This is the specification for the deployment-metadata.json file from Building deployment blocks.

export interface DeploymentMetadataV1 {
    version: 1;
    // Global deployment counter
    deployCounter: number;
    // The output classes (for classification)
    classes: string[];
    // The number of samples to be taken per inference (e.g. 100Hz data, 3 axis, 2 seconds => 200)
    samplesPerInference: number;
    // Number of axes ((e.g. 100Hz data, 3 axis, 2 seconds => 3)
    axesCount: number;
    // Frequency of the data
    frequency: number;
    // TFLite models (already converted and quantized)
    tfliteModels: {
        // Information about the model type, e.g. quantization parameters
        details: KerasModelIODetails;
        // Name of the input tensor
        inputTensor: string;
        // Name of the output tensor
        outputTensor: string;
        // Path of the model on disk
        modelPath: string;
        // Calculated arena size when running TFLite in interpreter mode
        arenaSize: number;
        // Number of values to be passed into the model
        inputFrameSize: number;
    }[];
    // Project information
    project: {
        name: string;
        // API key, only set for deploy blocks with privileged flag and development keys set
        apiKey: string | undefined;
    };
    // Impulse information
    impulse: DeploymentMetadataImpulse;
    // Sensor guess based on the input
    sensor: 'camera' | 'microphone' | 'accelerometer' | undefined;
    // Folder locations
    folders: {
        // Input files are here, the input folder contains 'edge-impulse-sdk', 'model-parameters', 'tflite-model'
        input: string;
        // Write your output file here
        output: string;
    };
}

export type ResizeEnum = 'squash' | 'fit-short' | 'fit-long' | 'crop';
export type CropAnchorEnum = 'top-left' | 'top-center' | 'top-right' |
                             'middle-left' | 'middle-center' | 'middle-right' |
                             'bottom-left' | 'bottom-center' | 'bottom-right';

export interface CreateImpulseStateInput {
    id: number;
    type: 'time-series' | 'image';
    name: string;
    title: string;
    windowSizeMs?: number;
    windowIncreaseMs?: number;
    imageWidth?: number;
    imageHeight?: number;
    resizeMode?: ResizeEnum;
    cropAnchor?: CropAnchorEnum;
}

export interface CreateImpulseStateDsp {
    id: number;
    type: string | 'custom';
    name: string;
    axes: string[];
    title: string;
    customUrl?: string;
}

export interface CreateImpulseStateLearning {
    id: number;
    type: string;
    name: string;
    dsp: number[];
    title: string;
}

export interface CreateImpulseState {
    inputBlocks: CreateImpulseStateInput[];
    dspBlocks: CreateImpulseStateDsp[];
    learnBlocks: CreateImpulseStateLearning[];
}

export interface DSPConfig {
    options: { [k: string ]: string | number | boolean };
}

export type DSPFeatureMetadataOutput = {
    type: 'image',
    shape: { width: number, height: number, channels: number }
} | {
    type: 'spectrogram',
    shape: { width: number, height: number }
} | {
    type: 'flat',
    shape: { width: number }
};

export interface DSPFeatureMetadata {
    created: Date;
    dspConfig: DSPConfig;
    labels: string[];   // the training labels
    featureLabels: string[];
    valuesPerAxis: number;
    windowCount: number;
    windowSizeMs: number;
    windowIncreaseMs: number;
    frequency: number;
    includedSamples: { id: number, windowCount: number }[];
    outputConfig: DSPFeatureMetadataOutput;
}

/**
 * Information necessary to quantize or dequantize the contents of a tensor
 */
export type KerasModelTensorDetails = {
    dataType: 'float32'
} | {
    dataType: 'int8';
    // Scale and zero point are used only for quantized tensors
    quantizationScale?: number;
    quantizationZeroPoint?: number;
};

export type KerasModelTypeEnum = 'int8' | 'float32' | 'requiresRetrain';

/**
 * Information required to process a model's input and output data
 */
export interface KerasModelIODetails {
    modelType: KerasModelTypeEnum;
    inputs: KerasModelTensorDetails[];
    outputs: KerasModelTensorDetails[];
}

export interface DeploymentMetadataImpulse {
    inputBlocks: CreateImpulseStateInput[];
    dspBlocks: (CreateImpulseStateDsp & { metadata: DSPFeatureMetadata | undefined })[];
    learnBlocks: CreateImpulseStateLearning[];
}

One of the most powerful features in Edge Impulse are the built-in deployment targets (under Deployment in the Studio), which let you create ready-to-go binaries for development boards, or custom libraries for a wide variety of targets that incorporate your trained impulse. You can also create custom deployment blocks for your organization. This lets developers quickly iterate on products without getting your embedded engineers involved, lets your customers build personalized firmware using their own data, or lets you create custom libraries.

In this tutorial you'll learn how to use custom deployment blocks to create a new deployment target, and how to make this target available in the Studio for all users in the organization.

Prerequisites

You'll need:

• The .

  • If you receive any warnings that's fine. Run edge-impulse-blocks afterwards to verify that the CLI was installed correctly.

Deployment blocks use Docker containers, a virtualization technique which lets developers package up an application with all dependencies in a single package. If you want to test your blocks locally you'll also need (this is not a requirement):

• installed on your machine.

Then, create a new folder on your computer named custom-deploy-block.

1. Getting basic deployment info

When a user deploys with a custom deployment block two things happen:

1. A package is created that contains information about the deployment (like the sensors used, frequency of the data, etc.), any trained neural network in .tflite and SavedModel formats, the Edge Impulse SDK, and all DSP and ML blocks as C++ code.

2. This package is then consumed by the custom deployment block, which can incorporate it with a base firmware, or repackage it into a new library.

If you now go to the Deployment page, a new option appears under 'Create library':

Once you click Build you'll receive a ZIP file containing five items:

• trained.tflite - if you have a neural network in the project this contains neural network in .tflite format. This network is already fully quantized if you choose the int8 optimization, otherwise this is the float32 model.

• trained.savedmodel.zip - if you have a neural network in the project this contains the full TensorFlow SavedModel. Note that we might update the TensorFlow version used to train these networks at any time, so rely on the compiled model or the TFLite file where possible.

• model-parameters - impulse and block configuration in C++ format. Can be used by the SDK to quickly run your impulse.

• tflite-model - neural network as source code in a way that can be used by the SDK to quickly run your impulse.

Store the unzipped file under custom-deploy-block/input.

2. Building a new binary

With the basic information in place we can create a new deployment block. Here we'll build a standalone application that runs our impulse on Linux, very useful when running your impulse on a gateway or desktop computer. First, open a command prompt or terminal window, navigate to the custom-deploy-block folder (that you created under 1.), and run:

This will prompt you to log in, and enter the details for your block.

2. Unzip under custom-deploy-block/app.

To build this application we need to combine the application with the edge-impulse-sdk, model-parameters and tflite-model folder, and invoke the (already included) Makefile.

2.1 Creating a build script

To build the application we use Docker, a virtualization technique which lets developers package up an application with all dependencies in a single package. In this container we'll place the build tools required for this application, and scripts to combine the trained impulse with the base application.

First, let's create a small build script. As a parameter you'll receive --metadata which points to the deployment information. In here you'll also get information on the input and output folders where you need to read from and write to.

Create a new file called custom-deploy-block/build.py and add:

build.py

Next, we need to create a Dockerfile, which contains all dependencies for the build. These include GNU Make, a compiler, and both the build script and the base application.

Create a new file called custom-deploy-block/Dockerfile and add:

Dockerfile

2.2 Testing the build script with Docker

To test the build script we first build the container, then invoke it with the files from the input directory. Open a command prompt or terminal, navigate to the custom-deploy-block folder and:

1. Build the container:
2. Invoke the build script - this mounts the current directory in the container under /home, and then passes the downloaded metadata script to the container:

Or if you run Windows or macOS, you can use Docker to run this application:

3. Uploading the deployment block to Edge Impulse

With the deployment block ready you can make it available in Edge Impulse. Open a command prompt or terminal window, navigate to the folder you created earlier, and run:

This packages up your folder, sends it to Edge Impulse where it'll be built, and finally is added to your organization. The transformation block is now available in Edge Impulse under Deployment blocks. You can go here to set the logo, update the description, and set extra command line parameters.

Privileged mode

4. Using the deployment block

The deployment block is automatically available for all organizational projects. Go to the Deployment page on a project, and you'll find a new section 'Custom targets'. Select your new deployment target and click Build.

And now you'll have a freshly built binary from your own deployment block!

5. Conclusion

Custom deployment blocks are a powerful tool for your organization. They let you build binaries for unreleased products, let you package up impulse as custom libraries, or can let your customers deploy to private targets (if you add an external collaborator to a project they'll have access to the blocks as well). Because the deployment blocks are integrated with your project, and hosted by Edge Impulse this lets everyone, from FAE to R&D developer, now iterate on on-device models without getting your embedded engineers involved.