@ -148,7 +148,7 @@ After the connection, all data sent to the IoT Hub from the device, or to the de
### X.509 certificates
When you are using an asymmetric encryption with a public/private key pair, you need to provide your public key to anyone who wants to send you data. The problem is, how can the recipient of your key be sure it's actually your public key, not someone else pretending to be you? Instead of providing a key, you can instead provide your public key inside a certificate that has been verified by a trusted third party, called an X.509 certificate.
When you are using asymmetric encryption with a public/private key pair, you need to provide your public key to anyone who wants to send you data. The problem is, how can the recipient of your key be sure it's actually your public key, not someone else pretending to be you? Instead of providing a key, you can instead provide your public key inside a certificate that has been verified by a trusted third party, called an X.509 certificate.
X.509 certificates are digital documents that contain the public key part of the public/private key pair. They are usually issued by one of a number of trusted organizations called [Certification authorities](https://wikipedia.org/wiki/Certificate_authority) (CAs), and digitally signed by the CA to indicate the key is valid and comes from you. You trust the certificate and that the public key is from who the certificate says it is from, because you trust the CA, similar to how you would trust a passport or driving license because you trust the country issuing it. Certificates cost money, so you can also 'self-sign', that is create a certificate yourself that is signed by you, for testing purposes.
The last stage for feed before it reaches consumers is retail - the markets, greengrocers, supermarkets and stores that sell produce to consumers. These stores want to ensure they have produce out on shelves for consumers to see and buy.
One of the most manual, time consuming tasks in food stores, especially in large supermarkets, is making sure the shelves are stocked. Checking individual shelves to ensure any gaps are filled with produce from store rooms.
IoT can help with this, using AI models running on IoT devices to count stock, using machine learning models that don't just classify images, but can detect individual objects and count them.
In these 2 lessons you'll learn how to train image-based AI models to count stock, and run these models on IoT devices.
> 💁 These lessons will use some cloud resources. If you don't complete all the lessons in this project, make sure you [Clean up your project](../clean-up.md).
## Topics
1. [Train a stock detector](./lessons/1-train-stock-detector/README.md)
1. [Check stock from an IoT device](./lessons/2-check-stock-device/README.md)
## Credits
All the lessons were written with ♥️ by [Jim Bennett](https://GitHub.com/JimBobBennett)
Smart assistants are not one-way communication devices. You speak to them, and they respond:
"Alexa, set a 3 minute timer"
"Ok, your timer is set for 3 minutes"
In the last 2 lessons you learned how to take speech and create text, then extract a set timer request from that text. In this lesson you will learn how to set the timer on the IoT device, responding to the user with spoken words confirming their timer, and alerting them when their timer is finished.
In this lesson we'll cover:
* [Thing 1](#thing-1)
* [Text to speech](#text-to-speech)
* [Set the timer](#set-the-timer)
* [Convert text to speech](#convert-text-to-speech)
## Text to speech
## Set the timer
The timer can be set by sending a command from the serverless code, instructing the IoT device to set the timer. This command will contain the time in seconds till the timer needs to go off.
### Task - set the timer using a command
1. In your serverless code, add code to send a direct method request to your IoT device
> ⚠️ You can refer to [the instructions for sending direct method requests in lesson 5 of the farm project if needed](../../../2-farm/lessons/5-migrate-application-to-the-cloud/README.md#send-direct-method-requests-from-serverless-code).
You will need to set up the connection string for the IoT Hub with the service policy (*NOT* the device) in your `local.settings.json` file and add the `azure-iot-hub` pip package to your `requirements.txt` file. The device ID can be extracted from the event.
1. The direct method you send needs to be called `set-timer`, and will need to send the length of the timer as a JSON property called `time`. Use the following code to build the `CloudToDeviceMethod` using the `total_time` calculated from the data extracted by LUIS:
> 💁 You can find this code in the [code-command/functions](code-command/functions) folder.
### Task - respond to the command on the IoT device
1. On your IoT device, respond to the command.
> ⚠️ You can refer to [the instructions for handling direct method requests from IoT devices in lesson 4 of the farm project if needed](../../../2-farm/lessons/4-migrate-your-plant-to-the-cloud#task---connect-your-iot-device-to-the-cloud).
1. Work through the relevant guide to set a timer for the required time:
> 💁 You can find this code in the [code-command/wio-terminal](code-command/wio-terminal), [code-command/virtual-device](code-command/virtual-device), or [code-command/pi](code-command/pi) folder.
## Convert text to speech
The same speech service you used to convert speech to text can be used to convert text back into speech, and this can be played through a microphone on your IoT device.
### Task - convert text to speech
Work through the relevant guide to convert text to speech using your IoT device:
@ -83,8 +83,8 @@ We have two choices of IoT hardware to use for the projects depending on persona
| 16 | [Manufacturing](./4-manufacturing) | Check fruit quality from an IoT device | Learn about using your fruit quality detector from an IoT device | [Check fruit quality from an IoT device](./4-manufacturing/lessons/2-check-fruit-from-device/README.md) |
| 17 | [Manufacturing](./4-manufacturing) | Run your fruit detector on the edge | Learn about running your fruit detector on an IoT device on the edge | [Run your fruit detector on the edge](./4-manufacturing/lessons/3-run-fruit-detector-edge/README.md) |
| 18 | [Manufacturing](./4-manufacturing) | Trigger fruit quality detection from a sensor | Learn about triggering fruit quality detection from a sensor | [Trigger fruit quality detection from a sensor](./4-manufacturing/lessons/4-trigger-fruit-detector/README.md) |
| 19 | [Retail](./5-retail) | | |
| 20 | [Retail](./5-retail) | | |
| 19 | [Retail](./5-retail) | Train a stock detector | Learn how to use object detection to train a stock detector to count stock in a shop | [Train a stock detector](./5-retail/lessons/1-train-stock-detector/README.md) |
| 20 | [Retail](./5-retail) | Check stock from an IoT device | Learn how to check stock from an IoT device using an object detection model | [Check stock from an IoT device](./5-retail/lessons/2-check-stock-device/README.md) |
| 21 | [Consumer](./6-consumer) | Recognize speech with an IoT device | Learn how to recognize speech from an IoT device to build a smart timer | [Recognize speech with an IoT device](./6-consumer/lessons/1-speech-recognition/README.md) |
| 22 | [Consumer](./6-consumer) | Understand language | Learn how to understand sentences spoken to an IoT device | [Understand language](./6-consumer/lessons/2-language-understanding/README.md) |
| 23 | [Consumer](./6-consumer) | Set a timer and provide spoken feedback | Learn how to set a timer on an IoT device and give spoken feedback on when the timer is set and when it finishes | [Set a timer and provide spoken feedback](./6-consumer/lessons/3-spoken-feedback/README.md) |
Jim Bennett
3 years ago
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