fps The camera cannot film at 60 fps, often because of low light. Use 30 fps or add light.

The screen does not rotate or lock On iPhone, iPad and computers rotate the device yourself and turn off rotation lock.

SAVE did not open the share sheet on iPhone After rendering with zoom or grid, iPhone may download the file instead. Look in Files > Downloads.

Something else is wrong Open settings > Debug, tap Copy log and send it to support together with a short description.

My settings are different on my other device Settings are saved per device. Only the sensor threshold is shared between the looper and the sensor phone.

For general questions, see the Frequently asked questions on the ddLooper page.

User guide

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