Based on the provided `fly.toml` configuration file, here's a deployment guide for your `esp32-temp-chart` application on Fly.io. This guide assumes that you have already developed a Flask application that is ready to be deployed.

### Prerequisites

1. **Fly.io Account**: Ensure you have a Fly.io account. If not, sign up at [Fly.io](https://fly.io/).
2. **Fly CLI**: Install the Fly CLI tool. Instructions can be found on the [Fly.io documentation](https://fly.io/docs/hands-on/installing/).
3. **Docker**: Your application must be containerized with Docker. Install Docker if it's not already installed.
4. **Local Application Code**: Have your Flask application code ready on your local machine.

### Step-by-Step Deployment Guide

#### 1. Initialize Your Fly.io Application

- Navigate to your project directory in the terminal.
- Run `flyctl apps create esp32-temp-chart`. This command creates a new application on Fly.io with the name specified in your `fly.toml` file.

#### 2. Configure the `fly.toml` File

- Place your `fly.toml` file in the root of your project directory.
- Review the `fly.toml` file to ensure all configurations are correct. Particularly, check the `app` name, `primary_region`, and the `http_service` configurations.

#### 3. Set Up Docker

- Create a `Dockerfile` in your project root. This file should contain instructions to build a Docker image for your Flask application.
- Ensure that your application listens on the port specified in `fly.toml` (8080 in this case).

#### 4. Test Your Docker Container Locally (Optional)

- Build your Docker image: `docker build -t esp32-temp-chart .`
- Run your container locally to ensure it works: `docker run --rm -p 8080:8080 esp32-temp-chart`
- Test the local deployment by navigating to `http://localhost:8080`.

#### 5. Deploy Your Application

- From your project directory, run `flyctl deploy`. This command will build your application's Docker image and deploy it to Fly.io.
- Monitor the deployment process in your terminal to ensure it completes successfully.

#### 6. Verify the Deployment

- Once deployed, you can access your application using the URL provided by Fly.io.
- Test the `/ping` endpoint to ensure your application responds correctly.

#### 7. Monitoring and Management

- Use `flyctl logs` to view real-time logs from your application.
- Use `flyctl status` to check the status of your application.
- To scale your application, use `flyctl scale count <number_of_instances>`.

### Additional Notes

- The `[[mounts]]` section in `fly.toml` is used to persist data. Ensure the `source` and `destination` are correctly set for your application's data needs.
- The `[checks]` section defines health checks for your application. Adjust the `path`, `interval`, and `headers` as needed for your application's health endpoint.

Remember, always test your application locally before deploying to ensure it's working as expected. If you encounter issues, the Fly.io documentation and community forums are great resources for troubleshooting.