How to Set Up an Arduino Nano (Including the CH340 Driver)
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The Arduino Nano is a compact board that fits neatly on a breadboard, which makes it a favourite for small builds and wearables. Most Nano boards sold today are clones that use the CH340 USB chip, so the one extra step beginners trip on is the CH340 driver. This guide walks through the whole setup. If you are still deciding what to build, Compoden's AI build assistant can take a description of your project and return the parts, wiring, and code as a ready-to-ship kit.
1. What you need
You need an Arduino Nano, a USB cable, and a computer. Older Nano boards use a Mini-USB cable, while newer ones use Micro-USB or USB-C, so check the socket on your board before grabbing a cable. The Nano has a built-in LED on pin 13, so you do not need any extra components for the first test.
2. Install the Arduino IDE
Download the Arduino IDE from arduino.cc and install it for your operating system. This is the program where you write your sketch and upload it. On Windows, allow any driver prompts during installation. The IDE works the same on the Nano as it does on every other Arduino board.
3. Install the CH340 driver
This is the key step for the Nano. Most Nano clones use a CH340 USB-to-serial chip, and your computer needs its driver to see the board. Search for the CH340 driver, download the version for your operating system, and run it. On Windows, install it, then unplug and replug the Nano so a new COM port appears. On macOS you may need to allow the driver in System Settings under Privacy and Security after installing. Once the driver is in place, the board shows up as a serial port.
4. Select your board and port
In the Arduino IDE, open Tools, then Board, and choose Arduino Nano. Then open Tools, then Port, and select the CH340 port that appeared. On Windows it looks like COM4, and on macOS it looks like /dev/cu.wchusbserial followed by numbers. One Nano-specific setting matters: open Tools, then Processor, and if uploads fail, switch to "ATmega328P (Old Bootloader)," which many clones use.
5. Upload your first sketch
Open File, then Examples, then 01.Basics, then Blink. Click the Upload arrow. The IDE compiles the sketch and sends it over the CH340 port. When you see "Done uploading," the LED near pin 13 should blink once per second. That single test confirms the driver, the port, and the board are all working together.
6. Troubleshooting
If no port appears, the CH340 driver is almost always the reason, so reinstall it and try a different USB port. If the port appears but uploads fail, switch the Processor option to the Old Bootloader as described above. A charge-only cable is another common culprit, so use a cable you know carries data. Pressing the reset button on the Nano just as the upload starts can also rescue a stubborn upload.
Build it with Compoden's AI
With Blink running, your Nano is ready for real work. Tell Compoden's AI build assistant what you want to make, such as a wearable step counter or a tiny weather station, and it recommends the components, shows the wiring to your Nano, and provides starter code. It then ships the matching kit so you are not left chasing individual parts. Explore boards and kits at /collections/all.
The Nano is only tricky because of the CH340 driver, and once that is installed the rest is routine. Install the IDE, add the driver, pick the board and port, and upload Blink. Then let the AI assistant plan and ship your next project from Compoden.
Why does my Nano not appear as a COM port? Almost always because the CH340 driver is missing. Install the CH340 driver, replug the board, and check that you are using a data USB cable rather than a charge-only one.
Uploads fail even though the port is selected. What now? Open Tools, then Processor, and choose ATmega328P (Old Bootloader). Many Nano clones ship with the old bootloader and will not upload otherwise.
Which USB cable does the Nano use? It depends on the board. Older Nanos use Mini-USB, while newer versions use Micro-USB or USB-C. Check the socket before buying a cable.