Whitespace is the programmers punctuation mark
This solution is an evolution of my ANT+ Class Libraries project. Whimsically, it grew out of my desire to show my friends at the local watering hole what I was working on. I wanted to pull out my phone, launch my fancy MAUI app, connect to my computer at home, interact with the ANT sensors I was simulating on my home computer, and savor a sip of bourbon!
I was looking at various homelab setups and VPNs and came across Tailscale. Tailscale checked all my boxes - free with a decent feature set, simple setup/administration, and secure. I didn't want to open the gates to just any hacker or script kiddie.
I set up Tailscale on my home computer and my phone, and I was able to connect to my home network, aka tailnet. This was great, but I needed a way to interact with my ANT+ sensors over Tailscale.
gRPC is a modern, high-performance framework for remote procedure calls. It uses HTTP/2 for transport, and Protocol Buffers as the interface description language. gRPC is well-suited for connecting and communicating between distributed systems.
The AntGrpc.Shared project contains the Protocol Buffer definitions and generates code for both the server and client applications. It defines the services and messages used for communication between the gRPC server and the MAUI client application.
The AntPlusServer project is an ASP.NET console application that hosts the gRPC server. It listens for incoming connections from clients and handles requests to interact with ANT+ sensors. One of the primary NuGet packages used by the server is the Small Earth Technology ANT USB Stick package. It handles the low-level interaction with the ANT USB-m stick. Note that the server is configured for the Windows platform, x86, as the ANT USB-m stick is only supported on Windows.
It runs on my home computer, which is connected to the ANT+ sensors via two ANT USB-m sticks. One stick serves as a simulator for various ANT+ sensors, while the other stick is used by the gRPC server to interact with the simulated sensors. I use SimulANT+ to simulate the ANT+ sensors.
The AntPlusMauiClient project is a cross-platform mobile application built with .NET MAUI. It serves as the client that connects to the gRPC server hosted by the AntPlusServer project. The MAUI app provides a user-friendly interface to interact with ANT+ sensors remotely. One of the primary NuGet packages used in this application is the Small Earth Technology ANT+ Class Libraries hosting extension, which provides the necessary functionality to communicate with ANT+ devices.
The MAUI client application is configured to connect to the gRPC server using the Tailscale service name. This allows the app to communicate securely with the server over the Tailscale network, without needing to expose any ports or configure firewalls. The application can also be configured to connect to the server using its IP address and port, but using the Tailscale service name is more convenient and secure. The localhost configuration is also available for testing purposes when running the server and client on the same machine. See the #define directive at the top of AntRadioService.cs for more details.
I've added my phone and my PC to my tailnet per Tailscale documentation. I also created a docker container that serves as the host for the Tailscale service I've defined. The reason for this is that a tag based identity is required for Tailscale service hosts, and I didn't want to add a tag to my home computer. The container is configured to run the Tailscale service and connect to my tailnet using the Tailscale CLI. This allows the gRPC server to communicate with the MAUI client application over the Tailscale network. See Use Docker Compose.
I create the docker container from a simple docker-compose.yml file. I execute docker compose up -d from a terminal command line at
the same directory level that the compose file is located in.
- Small Earth Technology ANT+ Class Libraries: Small Earth Technology ANT+ Libraries docs.
- Software Tools - THIS IS ANT: Tools available from Garmin/Dynastream.
- Tailscale Documentation: Official Tailscale documentation and guides.
- Docker Documentation: Official Docker documentation and resources.
- gRPC Documentation: Official gRPC documentation and resources.
- .NET MAUI Documentation: Official .NET MAUI documentation and tutorials.
- .NET MAUI Community Toolkit: Community toolkit for .NET MAUI applications.
- .NET MVVM Toolkit: MVVM toolkit for building maintainable applications.