Troubleshooting.

The camera or the microphone won't turn on

Under the tool a line tells you what happened. Look for the same sentence here.

Permission was denied

Your browser asked for permission and the answer was no, or you took it back earlier. Give it again like this, then reload the page and tap the button again.

1. On Android, in Chrome, tap the icon to the left of the address, then Permissions, and turn on Camera or Microphone.
2. On iPhone, in Safari, tap the button to the left of the address, then Website Settings, and choose Allow for Camera and Microphone.

Another app is using the camera

A video call or the Camera app left open can keep it busy. Close them and try again.

The browser doesn't give access to the camera

The camera, the microphone and the sensors only work on an https page. It also happens when you open the course from a link inside another app, like Instagram or Telegram, which use their own browser. Open the address in Chrome or Safari.

I can't find a camera

It happens on a computer without a webcam. The course is made for the phone, open it there.

On iPhone the motion sensors won't start

On iPhone the accelerometer and gyroscope ask for a separate permission, the first time you tap Turn on the sensors or the tool's button. Tap Allow.

You tapped Don't Allow

Safari remembers the answer and may not ask again. Close the tab, reopen the page and tap the button again. If the permission doesn't show up, delete this site's data in Settings, Safari (on recent iOS, Apps and then Safari), Advanced, Website Data. That also deletes the progress and lab projects saved in Safari, though.

Nothing comes in on a computer

A computer usually has no motion sensors, and the lab tells you after a couple of seconds. Open the page on your phone.

On Android only some readings come in

On Android no permission is needed. Some cheaper phones have no gyroscope, so only the acceleration comes in. The tools say so and work anyway.

The model won't download or is slow

The first time, each tool and each lab input downloads its model. Then it stays on the phone and works offline too.

• Photoabout 16 MB
• Handabout 20 MB
• Detector and segmentationabout 19 MB
• Textabout 135 MB, from Hugging Face
• Sound and Motionnothing to download

1. While it downloads, the line above the lab says what it's doing. Wait until it changes.
2. Use Wi-Fi for the sentence model. It's 135 MB, and on a slow connection it takes minutes.
3. If an error message shows up, reload the page with the connection on and try again.
4. Some school and office networks block Hugging Face. If the sentence model never starts, try another network.
5. In private browsing the browser may not keep the models, and downloads them every time. Use a normal tab.

The model answers slowly

The camera tools show in the top left how many milliseconds each frame takes, and whether they use the GPU or the CPU. On an older phone it takes longer, and that's normal. Close the other apps and don't keep the phone charging in the sun, because it slows down as it heats up.

The lab seems stuck

Almost always it's waiting for something, and the line at the top says so. Here are the most common waits.

1. Preparing the input, or Downloading the model. It's downloading the model, see point 3. The button stays gray until it's done.
2. A step won't open. The steps go in order. Train opens when you have some examples, Evaluate, Shrink and Use when there's a trained model.
3. Hold to record and nothing gets recorded. First turn on the camera, the microphone or the sensors. Then hold the button down, because a quick tap isn't enough.
4. Stop the continuous recording first. While it records continuously you can't switch class. Tap Stop continuous recording.
5. Saving the last examples, one moment. It's saving the examples it just took, then it opens the step you chose.
6. Epoch 12 of 60. It's training. Keep the screen on and the page open, because if you switch to another app the phone may slow it down or stop it.

If it really is stuck

Reload the page. The examples and the model are already saved on the phone, and the project opens again from Choose.

The course doesn't work offline

The course saves its pages the first time you open it with a connection, and each model the first time you use it. After that it works in airplane mode too.

1. Open the course once with a connection and wait a few seconds before you go offline.
2. Open once, with a connection, each tool and lab input you want to use offline.
3. The Listen voice isn't saved, because it's heavy. Offline, follow the lesson with Scroll & read.
4. In private browsing, or after clearing the browser data, nothing is kept. Open it again with a connection.
5. On iPhone the app on the Home Screen has its own memory, see point 6.

On iPhone, Safari and the Home Screen app

On iPhone you can add the course to the Home Screen with Share and then Add to Home Screen. The app you get has its own memory, separate from Safari.

1. Progress, cards and lab projects made in Safari don't show in the app, and the ones made in the app don't show in Safari.
2. The advice is to stay in Safari for the whole course. The saved pages work there in airplane mode too.
3. If you prefer the app, do everything from the app, lab included.
4. On Android the app installed from Chrome uses the same memory as Chrome, so you find everything.

Clearing the data saved in the browser

The course saves everything in the phone's browser and nothing on a server. Progress and answers sit in one place, lab projects, saved pages and models in another.

From the browser settings

You can also do it like this.

1. On Android, in Chrome, open Settings, then Site settings, All sites, choose this site and tap Clear and reset.
2. On iPhone open Settings, then Safari (on recent iOS, Apps and then Safari), Advanced, Website Data, search for this site and delete it.
3. On iPhone, removing the app from the Home Screen also deletes its data.