Wemos D1 Mini not recognised by Windows with no COM port

This blog post describes what you can do if Windows doesn’t recognise the Wemos D1 Mini and there is no COM port to use it.

Do this first: Check your Cable!

Your Wemos might not be found due to a faulty cable. Some cables will only transmit power and will not work.

Try using another cable, any one from an android phone should work with the Wemos. If this doesn’t work then try the next steps. Lots of readers of this post found that simply changing the cable worked!

Why is there no COM port for my Wemos D1 Mini

The standard USB-to-serial drivers installed on Windows does not currently support the USB-to-serial chip used in the Wemos D1 Mini.

The Wemos D1 Mini won’t show in the Arduino IDE until this issue is resolved. If you are using another program to program the D1 Mini you won’t have the emulated COM port needed to program it.

However it is relatively easy to fix this by installing the correct driver for the USB-to-serial chip.

Installing the required driver

The Wemos website has the correct driver to use for the USB-to-serial chips in their Wemos range. This includes the Wemos D1 mini which I am having trouble with.

You can download the driver from their downloads website.

I downloaded the zip file ch341ser_win.zip and ran the executable in that zip file. The zip file hashes are reproduced below:

9f9da70c4581951c6369cc60adee91de *ch341ser_win.zip
ed61aef8dc647bbe33a314170af256973dd6d62f *ch341ser_win.zip
7fb53c7a175f7716f43922ac5f4955f05d07db97a7d42b2a0e143b010488617401f9a815bfed43dfc6dd5ea24afcd8f50b5cfec8ec8b7ed9fc9768d80c3cb723 *ch341ser_win.zip

Once the driver was installed Windows reloaded the Wemos D1 mini and correctly found the driver. The COM port then appeared in the Arduino IDE and I could successfully load programs onto it.

If you have any questions about getting the Wemos D1 Mini to work feel free to ask below.

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