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1. Demo Mode

For Demo and Testing Purpose, the device can use pre-recorded images.

You need to enable it in the configuration (TakeImage > Demo) and also provide the needed files on the SD card.

For each round one image gets used, starting with the first image for the first round.

For the reference image and the alignment also the first image gets used.

Once the last image got reached, it starts again with the first one.

1.1 SD Card Structure

├── 520.8983.jpg
├── 520.9086.jpg
├── 520.9351.jpg
├── ...
└── files.txt
  • The jpg files can have any name
  • The jpg files must be smaller than 30'000 bytes
  • The files.txt must contains a list of those files, eg:

1.2 Recording

To record real images of a meter, you have to periodically fetch http://<IP>/img_tmp/raw.jpg.

To automate this, you can use the following shell script (Linux only):


while [[ true ]]; do
    echo "fetching value..."
    wget -q -O value.txt

    value=`cat value.txt`
    echo "Value: $value"

    diff=`diff value.txt value_previous.txt`
    #echo "Diff: $diff"

    if [[ $changed -ne 0 ]]; then
        echo "Value changed:"
        echo $diff
        echo "fetching image..."
        wget -q -O $value.jpg
        echo "Value did not change, skipping image fetching!"

    cp value.txt value_previous.txt

    echo "waiting 60s..."
    sleep 60

1.3 Installation

Just install the zip file using the OTA Update functionality.

1.4 How does it work

The Demo Mode tries to interfere as less as possible with the normal behavior. Whenever a Cam framebuffer gets taken (esp_camera_fb_get()), it replaces the framebuffer with the image from the SD card.

1.5 Example Data of a Water Meter

You can use the following demo images if you want:

530 00688

It covers a meter range from 530.00688 to 531.85882.

1.5.1 Animation

Animation of the watermeter (77 MB!)

1.5.2 Selection of 84 images



1.5.3 Selection of 42 images



1.5.4 All images (843 images)