> For the complete documentation index, see [llms.txt](https://docs.blynk.io/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.blynk.io/en/legacy-platform.md).

# Legacy Platform Help Articles

- [Legacy articles](https://docs.blynk.io/en/legacy-platform/legacy-articles.md)
- [What is Virtual Pins](https://docs.blynk.io/en/legacy-platform/legacy-articles/what-is-virtual-pins.md): Exchange any data between Blynk app and your hardware
- [Keep your void loop() clean](https://docs.blynk.io/en/legacy-platform/legacy-articles/keep-your-void-loop-clean.md): Troubleshooting of one of the most popular mistakes of newbie Blynk users.
- [How to control anything with Blynk app](https://docs.blynk.io/en/legacy-platform/legacy-articles/how-to-control-anything-with-blynk-app.md): Turn your things On / Off or send any data from Blynk app to hardware
- [NodeMCU](https://docs.blynk.io/en/legacy-platform/legacy-articles/nodemcu.md)
- [ESP8266 standalone](https://docs.blynk.io/en/legacy-platform/legacy-articles/esp8266-standalone.md)
- [Particle Electron](https://docs.blynk.io/en/legacy-platform/legacy-articles/particle-electron.md)
- [ESP8266 with AT firmware](https://docs.blynk.io/en/legacy-platform/legacy-articles/esp8266-with-at-firmware.md)
- [Bluetooth (2.0 SPP, 4.0 LE)](https://docs.blynk.io/en/legacy-platform/legacy-articles/bluetooth-2.0-spp-4.0-le.md)
- [USB Serial](https://docs.blynk.io/en/legacy-platform/legacy-articles/usb-serial.md)
- [Raspberry Pi and Blynk](https://docs.blynk.io/en/legacy-platform/legacy-articles/raspberry-pi-and-blynk.md): How to connect Raspberry Pi and Blynk
- [BBC micro:bit + Arduino IDE](https://docs.blynk.io/en/legacy-platform/legacy-articles/bbc-micro-bit-+-arduino-ide.md)
- [Blynk and Raspberry Pi: Tips & Tricks](https://docs.blynk.io/en/legacy-platform/legacy-articles/blynk-and-raspberry-pi-tips-and-tricks.md)
- [How to install Node.js library on Linux](https://docs.blynk.io/en/legacy-platform/legacy-articles/how-to-install-node.js-library-on-linux.md)
- [Node.js vs. C++ library](https://docs.blynk.io/en/legacy-platform/legacy-articles/node.js-vs.-c++-library.md)
- [Implementing a Blynk client (library)](https://docs.blynk.io/en/legacy-platform/legacy-articles/implementing-a-blynk-client-library.md)
- [App and board logs. How to send application and board logs correctly](https://docs.blynk.io/en/legacy-platform/legacy-articles/app-and-board-logs.-how-to-send-application-and-board-logs-correctly.md): Logs are a very powerful tool in the hands of our developers. Using them we can find a cause of an issue within a minimum amount of time.
- [Blynk Android permissions explained](https://docs.blynk.io/en/legacy-platform/legacy-articles/blynk-android-permissions-explained.md)
- [How to find code for my hardware?](https://docs.blynk.io/en/legacy-platform/legacy-articles/getting-started.md): Does my hardware work with Blynk? Which example code should I use with my hardware?


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